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1977 Honda CB400 Four Project - Rookie

36K views 103 replies 31 participants last post by  radambomb 
#1 ·
Hi guys. I'm not sure on what the etiquette is on this, but I've posted this over at the SOHC4 forums. However a friend told me this was THE place for cafe racer projects and advice, so I thought maybe I should post them in both forums so everyone can follow my progress.

I'm 25, live in Melbourne, Australia. Doug inspired me to have a crack at building a bike. I'll be honest, I don't know a whole lot about mechanicals. I've always been a bit of a computer nerd. Anyway, I figured I'd have a go at building a cafe racer inspired CB400 Four on a budget.





Here it is. Not much to look at. I'll be honest, I bought this bike unseen from South Australia for $1000 AUD. It was a gamble. However it all seems to be there in one way or another, even if it has some rust and holes in it. It doesn't drip anything.



I haven't been able to get it started. I'm not sure about it. There's a lot of superficial rust, a good size hole in the 4-into-1 collector, the muffler is toast, the seat busted, the battery was missing, the forks have some rust pitting, some of the spokes aren't great and the tank has some bog in it and is dinged up. The electric start is broken. The highlight doesn't work but the front indicators do. The rear aren't connected. The headlight bucket is cracked, as is one of the gauge buckets. The gears seem to select. The brakes function but won't stop the bike in a hurry. The chain and sprocket appear ok if a little rusted. The kick start is loose, as is the foot brake.







I cleaned the tank out with some petrol. This is what came out. I wonder how that bug liked petrol fumes?



I pinched a friends battery. Grabbed another friend to help (pictured), then put the tank back on, zip-tied the fuel hose on to the carburetor and fuel tap as it was very loose and started her up. As I said, the electric starter just makes a single click the the power shuts off. However the kick starter got it going fine when I gave it some throttle. It won't idle for long, even with the choke fully on. I might try cleaning the plugs and putting some WD-40 (lubricating oil in a can for those non-Australians) down the throttle cables to loosen them up a bit. With the holes in the header collector it's hard to hear anything specific about how the engine is running. There's plenty of smoke coming out. I'll try the oil.





I didn't bleed it completely, just enough to see if anything obvious fell out. It appeared pretty clear to me.



I don't know anything about engines really. I'm not sure about the compression as I don't have a tester, but the carburetors appear to function and aren't dirty if I take the caps off. I didn't get too stuck into it as I'm taking it to a Honda mechanic a buddy used for his resto CB250 project to get an informed decision before I continue.

Update:

Ok so I put the bike on a trailer and took it around to this Honda mechanic's house. It was a sobering experience. He told me, without really starting it or taking anything off it, that it appears to have a head gasket problem (there was a leak stain he showed me that indicated this apparently), the rims and rubbers will need replacing, so will all the cables, everything will need cleaning or replacing (bolts, cables, guards etc) and thought the rubber connecting the engine to the carburetor (what are they called?) would need replacing. Obviously all the filters need replacing. The entire exhaust system would need to be replaced as it's got hole in it. He even said that the cylinder's would most likely need re-boring (he mentioned that would cost about $250 a cylinder). He said the front forks would need to be rebuilt too. He said he could take a more in depth look at it during the week, but he'd be taking money from me as it's not worth it. He said sell it and look for something that costs a bit more money initially but will require less engine work.

Obviously this is shattering news to me. I had expected to do a whole bunch of cleaning, powder coating and the odd bit of chrome. I knew the headers and muffler would have to be replaced. But an engine rebuild? I was hoping to avoid this so early on in the project. I knew getting a 4 cylinder bike unseen for $1000 AUD would be risky, but I was hoping I'd get away with something I could get good with my own hard work and a lot of cleaning/paint/new parts. Maybe that was naive.

I'm at a crossroads. I really have fallen in love with the CB400 Four and can't imagine anything else, but I haven't seen many come up for sale on the internet in the last few months. Should I sell this and wait for something that might cost a little more up front but won't require so much work to get it running decently? Argh! Decisions!

I'm devastated.

Rick.
 
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#2 ·
Ok so that mechanic just looked over it. I was standing with him when he was going over it. He didn't start it or really even touch the bike. He said he works in a Honda shop, has owned Honda's for 20 years and was recommended by a friend of mine. So I kind of put a lot of faith in what he said. However, I've been doing a lot of thinking about this project, and the more I think about it, the more I think I can overcome these problems. If the engine does need to be rebuilt, so be it. I can ride it as it is now and fix the engine when it dies. Or if I get the confidence later in the project, I'll try to fix it myself.

I did a compression test to the best of my knowledge today. The results are below. I doubt my numbers are great (but I don't know what they mean right now) but hopefully a new gasket could improve them, rather than a engine rebuild so early on in the project.

So here's some more shots of the major areas.





Collector is in a bad way. Probably need to replace the whole exhaust system.



This muffler is crap. It's almost falling off and will need to go obviously.



The number 1 header doesn't look great, I'd say with a lot of scrubbing it'd probably break through. Never mind, as I said, the exhaust system is going.





The internals of the tank aren't bad. Obviously the external has had a ding and there's a bit of bondo/bog in it. Again, not a problem as I'd eventually love to put a BCR whale on there if it'll fit a 400 and I can save the money up.





The choke lever is really loose. You can see where I've zip-tied the fuel hose on as it was super loose. The other zip-tie is the other end of the fuel hose connected to the carburetor. This is obviously temporary just to see if it started.





How would I clean the surface of the engine and other aluminum parts? Bead-blast? Sand-blast? Wire-brush and elbow grease? Can I remove the scaling and use a high temperature paint like Doug did for his 550?





Front brake. Needs some attention. As to the spokes. The rim itself seems solid but I'll know for sure when I get the rubber off and see what the insides look like.



Read drum. I need to see what the inside looks like. It functions ok if you push the pedal down hard.



I'm not sure why the chain guard was chopped like that.







Need a new bucket for sure.



The left gauge bucket is dented, the right is ok.





Scary. The rust on the rear fender won't matter as I'll throw that away. I'll need a new seat pan, air filter and rewire it. Strangely, I'm not scared be the electrics as that's one thing I'm confident with because of my computing background.



Ok so today... I went about testing the compression of the cylinders. I borrowed a tester from my local mechanic, took out the spark plugs and held the tester hard up against the hole. Then I gave it a few good kick's of the kick starter and read the measurements. I replaced the spark plug for each cilynder as I moved to the next one. Here was the mode number for each cylinder:

Cylinder 1: 75psi
Cylinder 2: 75psi
Cylinder 3: 50psi
Cylinder 4: 75+psi

Both my Haynes and Clymer manuals are still in the mail from the US, so I'm not sure what this data means. I'm assuming it's not good news.

The number 4 cylinder result (pictured above) actually got close to100psi on the first kick but not after that. Interestingly enough this number 4 cylinder's spark plug had an extra washer and what looked like some minor threading on it (pictured below). This plug was by far the stiffest to remove.





Number 2 spark plug port. Lots of dirt in there.



Cylinder 3 spark plug. This cylinder had the lowest pressure of the 4 but the plug looked the same as the others.



Ok, today ended a little bit more positive. I got to see my inspiration. My friend Andy's 1971 CB250 restore project. He just got his original side-cover badges re-chromed, so they're yet to go on. Still, it's much prettier than mine!

So I'm taking my bike to another mechanic tomorrow. This guy is a local and of similar age to myself. So I'm not sure if he'll know a lot about old bikes (his little backyard shop had a lot of new bikes in it) but maybe he'll have the motivation to have a crack. He's located just down the road from me, so maybe he won't rip me off. At least I'll have a second opinion.

Once again, I appreciate everyone's input.

Thanks,
Rick.
 
#3 ·
Ok so that mechanic just looked over it. I was standing with him when he was going over it. He didn't start it or really even touch the bike. He said he works in a Honda shop, has owned Honda's for 20 years and was recommended by a friend of mine. So I kind of put a lot of faith in what he said. However, I've been doing a lot of thinking about this project, and the more I think about it, the more I think I can overcome these problems. If the engine does need to be rebuilt, so be it. I can ride it as it is now and fix the engine when it dies. Or if I get the confidence later in the project, I'll try to fix it myself.

I did a compression test to the best of my knowledge today. The results are below. I doubt my numbers are great (but I don't know what they mean right now) but hopefully a new gasket could improve them, rather than a engine rebuild so early on in the project.

So here's some more shots of the major areas.





Collector is in a bad way. Probably need to replace the whole exhaust system.



This muffler is crap. It's almost falling off and will need to go obviously.



The number 1 header doesn't look great, I'd say with a lot of scrubbing it'd probably break through. Never mind, as I said, the exhaust system is going.





The internals of the tank aren't bad. Obviously the external has had a ding and there's a bit of bondo/bog in it. Again, not a problem as I'd eventually love to put a BCR whale on there if it'll fit a 400 and I can save the money up.





The choke lever is really loose. You can see where I've zip-tied the fuel hose on as it was super loose. The other zip-tie is the other end of the fuel hose connected to the carburetor. This is obviously temporary just to see if it started.





How would I clean the surface of the engine and other aluminum parts? Bead-blast? Sand-blast? Wire-brush and elbow grease? Can I remove the scaling and use a high temperature paint like Doug did for his 550?





Front brake. Needs some attention. As to the spokes. The rim itself seems solid but I'll know for sure when I get the rubber off and see what the insides look like.



Read drum. I need to see what the inside looks like. It functions ok if you push the pedal down hard.



I'm not sure why the chain guard was chopped like that.







Need a new bucket for sure.



The left gauge bucket is dented, the right is ok.





Scary. The rust on the rear fender won't matter as I'll throw that away. I'll need a new seat pan, air filter and rewire it. Strangely, I'm not scared be the electrics as that's one thing I'm confident with because of my computing background.



Ok so today... I went about testing the compression of the cylinders. I borrowed a tester from my local mechanic, took out the spark plugs and held the tester hard up against the hole. Then I gave it a few good kick's of the kick starter and read the measurements. I replaced the spark plug for each cilynder as I moved to the next one. Here was the mode number for each cylinder:

Cylinder 1: 75psi
Cylinder 2: 75psi
Cylinder 3: 50psi
Cylinder 4: 75+psi

Both my Haynes and Clymer manuals are still in the mail from the US, so I'm not sure what this data means. I'm assuming it's not good news.

The number 4 cylinder result (pictured above) actually got close to100psi on the first kick but not after that. Interestingly enough this number 4 cylinder's spark plug had an extra washer and what looked like some minor threading on it (pictured below). This plug was by far the stiffest to remove.





Number 2 spark plug port. Lots of dirt in there.



Cylinder 3 spark plug. This cylinder had the lowest pressure of the 4 but the plug looked the same as the others.



Ok, today ended a little bit more positive. I got to see my inspiration. My friend Andy's 1971 CB250 restore project. He just got his original side-cover badges re-chromed, so they're yet to go on. Still, it's much prettier than mine!

So I'm taking my bike to another mechanic tomorrow. This guy is a local and of similar age to myself. So I'm not sure if he'll know a lot about old bikes (his little backyard shop had a lot of new bikes in it) but maybe he'll have the motivation to have a crack. He's located just down the road from me, so maybe he won't rip me off. At least I'll have a second opinion.

Once again, I appreciate everyone's input.

Thanks,
Rick.
 
#4 ·
A wire wheel can work wonders on the rust. I'd just rock the engine till she goes and maybe look around for another engine. Can any other small honda four squeeze into the frame? Though I have to say I think you got taken for 1000 on it and maybe it's just a expensive lesson to learn.
 
#5 ·
A wire wheel can work wonders on the rust. I'd just rock the engine till she goes and maybe look around for another engine. Can any other small honda four squeeze into the frame? Though I have to say I think you got taken for 1000 on it and maybe it's just a expensive lesson to learn.
 
#7 ·
Welcome to the party, friend.

Though you are self-admittedly not very mechanical, your slow and critical approach is smart. I'd only offer a small bit of advice taken from lessons I've learned the hard way after rescuing a few too many swamped bikes.

You are looking at a lot of money and, depending on your finances, a long project before you get that bike "right". The first mechanic probably wasn't bs'ing you.

In fact, you may find that most mechanics wouldn't touch it. Not because the bike is a terminal POS, but because there are so many things (both seen and unseen) that will need to be addressed that the cost of restoring it will far exceed the value of the bike. Any mechanic that has been around for a while knows the risks of taking on a restoration project. Too often, the owner loses interest or gets freaked out by the costs (parts,labor and storage remember) that he just dumps the bike on the mechanic. To this end, I'd be wary of any mechanic that would take on such a project; unless it was agreed beforehand that only a few major, specific issues were to be addressed.

Since you stated that you've ordered manuals, I assume you intend to take on a bit of the resto work yourself. Good. If you're patient, you'll learn a lot. Make friends with as many people as you can who know old bikes and take note of their tips, tricks and advice.

As far as this particular bike is concerned, the 400Four is a great little machine. One of these in a fine state of tune is nimble, fun and damn good looking. The problem is finding replacement parts. While not the rarest bike out there, you're going to find that getting some of the stuff you may need will get real expensive, real fast. Wait till you come across a decent stock 4 into 1 up for sale...

So, it seems like you have at least three choices:

1. Patch it together and run it as is till it dies. Okay, but you're still looking at $300-$400 (US, I don't know what that translates into in Oz dollars) in tires, cables, battery, brakes and other random expenses just to make it safely roadworthy. If you're the reckless type who doesn't mind riding around on dry-rotted tires with questionable brakes and worn out cables, maybe you'll spend $100 on a new battery, some plugs and an oil change (Go with God on that choice).

2. Take it to a mechanic for a top-end rebuild and do the rest yourself. Here you're looking at $300-$700, depending on how things look on the inside and how much you're willing to do (i.e. save some money by disassembling/assembling the motor on your own and only farm out the machine work--cylinder hone/bore, valve grinding, etc.) Remember, you'll still have to deal with the additional expenses from #1, above. EDIT: These numbers still don't reflect the further costs involved for cosmetics, i.e. seat, tank, rearsets/controls, bars, fenders, etc.

3. Save this bike as a parts bike and find another 400Four in better shape to ride/restore. With a caution added concerning buying a bike without a title (a.k.a. stolen?), decent bikes without paperwork can be found out there, and, given that you do have a title for this bike, you could do a frame swap. This is a thirty year old bike and having spares around can't hurt.

4. Part her out and recoup what you can.
 
#6 ·
Welcome to the party, friend.

Though you are self-admittedly not very mechanical, your slow and critical approach is smart. I'd only offer a small bit of advice taken from lessons I've learned the hard way after rescuing a few too many swamped bikes.

You are looking at a lot of money and, depending on your finances, a long project before you get that bike "right". The first mechanic probably wasn't bs'ing you.

In fact, you may find that most mechanics wouldn't touch it. Not because the bike is a terminal POS, but because there are so many things (both seen and unseen) that will need to be addressed that the cost of restoring it will far exceed the value of the bike. Any mechanic that has been around for a while knows the risks of taking on a restoration project. Too often, the owner loses interest or gets freaked out by the costs (parts,labor and storage remember) that he just dumps the bike on the mechanic. To this end, I'd be wary of any mechanic that would take on such a project; unless it was agreed beforehand that only a few major, specific issues were to be addressed.

Since you stated that you've ordered manuals, I assume you intend to take on a bit of the resto work yourself. Good. If you're patient, you'll learn a lot. Make friends with as many people as you can who know old bikes and take note of their tips, tricks and advice.

As far as this particular bike is concerned, the 400Four is a great little machine. One of these in a fine state of tune is nimble, fun and damn good looking. The problem is finding replacement parts. While not the rarest bike out there, you're going to find that getting some of the stuff you may need will get real expensive, real fast. Wait till you come across a decent stock 4 into 1 up for sale...

So, it seems like you have at least three choices:

1. Patch it together and run it as is till it dies. Okay, but you're still looking at $300-$400 (US, I don't know what that translates into in Oz dollars) in tires, cables, battery, brakes and other random expenses just to make it safely roadworthy. If you're the reckless type who doesn't mind riding around on dry-rotted tires with questionable brakes and worn out cables, maybe you'll spend $100 on a new battery, some plugs and an oil change (Go with God on that choice).

2. Take it to a mechanic for a top-end rebuild and do the rest yourself. Here you're looking at $300-$700, depending on how things look on the inside and how much you're willing to do (i.e. save some money by disassembling/assembling the motor on your own and only farm out the machine work--cylinder hone/bore, valve grinding, etc.) Remember, you'll still have to deal with the additional expenses from #1, above. EDIT: These numbers still don't reflect the further costs involved for cosmetics, i.e. seat, tank, rearsets/controls, bars, fenders, etc.

3. Save this bike as a parts bike and find another 400Four in better shape to ride/restore. With a caution added concerning buying a bike without a title (a.k.a. stolen?), decent bikes without paperwork can be found out there, and, given that you do have a title for this bike, you could do a frame swap. This is a thirty year old bike and having spares around can't hurt.

4. Part her out and recoup what you can.
 
#9 ·
The CB400 Four is a neat little bike. It's a good first bike for a new rider. Easy to handle, smooth, reliable, and not so much power that you'll get into trouble. And as a bonus, they're worth keeping even after you outgrow them, just because they look good and are somewhat collectible.

Now, let's have a look at the bike that followed you home. Hmm. [pause] Well, Rick, there's no nice way to say it: that bike is a dog. It's worn out in just about every place that it's possible for a bike to be worn out. Brakes, suspension, exhaust, finish, just about everything needs to be rebuilt or replaced. Spokes and fenders are too rusty to be restored. Worst of all, the motor is worn out too, if those compression readings are correct.

So what to do? Well, you can just jump straightaway into a complete resto project. A full resto costs cubic dollars (at least US$2500 if you do all the work yourself, and probably much more). It will make the AUS$1000 (US$781) you paid for the bike seem like a drop in a bucket. A full resto would be a good choice if you really want to learn how to restore a bike, and you've got the money and time to do it. A lot of people would tell you to avoid a full resto on your first bike. They mean well. But they are also condescending to you. There is glory in bringing a clapped-out dog back from the ragged edge and making it shine again.

The other option is to sell (or part out) this bike and buy another one. You could buy a decent 400 Four for far less than a full resto would cost you. Or you could get a good running CB350 or CB450. Those are much easier bikes for you to make a cafe racer out of.

Edit: Sorry, I didn't see Krap's reply before I posted. He already told you what you need to know.
 
#8 ·
The CB400 Four is a neat little bike. It's a good first bike for a new rider. Easy to handle, smooth, reliable, and not so much power that you'll get into trouble. And as a bonus, they're worth keeping even after you outgrow them, just because they look good and are somewhat collectible.

Now, let's have a look at the bike that followed you home. Hmm. [pause] Well, Rick, there's no nice way to say it: that bike is a dog. It's worn out in just about every place that it's possible for a bike to be worn out. Brakes, suspension, exhaust, finish, just about everything needs to be rebuilt or replaced. Spokes and fenders are too rusty to be restored. Worst of all, the motor is worn out too, if those compression readings are correct.

So what to do? Well, you can just jump straightaway into a complete resto project. A full resto costs cubic dollars (at least US$2500 if you do all the work yourself, and probably much more). It will make the AUS$1000 (US$781) you paid for the bike seem like a drop in a bucket. A full resto would be a good choice if you really want to learn how to restore a bike, and you've got the money and time to do it. A lot of people would tell you to avoid a full resto on your first bike. They mean well. But they are also condescending to you. There is glory in bringing a clapped-out dog back from the ragged edge and making it shine again.

The other option is to sell (or part out) this bike and buy another one. You could buy a decent 400 Four for far less than a full resto would cost you. Or you could get a good running CB350 or CB450. Those are much easier bikes for you to make a cafe racer out of.

Edit: Sorry, I didn't see Krap's reply before I posted. He already told you what you need to know.
 
#11 ·
Although I'd have to agree that $1000 is a bit steep for a bike in that condition, CB400's are getting pretty rare over here in Oz - and you'd be hard pressed to find a complete one in ANY condition most of the time...

About your compression testing - you might have an inaccurate reading if you have just used the kickstart. Ideally you should pull all the plugs and do one cylinder at a time with the electric start (for about 4 or 5 seconds). Also, the rings are probably gummed up, so this will affect the reading to a degree (squirt a teaspoon of oil in there for the compression test).

Anyway, if I were you I'd get a new battery, clean the carbs, flush the fuel and try to get it running. That way you'll (hopefully) have a running bike, and if it gets too much and you decide to sell, you will be in a much better position to re-coup your money.

Good luck with it ;)
 
#10 ·
Although I'd have to agree that $1000 is a bit steep for a bike in that condition, CB400's are getting pretty rare over here in Oz - and you'd be hard pressed to find a complete one in ANY condition most of the time...

About your compression testing - you might have an inaccurate reading if you have just used the kickstart. Ideally you should pull all the plugs and do one cylinder at a time with the electric start (for about 4 or 5 seconds). Also, the rings are probably gummed up, so this will affect the reading to a degree (squirt a teaspoon of oil in there for the compression test).

Anyway, if I were you I'd get a new battery, clean the carbs, flush the fuel and try to get it running. That way you'll (hopefully) have a running bike, and if it gets too much and you decide to sell, you will be in a much better position to re-coup your money.

Good luck with it ;)
 
#13 ·
Hi all,

Thanks so much for the great feedback guys. This has already been a tremendous help.

@ krapfever: You've hit the nail on the head there. This local mechanic seems like a nice guy. I dropped the bike off to him this morning with the instructions to look it over, get it running and let me know his opinion on the life left in the engine. I said I didn't want it rebuilt or anything, only to let me know what it would cost to get the engine back to tip-top shape. So hopefully that gives me an informed opinion and some piece of mind. I might even be able to contra him a website for his labor, which would be nice. I can build one of those a lot better than I could an engine.

@ steve barker: You've given me some confidence. For better or worse, I'm an optimistic person and I think I can do this. At least if I can get through it, I'll know I'll be one happy camper with a bike I'm %100 sure I'll love. I can't imagine having anything else right now. I'm just in love with the 4-into-1 for some reason. 400cc might be a bit small for me after some more experience, but right now it's more than enough. I was fortunate enough to have a new Triumph Thruxton 900 for two weeks (a perk for running a magazine) and that thing, whilst very cool, was too heavy and scary for me.

@ hillsy: I'm so stoked to hear another Australian's opinion on the CB400F. After looking for one of these for quite a while, I formed the same opinion as you. So far, they just haven't been easy to find in Australia. That's why I've been so reluctant to get rid of this thing. Yeah, I think $1000 was too much to pay for it, but it was the roll of the dice I took buying a bike unseen from interstate. I was prepared for the risk. But from my research when looking into getting a bike, I just never saw anything decent sell on ebay, bikepoint, bikesales, gumtree or the trading post for less than a thousand. So whilst I might have been able to talk the guy down to say, $650, I wasn't prepared to drive 24 (12 there, 12 back) hours to do it. I'm ok to live with that extra $400 cost.

I'll let you all know how the bike comes back from the mechanic. I'm optimistic but not expecting big things.

Thanks again to everyone for their support!

Rick.
 
#12 ·
Hi all,

Thanks so much for the great feedback guys. This has already been a tremendous help.

@ krapfever: You've hit the nail on the head there. This local mechanic seems like a nice guy. I dropped the bike off to him this morning with the instructions to look it over, get it running and let me know his opinion on the life left in the engine. I said I didn't want it rebuilt or anything, only to let me know what it would cost to get the engine back to tip-top shape. So hopefully that gives me an informed opinion and some piece of mind. I might even be able to contra him a website for his labor, which would be nice. I can build one of those a lot better than I could an engine.

@ steve barker: You've given me some confidence. For better or worse, I'm an optimistic person and I think I can do this. At least if I can get through it, I'll know I'll be one happy camper with a bike I'm %100 sure I'll love. I can't imagine having anything else right now. I'm just in love with the 4-into-1 for some reason. 400cc might be a bit small for me after some more experience, but right now it's more than enough. I was fortunate enough to have a new Triumph Thruxton 900 for two weeks (a perk for running a magazine) and that thing, whilst very cool, was too heavy and scary for me.

@ hillsy: I'm so stoked to hear another Australian's opinion on the CB400F. After looking for one of these for quite a while, I formed the same opinion as you. So far, they just haven't been easy to find in Australia. That's why I've been so reluctant to get rid of this thing. Yeah, I think $1000 was too much to pay for it, but it was the roll of the dice I took buying a bike unseen from interstate. I was prepared for the risk. But from my research when looking into getting a bike, I just never saw anything decent sell on ebay, bikepoint, bikesales, gumtree or the trading post for less than a thousand. So whilst I might have been able to talk the guy down to say, $650, I wasn't prepared to drive 24 (12 there, 12 back) hours to do it. I'm ok to live with that extra $400 cost.

I'll let you all know how the bike comes back from the mechanic. I'm optimistic but not expecting big things.

Thanks again to everyone for their support!

Rick.
 
#15 ·
Hi, I'd like to put my 2 cents in too.The numbers on your compression test don't seem right, normal compression should be 135-145 psi.When doing a compression test the procedure is, remove all sparkplugs, hold throttle wide open,or remove carbs,and crank motor the same nomber of revs. for each cylinder. Your 75 psi was probably because the throttle was closed? also squirt some oil in each cylinder, spin the motor a few times and re-test all cylinders,you should get a slightly higher reading.If not, the low cylinder is bad.Since you have little to loose, try to re-torke the head bolts then re-adjust the valves. You might just get lucky! If so PLEASE do the brakes,wheel bearings,steering bearings and new tires,your life is worth it. THe bearings just take cleaning and new grease,or you could get new for under$100 for all. tires and brake parts are not expensive and common to most midsized Hondas from this period.When you get the service manual it will show how to do all of this, if you realy want to do old bikes you need to learn to do this stuff yourself. Maby fixing this old bike is just the learing tool you need, or maby it's not.you have to decide? good luck!
 
#14 ·
Hi, I'd like to put my 2 cents in too.The numbers on your compression test don't seem right, normal compression should be 135-145 psi.When doing a compression test the procedure is, remove all sparkplugs, hold throttle wide open,or remove carbs,and crank motor the same nomber of revs. for each cylinder. Your 75 psi was probably because the throttle was closed? also squirt some oil in each cylinder, spin the motor a few times and re-test all cylinders,you should get a slightly higher reading.If not, the low cylinder is bad.Since you have little to loose, try to re-torke the head bolts then re-adjust the valves. You might just get lucky! If so PLEASE do the brakes,wheel bearings,steering bearings and new tires,your life is worth it. THe bearings just take cleaning and new grease,or you could get new for under$100 for all. tires and brake parts are not expensive and common to most midsized Hondas from this period.When you get the service manual it will show how to do all of this, if you realy want to do old bikes you need to learn to do this stuff yourself. Maby fixing this old bike is just the learing tool you need, or maby it's not.you have to decide? good luck!
 
#16 ·
I've seen a bit of cb400 stuff around wreckers in sydney. If your keen ring around up here.

Silly but unbelievable how often i run into this, make sure the nuts on-top of your engine are tight. Have a mate with a 550 and every-time we service the thing the compression is low, turned the engine over and i noticed some washers dancing!

Also, is the gasket really gone? Or is it weeping oil? Its obviously not good, but least you could ride around until you get some more moolah for a rebuild of new donk...

Oh and wd-40 is american!
 
#17 ·
I've seen a bit of cb400 stuff around wreckers in sydney. If your keen ring around up here.

Silly but unbelievable how often i run into this, make sure the nuts on-top of your engine are tight. Have a mate with a 550 and every-time we service the thing the compression is low, turned the engine over and i noticed some washers dancing!

Also, is the gasket really gone? Or is it weeping oil? Its obviously not good, but least you could ride around until you get some more moolah for a rebuild of new donk...

Oh and wd-40 is american!
 
#18 ·
Hi guys,

More bad news today. So I took the bike to that local mechanic. He looked over it yesterday and today. He said he got it running, covered the holes in the exhaust with some rags and said 'he could hear a big end noise'. I've been told that is bad. I said to him, 'well how long until it stops working?', he said 'you could be lucky and it'll last another 6 months but it's getting louder'. He said he doesn't think it'd be worth doing the rest of the bike up with that engine. He said he thought my options were to part the bike, or buy a second hand engine to replace mine.

So, how bad is a 'big end noise', how hard is it to fix on my own, what would it roughly cost to get someone to do it and how much long could I expect the engine to run? I know these are all very dependent on a lot of variables, but I had to ask.

Interestingly enough, I called the guy that sold me the bike and told him that the bike was at the mechanics getting the engine looked at. He said that I shouldn't need to get the engine fixed as it was 'a good runner'. I wonder why he stick to his guns even after he'd sold me the bike? Weird.

A bit sad today.

Rick.

@ oldhondacafe: Thanks for the help. I knew I didn't do that test right, it was a lot of guess work as I don't have the manuals yet and knew I'd be taking it to the mechanic later that day anyway. As for all the brakes, wheels etc. Oh yeah, it's a death ride right now. There's no way I'd ride it more than now the driveway right now. I'll ask the mechanic about the head-bolts and valves. Maybe I could do some of those things to keep it on the death bed for a little while longer?

@ Big Bad Bob Dog: The thing is, it hasn't leaked a drop. So I'm not sure about the head gasket. I guess I'd have to take a look and see, but I'm loath to even touch the engine if I don't have to. I'd rather take your approach, ride it 'till it dies then fix it. But is it worth doing the rest of the bike up only to have the engine a POS? I don't know.
 
#19 ·
Hi guys,

More bad news today. So I took the bike to that local mechanic. He looked over it yesterday and today. He said he got it running, covered the holes in the exhaust with some rags and said 'he could hear a big end noise'. I've been told that is bad. I said to him, 'well how long until it stops working?', he said 'you could be lucky and it'll last another 6 months but it's getting louder'. He said he doesn't think it'd be worth doing the rest of the bike up with that engine. He said he thought my options were to part the bike, or buy a second hand engine to replace mine.

So, how bad is a 'big end noise', how hard is it to fix on my own, what would it roughly cost to get someone to do it and how much long could I expect the engine to run? I know these are all very dependent on a lot of variables, but I had to ask.

Interestingly enough, I called the guy that sold me the bike and told him that the bike was at the mechanics getting the engine looked at. He said that I shouldn't need to get the engine fixed as it was 'a good runner'. I wonder why he stick to his guns even after he'd sold me the bike? Weird.

A bit sad today.

Rick.

@ oldhondacafe: Thanks for the help. I knew I didn't do that test right, it was a lot of guess work as I don't have the manuals yet and knew I'd be taking it to the mechanic later that day anyway. As for all the brakes, wheels etc. Oh yeah, it's a death ride right now. There's no way I'd ride it more than now the driveway right now. I'll ask the mechanic about the head-bolts and valves. Maybe I could do some of those things to keep it on the death bed for a little while longer?

@ Big Bad Bob Dog: The thing is, it hasn't leaked a drop. So I'm not sure about the head gasket. I guess I'd have to take a look and see, but I'm loath to even touch the engine if I don't have to. I'd rather take your approach, ride it 'till it dies then fix it. But is it worth doing the rest of the bike up only to have the engine a POS? I don't know.
 
#21 ·
I do not agree that this procedure is correct or valid

however, I would think I'd want to know what the bottom end noise was. Was the engine oil contaminated with fuel? Those 400F's are hard to kill.

quote:Originally posted by oldhondacafe

Hi, I'd like to put my 2 cents in too.The numbers on your compression test don't seem right, normal compression should be 135-145 psi.When doing a compression test the procedure is, remove all sparkplugs, hold throttle wide open,or remove carbs,and crank motor the same nomber of revs. for each cylinder. Your 75 psi was probably because the throttle was closed? also squirt some oil in each cylinder, spin the motor a few times and re-test all cylinders,you should get a slightly higher reading.If not, the low cylinder is bad.
 
#20 ·
I do not agree that this procedure is correct or valid

however, I would think I'd want to know what the bottom end noise was. Was the engine oil contaminated with fuel? Those 400F's are hard to kill.

quote:Originally posted by oldhondacafe

Hi, I'd like to put my 2 cents in too.The numbers on your compression test don't seem right, normal compression should be 135-145 psi.When doing a compression test the procedure is, remove all sparkplugs, hold throttle wide open,or remove carbs,and crank motor the same nomber of revs. for each cylinder. Your 75 psi was probably because the throttle was closed? also squirt some oil in each cylinder, spin the motor a few times and re-test all cylinders,you should get a slightly higher reading.If not, the low cylinder is bad.
 
#23 ·
honestly, ride it till she blows up. In the mean time, hunt around for an engine. The best way to keep it registered without a problem, is to find another 400, and swap out everything except the crank case. The engine number is stamped in, so it would be the same ect. But if not, screw it. On that frame i'm sure you can go to a 650 four. Look all over aus, even in new zealand, because buying something thats half decent plus transport, is sure too cost less than rebuilding one of those old things.


Have to agree with hacksaw. Hard to kill a honda four.
 
#22 ·
honestly, ride it till she blows up. In the mean time, hunt around for an engine. The best way to keep it registered without a problem, is to find another 400, and swap out everything except the crank case. The engine number is stamped in, so it would be the same ect. But if not, screw it. On that frame i'm sure you can go to a 650 four. Look all over aus, even in new zealand, because buying something thats half decent plus transport, is sure too cost less than rebuilding one of those old things.


Have to agree with hacksaw. Hard to kill a honda four.
 
#25 ·
Big Bad Bob Dog,

It's funny how I only hear what I want to hear, especially when it's about this bike, but 'ride it till she blows up' is exactly how I'm thinking right now!

I've got a few days until I pick it up from the mechanic, so at least I can think about what I'm going to do.

Thanks for the encouragement,
Rick.
 
#24 ·
Big Bad Bob Dog,

It's funny how I only hear what I want to hear, especially when it's about this bike, but 'ride it till she blows up' is exactly how I'm thinking right now!

I've got a few days until I pick it up from the mechanic, so at least I can think about what I'm going to do.

Thanks for the encouragement,
Rick.
 
#27 ·
they always look better in the ebay pics. i know from experience. i've been working on a cb350 for almost two years, that required an engine teardown etc. in saying that i've had a lot of fun doing it, and learnt a lot. I paid about $800 for mine, which is a lot compared to US prices, but its condition was probably about the same as yours, and hard to find one for sale nearby, so i was prepared to pay a premium for it.
it's amazing how much better it will look when you remve the rust and corrosion.
as hillsy said, finding another parts bike would be quite hard, but it will most likely be your cheapest option long term imo. try and join the victorian VJMC yahoo group mailing list, and see if anyone has a rolling chassis with motor in it they're prepared to sell. don't need to worry about engine numbers if it's from the same model, unless the engine is stolen of course.

Liam
 
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