[46lukasz]

Hello Gentlemen!

My name is Lukasz, I'm from Poland but i have been living in Ireland for about 14 years now. I am happy to join this community full of knowledge

Recently I became a very happy owner of a Honda CB750F Super Sport (DOHC variant).

It has 32'000 miles /51'000 km on the clock. Engine is running, everything is functional for the most part and the bike is stock as far as I am aware, maybe apart from the exhaust.

I bought it in Northern Ireland which is governed by the UK and I registered it in Ireland for free. The vehicle import tax was zero because its a vintage vehicle.
It came with a stack of MOT's (which is like a yearly vehicle road-worthiness test in the UK), one for every year since new so the history is there which is nice.
The seller was visibly sad to see it go, with his eyes actually watering. It seems fairly well looked after and I even got a workshop manual with it from the guy.

I still have a few bits to do here and there before I put it on the road. I would like to document all the things here and get input and opinions from you guys. Should I put everything in this thread or start a new one under the 'Project Bikes' category?

Kind regards,
Lukasz

 

[seanbarney41]

Congrats! That is a beauty! And you know it's a good one when the seller crys...You can make him smile again by taking good care of it.

 

[46lukasz]

Hello guys,

I wanted to continue the thread to ask some questions as well as to give you a brief summary of what i have done on the bike so far, and get your opinions and advice if i should do something else or differently.

If this is the wrong place for this kind of thing i kindly ask the admins to move the thread to the correct category (eg. project builds).

I may write quite a lot to keep the write-up detailed, so a lot of people probably won't read the whole thing. So I will put all my questions that i may need help with, in a list at the end.



Identifying the bike:
First of all, I would like your help at identifying exactly what year and model the bike and/or engine is.
The documents say it is from 1983, however to my knowledge the DOHC F model stopped production in 1982. In 1983 they produced the Custom and Nighthawk models.
I thought that maybe its some kind of European version which was produced in 1982 but sold from 1983 in Europe, but i am not sure about this. Maybe the year in the book is first registration not production.
To add to the confusion, on a few of the yearly MOT road worthiness tests from the bikes time in the UK, it states that it is from 1982.
Another confusing thing is that I have single piston calipers at the front, which according to *this* website means that it is a 1981 model, because bikes from 1982 had dual piston calipers.

I hope that by giving the VIN someone will be able to precisely tell me which year is the bike from and what model it is.
VIN Number: RC04 2205000
Engine Number: RC04 E2209816

According to *this* website, RC04 is definitely pointing to a CB750F but then another letter after the F indicates the year of production. A= '80, B='81, C='82. I would really like to find out what bike I actually have.



What I have done so far:

Starter Motor Clutch
So the first thing I did when I got home from the seller is I let the bike warm up and gave it a more thorough look around to spot things i may have missed.

Then I realised that there is a clunky knocking sound coming from the left engine cover. It turned out that one of the spring loaded metal cylinders from the starter motor clutch assembly, fell out of place was knocking about.
It's the thing indicated on the picture below:

I have no idea how it managed to get out of its place but its fixed now and the bad sound is gone.
The clutch itself is a really nice system, simple but clever, only allows free rotation in one direction, while grabbing the shaft when rotated the opposite way, in order to turn the motor over when starting.
If it gives trouble in the future, there is the mod where you can use the starter motor clutch assembly from an R6 as it fits perfectly as shown in this YouTube video:
www.youtube.com/watch?v=sYJSUiXDim8



Oil Change and Filter Casing O-Ring
Then the next thing I noticed is that there was oil leaking from the oil filter casing. I planned to do an oil change anyway so I ordered a new oil filter which was K&N 401.
I read somewhere among amazon reviews that the o-ring that they include is too thin and may still leak so I ordered another one separately off eBay, and it indeed was much thicker than the one included with the K&N filter so I used that one.
Its the one from*this* link and I can recommend it to those that have this problem.

The old Oil filter was used up because it came out pretty much black. The seller said that there was an oil change done recently but that may not mean he changed the filter together with the oil.
The important thing was that I didn't see any metal shavings anywhere during the oil/filter change which is a good sign.
The oil I used was Castrol Power1 which is semi synthetic. (not the Power1 Racing version which is fully synthetic). Its 10W40 like suggested in the manual and has the JASO MA-2 specification.
From what I read, oils with this specification are suitable for bikes where the engine, clutch and gearbox are lubricated by the same oil, and oils without this specification can cause clutch slippage, which a lot of people warned about during my research about this.

The previous owner also did something strange here. When changing the filter you should put a spring (part #12) followed by a washer (part #11) followed by the new filter into the case in that order like shown on the picture.
In my case the washer is missing because they often get stuck on the old filter when its taken out and gets thrown to the bin.
The spring was actually placed on the outside of the filter case crushed between the case and the bolt (part #13) which was retarded.
I managed to bring it back into shape so that it actually puts pressure on the new filter but both the spring and washer will have to be bought new and replaced as part of next oil change.
This time around I used the stock oil drain plug bolt but as part next oil change I will install one with a magnet and safety wire it in. I have one bought but it came a in the post a few days after I did the oil change.

New Spark Plugs
I installed a new set of 4x NGK D8EA gapped to roughly 0.6-0.7mm, all according to the book. It really did make a difference when starting the engine, especially when cold.
Before it had a hard time and kept dying when cold. Even with full choke on, it needed a bit of throttle to keep it from dying until it warmed up.
With the new spark plugs it fires up no problem on full choke and then it can be steadily turned down until no choke at all is applied. Runs on all 4 cylinders without any problems.



Removed Rust from Tank
There was a lot of gunk and rust in the fuel tank. I needed to find a way of removing it. I found out that Hydrochloric acid (HCl) can work wonders based of a couple of YouTube videos and other forum posts online.
I bought some Ever Build 401 Brick & Patio Cleaner at 6Euros/5L it was a good deal. It has HCl in a concentration of about 10% w/w.
I first tested on a piece of steel with really good results:

So then I removed the tank and took off the fuel petcock so that the acid doesn't attack it. I used a finger of a rubber glove and some tape around the thread instead of a closed petcock and it worked fine.
I left the cleaner in the tank overnight and then emptied it out. A lot of nasty stuff came out, but it turned out that there was little rust but a lot of something that looked like scabs of resin. It probably was old petrol that has gummed up but I really don't know.
The rust was attacked straight away but those other things needed more shaking to remove and it still wasn't perfect.

After the acid was emptied from the tank, I neutralised it with water and baking soda, but before i rinsed all the water out to give it another rinse with fuel, I fell victim to flash rusting. The tank was then filled to the cap with fuel so that it doesn't rust any more.
Maybe in the future I will give this another go but rinse with fuel right away instead of water with soda to prevent the flash rusting from having a chance to happen.
The first picture above is the before state, the second picture is right after dumping out the acid. I didn't take a picture of the flash rusting.



Added an In-Line Fuel Filter
Even though I cleaned out the tank and the screen around the petcock tube, i installed an additional fuel filter and replaced some fuel hoses around the engine while I still had some hoses left.
Its clear so I can also see if fuel is flowing or not, and its an extra safety measure since some of the dirt from the tank may not have been rinsed out. I also installed some new shiny hose clamps while I had some left.

Fixed Crunchy Brake Lever
Another Problem I noticed was that the brake lever was crunchy. Its best described in the first 2 minutes of this video (great YouTube channel by the way):
www.youtube.com/watch?v=rB5yUOIZIoM
Its a dangerous one because the lever does not travel freely, but rather incrementally in steps so it's easy to go from light breaking into heavy breaking and you can wash out the front end.
All it took to fix it was some grease around the lever. I took it off completely and lubricated the hinge and also the part where the lever presses against the master cylinder. And the clicky operation was gone.



Replaced Shift Shaft Seal
I could see that there is an oil leak around the shift shaft but when I took the side cover off to get to the seal it was a horror story because of all the dirt mixed in with the leaking oil deposited around the shaft and the front sprocket.
I cleaned all of it up and took out the old seal. Interestingly enough it didn't have a circular spring around the inner diameter on the inside. It was replaced with a new one, Honda part #91204-425-003 and seems to be doing fine so far.



Other
Among other bits and pieces I did, I lubricated the tacho, speedo, throttle and choke cables.
This helped the tacho somewhat since the needle was jumping, it still does but much less now.

I also adjusted the chain tension to 20-25mm of slack according to the book.

I have ordered a new tyre, air filter and fork seals so I will be fitting them soon.
I wanted to repaint the forks with a fresh coat of black paint since I will have the front end disassembled. Currently it looks like the previous owner painted the forks using a paintbrush.
I am considering changing the front wheel bearings as well since I will have the front end disassembled, but that depends if there is any play in the current ones.
If i notice that the axle wobbles in the bearings when I take the wheel off, I will replace them, otherwise the current ones will stay.

Another problem I have is a stripped bolt in the left side engine cover. I am aware that these bolts are a Japanese standard driver bit, but I will try with a suitable Phillips head on a manual impact driver. Then I will replace all 3 bolts on that cover.

To Do List:

• Identify the exact model of machine
• Fix seized steering lock or get new ignition and swap over key lock barrel
• Replace front tyre and balance the wheel
• Sync carbs
• Check compression (out of curiosity)
• Inspect cylinders (I bought a small inspection cam that works with a phone, I'm curious how the cylinders look inside after all those years and milage)
• Replace air filter
• Replace fork seals (leaking is quite bad, leaks down the fork tube and onto brake disk on one side)
• Replace indicator relay (indicators flash but there is a suspicious high frequency clicky noise coming from the relay before they start working)
• Extract stripped bolt on on spark advancer cover and replace all 3
• Replace front brake pads
• Replace engine bolts with Allen head ones
• Fix hole in exhaust collector

Done List:

• Lubricate tacho, speedo, throttle and choke cables
• Replace shift shaft seal
• Replace oil filter and oil
• Remove rust from inside of fuel tank with HCl
• Lubricate brake lever
• Adjust chain tension
• Replace spark plugs

Questions:
1. When should I measure the oil level? Warmed up or cooled down engine? I am wondering because when you let the bike sit for a while all the oil drains down and it shows a higher oil level on the dipstick.
When you let the bike warm up the oil is distributed around the engine and it shows a lower level on the dipstick.
When you do an oil change you also warm it up first so that it drains better so should you wait for it to cool down before filling?
I am asking because when I poured in the new oil it was cold, it took 3.5L like it said in the book and it was up to the mark on the stick.
Next day I fired up the engine and checked again when warm, and it was too low so I ended up pouring 4L of oil in total into it, and now when cold its slightly above the max mark on the stick. Should I worry about overfilling by 0.5L more than recommended?


2. Some of the bolts on the engine are in bad shape and I am afraid that one day i will break the head on one of them and it will be impossible to take out. I would like to replace all engine bolts with new ones, specifically Allen head bolts.
I saw that there are engine kits available with all bolts needed. What is your opinion on those? is it easier to strip an Allen head or a standard hex head bolt? Because that is what i want to avoid.


3. When the engine was running I noticed that there is an opening in the exhaust, where the 4 separate pipes join at the collector and turn into one. There is a hole there because you can feel exhaust gasses when you put your hand near there.
Is that normal? If yes, what is its purpose? if not, should I weld it up or is it not a big deal?

4. I also want to replace the air filter. I took out the old one only to see some kind of liquid around the rubber gasket on the filter. Is is greasy but sticky at the same time, and smells similar to petrol or brake fluid. Its brown in colour too.
Initially I thought its some kind of way of creating a seal between the air filter and the gap for it inside the airbox, but I managed to put my hand into the airbox.
I find out that it is also coated with a similar sticky substance, even on the insides of the velocity stacks around the carb mouths inside.
What could this be? Is it normal or should I be worried that something bad is happening on the intake side?

5. Is it worth it to take the carbs apart and clean/rebuild them? The engine starts and runs no problem. Idles fine and climbs to high RPM without hesitation. Runs on all 4 cylinders without any problems.
I was thinking to leave it like that if it is good but maybe sync them or at least check how in sync they are. This doesn't involve taking them apart completely and is an easy adjustment if you have the gauges.

6. Is a jumping tacho needle a normal occurrence in these bikes or should it smoothly move up and down? Its still quite jumpy in my case.





I think this is everything I have to say so far. I hope that you all will enjoy my write up and I am open to all suggestions and comments.
Please also tell me what you think i should do to get this bike on the road in a safe condition, and what generally is worth doing or replacing on these bikes.

Kind regards,
Lukasz

 

[seanbarney41]

I don't know too many specifics for the dohc bikes but here are some answers...
1.I doubt .5 extra litres will harm anything but I would guess if you put in 3.5l cold and it came up right on the dipstick, that is gonna be right.

2.Allen or hex bolts are fine, just be aware that a 6mm bolt is very easy to strip the THREADS!...no big wrenches allowed!

3.The hole in your exhaust collector is not normal and serves no purpose. Weld it up or replace it or live with extra noise and sooty gases escaping. I doubt it will affect the running condition or performance of the bike very much.

4.I have seen similar goop on air filters before, not really sure what it is or where it comes from...my guess is gas fumes degrading the glue used to manufacture the air filter. Probably time for a new one.

5.My grandpappy told me, "If it ain't broke, don't fix it" and darned if he wasn't exactly right when dealing with these carbs...vacuum sync can be a good thing

6.Should move smoothly but the jumpiness can be a sign of imminent gauge death...or sometimes they smooth out with more use. These weren't really designed for easy service but many have done it successfully, and yeah many have royally fucked em in the attempt(me included)

Really, nice careful work so far but beware that fuel filter sometimes causes fuel flow problems. There should be a screen/sock on the fuel pickup inside the tank. If yours is intact, that filter is unnecessary.

 

[46lukasz]

Thanks for the quick reply to my questions.

I have updated the to do list on the first post to include the Allen engine bolts kit and fixing the exhaust hole, as well as syncing the carbs.

There was a filter as part of the fuel petcock, but I put the inline fuel filter in there as an additional safety measure especially after cleaning the rust out of the tank. If it gives me trouble with fuel flow i will remove it.

Kind regards,
Lukasz

 

[46lukasz]

Hi again guys,

Just another update, i forgot that i recorded some short videos of the bike running.
The first one was recorded when the bike was bought and the second one was recorded after i have done everything i wrote about so far. You can probably hear the difference in idling because the idle RPM was reduced to what it should be according to the book.
Enjoy!

https://www.youtube.com/watch?v=4xLjtX3GXjM
https://www.youtube.com/watch?v=Qs9fTcL07_g

Kind regards,
Lukasz

 

[46lukasz]

Hi guys,

So i have found out that the gunk on the air filter and inside the air box is coming from the crankcase ventilation system. I had a look on my bike and I found something funny, there is no catch box for this gunk underneath my battery and there should be one.
It is meant to be a regular maintenance step to empty this box once it fills up.
There is plenty of rust underneath the battery holder so maybe there was one there before but it's gone now. On the other hand, I don't see any hoses that would indicate that anything was there to start with.
So correct me if i am wrong but i think there are only two hoses involved in this crankcase ventilation system. One going upwards on the gearbox side and one going upwards on the clutch side.
Both of these on my bike are connected to a big T which in turn connects to the air box. That is it as far as I could see. I would appreciate if someone could post some pictures or diagrams of how its really meant to look.
Or maybe its region/model specific?

Another thing going back to trying to identify the actual model of the bike. I know for sure that in Ireland and UK, what's in the book is the year of first registration and not year of production, so I definitely shouldn't go by that, 1983 is wrong anyway.
According to this website
1979 VIN started with RC04-2000023
1980 VIN started with RC04-2100003
From 1981 onwards the VIN naming convention was different, eg: JH2RC040*BM200004

My VIN is RC04-2205000 which confirms that the bike is from 1980. However there is something else.
The same website says that the 79 model speedometer had a 150 mph (240 kph) limit while from 80 onwards it had a 85 mph (135 kph) limit.
My bike speedometer goes up to 240kph as if it was taken from a 79 bike.

I also know that the bike was repainted once (change in colour in the MOT documents and visible filler on the tank) so this would indicate that it was damaged.
My idea is that it originally had the speedo that went up to 135kph, but it was crashed at some point and the clocks were damaged and replaced with ones from 79.

If that is to be true, and it all adds up, it then is exactly a CB 750F-A


In the mean time, I'm preparing to take off the front wheel and forks to replace the tyre and fork seals. I have build a stand that props up against the engine cover crash bars and holds the front wheel off the ground.

Kind regards,
Lukasz

 

[TrialsRider]

Just a suggestion; if you have a strong overhead structure or even engine hoist? is generally a lot safer and easier to hang a bike then prop it up on stuff imo.
... I almost suggested Deer or Moose hoist but I bet they don't do a lot of big game hunting in Ireland.

 

[TrialsRider]

lol let me rephrase that

 

[TrialsRider]

oh and yes,
your crankcase will spew whatever stuff gets by the piston rings and valve guides along with a little oil mist which is pretty much typical of any engine,
ventilation is very significant on a single cylinder engine, singles pretty much move their displacement of in/out air plus blow by gases through the crankcase on every stroke.

... is very nasty environment inside an engine and the older the engine gets the more disgusting it is. My airbox typically collects relatively clean engine oil in it which is a good sign, if it was black with soot, contained water or smells rich with gasoline, those are probably not such good signs.

 

[46lukasz]

Hi again guys!

Thanks TrialsRider for the suggestion, its a good idea but unfortunately I don't have a hoist of that kind.
The stand was put together with screws though, and a week later the bike is still up on it so i guess its doing its job.

Thanks for explaining the ventilation system for me in more details. I don't think that the gunk in the air box was sooty or contained water so it should be good.
Could you explain why smell of gasoline in the ventilation system is a bad sign?

As an update, I have taken the wheel off, got the new tyre fitted and cleaned up the front rim a little.
I went with the Avon RoadRider tyre because it was reasonable price, availability for that rim size was good, and it matches the rear tyre that was put on by previous owner and is still in very good condition.

By cleaning up the front rim I mean I took some sand paper and took off the grime and oxidation from the edges where the stamped spokes were silver.
The result isn't much of a difference and i think it was a bit of a waste of time, but then again all the small details like that add up to the overall effect.
Before and after:

I have also taken off the front forks and I plan to do the seals next. I bought a new air filter and a fork seal kit from a local motorcycle shop.
Unfortunately when I got home i noticed that the kit is incomplete as it has 2 dust seals but only one fork seal. The shopkeeper was very nice and helpful about it though and he already posted the missing seal to me.




In case someone is going to do a fork rebuilt, the kit is an AllBalls part number 56-115, or if you want to buy separately the dust seals are AllBalls part number 36-1013 and the oil seals are AllBalls part number 35-1011.

I had another look after the crankcase ventilation system on the bike and in the manuals and i am still kind of confused about it.
I found there 2 pictures in the manual. Both show the drain tube that doesn't exist on my bike or I must be blind.

What I did find was a drainage tube at the bottom of the airbox. That tube just goes to the side and by the swingarm there its open and the stuff can drain onto the road

I found another diagram where I have indicated with green the two main hoses coming from the crankcase and connecting through a big T joint with the airbox at the top of it, and also the airbox drain that i mentioned above.
In red I indicated all the missing stuff.

Kind regards,
Lukasz

 

[TrialsRider]

...

Interesting :| a friend bought the same product for his bike from those people and he was also short by one fork seal. The parts in the slide bushing set they supplied were so far out of spec, I had to leave half the old bushings in service, but they do give you good stickers.


Gasoline smell in your engine oil is an indication of raw fuel getting past the piston rings, is pretty much the only way it can get in there (unless your intake valve guide is completely shot and your crankcase is trying to suck through anywhere it can), gasoline accumulated in the engine oil will eventually evaporate through and out of the crankcase breather once the engine gets hot. Drain tube on some of my bikes are very short but it will always be at the lowest point in the air box (storage tank on mine is part of the air box). The diagram you showed is a closed loop PVC positive crankcase ventilation system and the intent is to return and re-burn or collect most of the volatile gasses and burnt nasty stuff that is expelled from the crankcase as a result of combustion pressure blow-by past the piston rings.


Useless trivia: It's a pollution control feature now but closed loop crankcase ventilation was originally designed to make army tanks that could handle a deep water crossing.

 

[XB33BSA]

like trialsrider promotes gas in the oil is very harmful
it can happen with overflowing carbs
but you would have a warning sign in a
vhigher sump level from the time you changed the oil (if a greatr amount migrateddiown there) a simple test is try to light on fire the dipstick end ,very simple gasoline in the oil will make it easier to light on far
we are on fire here in the state of jefferson so be careful,please with fire

 

[46lukasz]

Hi again guys,

Thanks for your replies about the breather systems and fuel smell in oil. Before I actually changed the oil in the first post I had a hard time starting the bike and the plugs came out wet in fuel. However I didn't try to fix this and instead I changed the plugs and oil as part of the service. Started right up and I don't have any problems since. The old oil did smell like fuel though!

I have a few updates to share with you guys.

So with the stand for the bike ready and with the missing seal received in the post I could start working on the forks.

I took them off the bike and inspected the chrome slider bits. They had a few nicks in the areas where they are clamped to the steering assembly but the surfaces where the seals work were smooth and undamaged.

I had to fabricate a tool to unscrew the fork caps since I didn't have a 17mm hex key. I used a standard hex bolt head to which I welded a steel rod so that I have something to grab when turning it. It actually bent when I tried to take off one of the caps but it finally gave.

I then cleaned up the fork caps with a wire brush on an electric drill followed by some wet sandpaper.

Then I disassembled the forks completely and pulled out the old seals with a flat screwdriver. I could identify the bad seal that was leaking on the right side because it had a strange round hole defect on the top side and the spring was completely out of shape on the under side.

I then stripped the black paint off using a wire brush on an electric drill.

Next I spray painted them with two layers of etch primer and let it dry overnight. I left the fork oil drain plugs in place during the painting. If I will change the oil in the future I'll just clean them up to bare metal, but for now they will be black like the fork.

I also did a few other small bits and pieces in the meantime:

I installed a new indicator flasher relay.

A new rear tank rubber, because the old one was splitting into two and was held together with tape. You can see the old one laying near the battery.

I also put in a new ignition switch. It's not an original honda part but it was a bolt on job without any problems. Turning the key feels really good and clicky, and I finally have a working steering lock. The worst part is that I now have 2 separate keys. One for ignition and one for the fuel tank, but I'll have to live with that.

I finally put in a new air filter and I also bought a replacement oil filter spring. To go with that I also found a washer that is the exact size of the oil spring washer that I was missing.
Those will have to be put in on the next oil change though.

Kind regards,
Lukasz

 

[CaTacL1sm]

Good work!

It might be worth getting some electrical contact cleaner and cleaning/inspecting all of the connections as well

 

[CaTacL1sm]

While everything is apart, it would be worth upgrading the wheel bearings and stem bearings with All Balls ones

 

[46lukasz]

Hi guys,

Just for information, I bought all of the parts from the previous post at
https://www.partsnmore.com/parts/honda/
From what I can understand they are not original Honda replacement parts, but the quality is good and fitment is good.

CaTacL1sm I did clean up the contacts when swapping the ignition switch, and the rest of the electrics works 100%.

Is there a noticeable difference when the wheel and steering head bearings are changed to the AllBalls ones? I was considering this but the current ones are still very smooth and have no play or slack in them at all.

So I have spray painted the forks satin black now and I am really happy with how it turned out. You can still see the sand grain pattern from the casting of the part. I think it's real nice, especially when compared to brush strokes left on by the previous owner.

When the paint set I wrapped the parts in cling film so that I didn't damage them and I installed the seals. This was quite easy as I pressed the new seals in by hand as far as I could and then used the old seals and a plank of wood to hammer them in until I could see the groves for the locking ring to go in.

I then lubed the seals up and put the fork back together, including the dust seals.
The spring was still about 2cm longer than the minimum length allowed in the manual.
I filled the forks with 175ml of Castrol 10w grade fork oil each, like it says in the manual.
The new caps went on and I was really happy with the result.

I also have successfully extracted the bolt on the ignition timing cover. The head of it was rounded off. I bought a manual impact driver just for this one bolt and I was surprised what happened. I hammered the Philips bit into the rounded bolt head as far as I could, up to a point that it was stuck in the bolthead. This would prevent the bit from slipping when I use the driver and round the bolthead even more. So I did that and to my surprise, the bit shattered. I did the same with a flat bit and it also shattered on first use of the driver.
I was even more surprised because the hexagonal base on these bits is twice the size of your regular screwdriver bits, so I thought it's going to be solid but turns out it's just made out of chinesium.

I ended up drilling through the head of the bolt so that I could unscrew the remaining two bolts and take the cover off.
Unfortunately while doing that I nicked the inside of the bolt hole on the cover but it's very small and not visible when looking down at the bike.

I was left with the remains of the bolt stuck in the engine casing, but I redid the thread on it with a M5 die and the out in two nuts and countered them against each other. Then I could turn it like any other bolt and it came out. I also put an M5 tap through the bolt holes to clean up the threads and put copper grease on the new bolts to prevent that from happening again.

Overall I would like to polish this engine cover in the future and highlight the honda logo on it.

I also took the left engine cover off where the starter motor clutch is because I had to change the gasket, the old one was torn in two places. I also cleaned up the bolt heads with a wire brush and a drill before putting them back in place.

Kind regards,
Lukasz

 

[CaTacL1sm]

I think you've got tapered bearings already, but putting in a brand new set is good preventative maintenance. Same goes for wheel bearings.

Then again, I can go overboard with the "while you're in there" mentality

 

[XB33BSA]

Hi guys,

Just for information, I bought all of the parts from the previous post at
https://www.partsnmore.com/parts/honda/
From what I can understand they are not original Honda replacement parts, but the quality is good and fitment is good.

CaTacL1sm I did clean up the contacts when swapping the ignition switch, and the rest of the electrics works 100%.

Is there a noticeable difference when the wheel and steering head bearings are changed to the AllBalls ones? I was considering this but the current ones are still very smooth and have no play or slack in them at all.

So I have spray painted the forks satin black now and I am really happy with how it turned out. You can still see the sand grain pattern from the casting of the part. I think it's real nice, especially when compared to brush strokes left on by the previous owner.

When the paint set I wrapped the parts in cling film so that I didn't damage them and I installed the seals. This was quite easy as I pressed the new seals in by hand as far as I could and then used the old seals and a plank of wood to hammer them in until I could see the groves for the locking ring to go in.

I then lubed the seals up and put the fork back together, including the dust seals.
The spring was still about 2cm longer than the minimum length allowed in the manual.
I filled the forks with 175ml of Castrol 10w grade fork oil each, like it says in the manual.
The new caps went on and I was really happy with the result.

I also have successfully extracted the bolt on the ignition timing cover. The head of it was rounded off. I bought a manual impact driver just for this one bolt and I was surprised what happened. I hammered the Philips bit into the rounded bolt head as far as I could, up to a point that it was stuck in the bolthead. This would prevent the bit from slipping when I use the driver and round the bolthead even more. So I did that and to my surprise, the bit shattered. I did the same with a flat bit and it also shattered on first use of the driver.
I was even more surprised because the hexagonal base on these bits is twice the size of your regular screwdriver bits, so I thought it's going to be solid but turns out it's just made out of chinesium.

I ended up drilling through the head of the bolt so that I could unscrew the remaining two bolts and take the cover off.
Unfortunately while doing that I nicked the inside of the bolt hole on the cover but it's very small and not visible when looking down at the bike.

I was left with the remains of the bolt stuck in the engine casing, but I redid the thread on it with a M5 die and the out in two nuts and countered them against each other. Then I could turn it like any other bolt and it came out. I also put an M5 tap through the bolt holes to clean up the threads and put copper grease on the new bolts to prevent that from happening again.

Overall I would like to polish this engine cover in the future and highlight the honda logo on it.

I also took the left engine cover off where the starter motor clutch is because I had to change the gasket, the old one was torn in two places. I also cleaned up the bolt heads with a wire brush and a drill before putting them back in place.

Kind regards,
Lukasz

sweet bike !
on the alternator cxover
simple trick,on a cover or assembly that has only one last stuck bolt AND the part is not dowel located or registerl/precision centering ring
with only stuck screw remaing bump the cover in the direction of loosen screw
many times this will break loose a tough one
you would be smart using some heat on the aluminum to break her free
it helps to know for sure that delicate things be harmed easily, and dont crash the electrics

 

[46lukasz]

Hi again guys,

XB33BSA I tried to do that but because of the stuff underneath the cover I could not turn it all the way around with the one bolt stuck in. I had to jiggle it back and forth until it came off with the bolt that had the head drilled out remained. The heat would be a helpful thing as well but I was worried about different rates of expansion of the steel bolt and aluminium engine casing, in case I cracked it. Now I think i was being paranoid.

So i have now put the front end back together and I am quite happy with it. You can see the outcome on the pictures below.

I have installed new front break pads, I went with sintered Goldfren 079. They seemed so be a good deal with mostly good reviews and good price and good availability. They are also made in the EU so at least its not some Chinese pads.
You can see that the old ones were pretty much used up and also soaked with leaking fork oil so they had to be replaced.
Everything was cleaned up but now i see that i could have done a better job at the caliper brackets.
The calipers themselves could also use a new paint job but that requires heat resistant paint or preferably powder coating so maybe I'll do that in the future.

Overall the brakes should function very good and the caliper slider pins were re-greased so they should bite from both sides evenly.
The rubbers on the slider pins are old and look like they are lightly perished, but they are not cracked or ripped so they will do for another while.

Replacing the brake lines with new braided ones would also make a big difference. And make it a lot safer too - I don't feel too good about riding with 40 year old brake lines.
I was thinking about removing the brake line T connector that is mounted just below the horns, and instead of that to run a line from the lever pump to one of the calipers, and then a second line from the first caliper, over the fender and into the second caliper. That should look quite clean.

Once I put everything back together I noticed that the speedometer cable has a sleeve that doesn't want to go into place over the o-ring. Then I realised that it was actually rubbing against the spinning brake disc. It probably melted together into the cable itself and now there is no way of pulling it back to where it was meant to be. I think I will get a new speedo cable but I would be thankful if someone posted a picture of their bikes speedo cable just so I can see what its meant to look like.

I also replaced the grips on the bars. They aren't really from the correct era but I like the look of them and they make the bike younger. I also ordered simple black bar ends to go together with them.
Interestingly they were shorter than the original ones and the throttle tube is sticking out a small bit. I have to cut it off and move the whole thing together with the brake lever to the edge of the bar.
To put on the new grips I used compressed a air gun with a tube nozzle. I injected compressed air between the bar and the rubber grip with created a pillow of air between the two and the old grips slid off and new ones slid on very easy!
I highly recommend this method because there is no lubricant involved so the grips are on there solid and don't spin around, especially if you degrease the bar before hand.

I'm also thinking of installing new LED indicators in the future. That would look quite neat compared to these bulky original ones.

Also a new issue came up recently. I knew that the fuel tank was damaged at some point because I could see the bad filler job underneath the paint. But now it has started bubbling up so the tank is definitely going in for a respray in the future

Here is the updated to-do list.

To Do List:
sync carbs
figure out a way to have single key with new ignition
speedo cable
new brake lines
cut sticking out throttle tube
repaint fuel tank due to bubbling from under paint
Check compression (out of curiosity)
Inspect cylinders (I bought a small inspection cam that works with a phone, I'm curious how the cylinders look inside after all those years and milage)
Check valve clearance and adjust if needed
Replace engine bolts with Allen head ones
Fix hole in exhaust collector
check charging system by measuring voltage of battery at 3-4k RPM
install new oil filter spring and washer on next oil change

Done List:
Identify the exact model of machine: CB750FA 1980
Lubricate tacho, speedo, throttle and choke cables
Replace shift shaft seal
Replace oil filter and oil
Remove rust from inside of fuel tank with HCl
Lubricate brake lever
Adjust chain tension
Replace spark plugs
Replace front tyre and balance the wheel
Fix seized steering lock or get new ignition
Replace air filter
Replace fork seals
Replace indicator relay
Extract stripped bolt on on spark advancer cover and replace all 3
Replace front brake pads

That's it for now!

Kind regards,
Lukasz