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Discussion Starter #1
Been looking at getting a bike for awhile now, at first I wanted a newer gs500, sv650 or something like that. But I decided I wanted something I could make into a project, havent had anything to turn wrenches on for awhile and I'm starting to get withdrawals :D

Sooo today I went and looked at a 1980 cb750.
Here is the add...
"1980 cb750. it does run but needs the carbs cleaned( was sitting for sometime) It needs the ignition switch replaced or rekeyed the owner lost the key! it is a cheap fix, The plastic side covers are missing but they are avalible. The seat needs to be recovered. it needs a little TLC to make it a good daily rider. Remember this is a 29 year old bike, it is not perfect. It is a good project bike that doesnt need much. Also if you cant do the work yourself my shop can do it for you. Please call my cell"



As it says the previous owner lost the key... He was smart and didnt cut any wires though, the plug is just undone with some wires attached in there going to a switch so you can turn it over. I saw it run, needs some carb cleaning though, didnt want to idle on its own.
The seat I'm not worried about as I plan on replacing it anyways.
Gave it a good look over, probably been in arizona its whole life as I didnt see very much as far as rust at all.

So what does everyone think of it as far as a start for my cafe project? I can pick it up for 400. I talked to the guy at the shop that is selling it for somebody for awhile, he has been building cafe style bikes and bobbers and said he can help me out if I need it.

I also found a cx 500 that needs a speedometer cable and a master cylinder for 500 if I dont go this route.

Hopefully I can start posting pics of a half pulled apart and cleaned up bike soon lol

thanks
 

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well, you don't talk about your skill level so I am just going to assume that you can tell me what a wrench looks like and little else.

personally, it is a cb750c custom with the awful 16" rear comstar. Lousy bike to make a performance motorcycle out of since you have to first undo the factory's misguided attempt to appeal to the chopper market in the 1980s.

Any old bike you buy is going to be a project, you don't need to search out and look for trash. 20-30 years of use means shit gets worn out naturally. Go find the best example of one you can afford and start riding it.
 

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well, you don't talk about your skill level so I am just going to assume that you can tell me what a wrench looks like and little else.

personally, it is a cb750c custom with the awful 16" rear comstar. Lousy bike to make a performance motorcycle out of since you have to first undo the factory's misguided attempt to appeal to the chopper market in the 1980s.

Any old bike you buy is going to be a project, you don't need to search out and look for trash. 20-30 years of use means shit gets worn out naturally. Go find the best example of one you can afford and start riding it.
 

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Discussion Starter #8
quote:Originally posted by Geeto67

well, you don't talk about your skill level so I am just going to assume that you can tell me what a wrench looks like and little else.
I have done a decent amount of work to my cars, so im sure my skill level is fine for working on a bike.

Ok, I am looking around trying to find a nicer bike, not finding much though. :/
So what exactly is different about the 750 custom? The seat and bars could be replaced easily enough, but is the frame any different from the other models?
 

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if you are dead set on a DOHC cb750 then find a cb750F supersport from 1979-1982. These were the sporting versions of the same engine. The frame tubes are actually thicker on the SS. Plus you got Dual disc brakes in front and a disc rear, the better frame, a better set of trees with less rake, better forks, better styling, and all around a better motorcycle. This is the time period where honda began engineering and building specific bikes for specific kind of riding and not just selling different flavors of the same bike as they had been with the SOHC.

Are the customs frames different? well maybe - I don't remember if the race is any different but the C and K both have the thin wall frame tubes vs the Fs which have the thick wall. The suspension and brakes are unique to the C as it has a single comstar disc upfront and 16" comstar drum rear), plus slightly longer forks, and the crappy single piston calipers which you can't upgrade. furthermore the stock exhaust is heavy and I am not sure there are aftermarket C exhausts made anymore.

Honestly if you were to build a sporting motorcycle out of that and do it properly, the only parts you would keep are the frame and the engine. A cafe racer is not just a seat/tank upgrade, it is a performance motorcycle. As long as you haven't bought your bike yet you might as well get the best starting point as you can. If you want to stick to hondas of that era get the F, otherwise GS750s and KZ1000s from the same period are still cheap (provided you don't find their chopper versions the L and the LTD) and with the GS750 you can still get spokes up to 1979.

Usually this is the part where a bunch of us regulars troll craigslist in your area and find you a few better bikes in the same price range but since you have decided to be a smartass and put USA as your location I will just go out and say way to defeat yourself here pal.
 

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oh, and working on cars is not like working on bikes at all. In many ways it is easier and others it is much much much harder. Bikes from the 1970s and 1980s were rolling testbeds for technology that eventually made their way to cars (DOHCs, Fuel Injection, Turbos, 4 valve heads, etc....). If you are used to working on good ol' fashioned 'Merican V-8s then the first time you go to do a valve adjustment on a bucket and shim DOHC engine your mind is going to blow out the side of your head. Consequently if you are from the new school of fucking with FI cars the concept of carb rebuilding and tuning is going to throw you for a solid loop.
 

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the dohc 750 isnt a particularly bad bike... its just not gonna be a cafe racer... They are comfortable fairly quick bikes that do well with low bars and a different seat. They are heavy. I think the engine weighs almost as much as a entire cb350! With no fenders, seat, lights, battery (no it wont run without one nor does it have kickstart capability) it still weighed far in excess of 400 pounds. A K model can lend a rear spoke wheel and 82 C models had dual front discs. But you cant have spokes and dual front discs without using a hub off of something else as the DOHC K hub can only take one disc. Dual piston calipers are an easy upgrade from a cb900f (and C i think) (just make sure you get hangers from a fork without the antidive, calipers and hangers from a vt700 shadow work too). Stopping is still underwhelming but it will get the job done. Best thing is to swap on CBR forks and be done with it. The frame is weird beneath the tank and pretty much a tank has to be made for that frame or it doesnt fit.

The engine is somewhat maint. intensive. Unlike a SOHC 750 with adjusters, every valve adjustment costs money. Sometimes you can move shims around to get tolerable clearances, usually you end up having to buy atleast two. Either make friends with someone at a shop, order the shim starter kit, or be prepared to wait while shims come in the mail. You also need the tool to depress the bucket to remove the shim. And a micrometer to figure out the thickness of the shim you just removed. And a notebook and pencil. And you get to do this...alot...or else you get to remove the engine, then the head and pull 16 tiny valves and relap them and replace the burnt one(s).

All that being said I still like mine, alot. It is not a cafe bike, I may one day put a solo seat (if i ever find something that fits with that tank might just build one) but i will never call it a cafe bike. A fun bike, yes, worth it, yes but i have found i like working on bikes as much as riding them.


A CX eh...they are reliable (mostly, cams tended to wipe out in some) heavy liquid cooled bike. Definately less maintenance (IMHO) than the C but they are just strange. I have a love hate relationship with their looks. Sometimes I love the cylinders hanging out and the uniqueness of the design, other times they are gawky. If you search the board there is a very neat bike on here (i forget whose it is) and I think if you get a decent running one its certainly a viable project. Dont expect to build a groundbreaking wonderful perfect so clean you can eat off it bike the first go round. A dirty running fun bike that you can enjoy and work on trumps a pile of parts in the corner. :)

Oh and I think the frames between a C and F are pretty close to the same. The C has this dip where the rider seat is with the pillion up a curved section that ends in the rear fender/grab bar mount. I think to put a solo tail on one you would need to space this a bit.
 

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Raven,

C and F frames are different. Put one on a scale some time, it will shock you. They are hella different where the pegs mount as the F uses alloy plates to mount the foot controls and the C used steel welded to the frame (some have smaller alloy plates but are not interchangible). Also the F can be considered a cafe racer a la AMA superbike replica. Stock the bodywork was modeled after the tracy bodies of the 1970s.


I personally Hate CX500s just because they used to litter the NYC motorcycle landscape. There are people who like them though and a couple have built interesting...ahem...cafe bikes out of them. The problem with a CX500 is there are certain things that go bad which are not easy fixes (require striping the motor down to the block) and if you don't know what you are looking at it is really easy to buy a lemon of one. I wouldn't buy a project cx500, but maybe if a really really nice one came along I could be persuaded to ride it... for like an hour....and not set it on fire.
 

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yeah I knew about the peg issue, its pretty impossible to mount F parts on there. It has weird (read ugly) passenger peg mounts as well. C's are really alot more trouble than its worth to make into a cafe bike, which is why i gave up on it as a cafe bike. But it isnt a bad ride with the low bars (not clubmans, superbike bars which are as low as you can go without dealing with the peg issue in a very spark intensive way...) and one day I will probably put a solo seat/tail on it. But it still wont be a cafe bike IMHO, as it can never be distilled to its essence so to speak.

the cx's look like an absolute bitch to wrestle the engine in and out of! kind of like the square peg in a round hole arrangement. Wasnt it the cam or chain or something in that area that died on alot of these? I wouldnt mind having one as a beater, but it would have to be very very very cheap (like it runs and stops and doesnt burst into flames for <$200 or atleast doesn't burst into flames at inopportune moments <$175...)
 

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duh i just looked at a pic of the cx, it looks like the engine is part of the frame and doesnt have a tube beneath it. so it probably isnt so bad to get out!
 

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it is also pushrod and doesn't have a cam chain. IIRC the water pump on these shits fairly regularly and can cause the bottom end to wash out the bearings if left unchecked. Also the motor had to come apart to do the water pump. I could be wrong on this though.
 

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dohc cb750s can make for wicked cafe style bikes. though i think the sohc ones make a better sound at full tune. remember, these were superbikes in the day. its not going to look like a t120, but it has a style all its own. like geet said, look for an f. those c models are ugly meh.

jc
 

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quote:Originally posted by Geeto67

it is also pushrod and doesn't have a cam chain. IIRC the water pump on these shits fairly regularly and can cause the bottom end to wash out the bearings if left unchecked. Also the motor had to come apart to do the water pump. I could be wrong on this though.
The sad thing is that the CX actually does have a cam chain that had a problematic tensioner for the first couple of years. It required pulling the motor and taking the back cover off to get at the chain and tensioner. There was a factory recall and I believe after it was done, the mechanic was supposed to put three punch marks after the engine number in a triangle pattern to show the work had been done. Some of them do have a problem with the cam and lifters going out. I never figured out why some go and some don't. They also have a tendency to leak coolant from the metal pipe that goes to the radiator and sometimes the mechanical seal in the water pump would go out. Really not a lot of issues for a 30 year old bike.

Ken

P.S. they are ugly
 

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yup

but even after getting better used carbs, a fork swap, an NOS tank, new tires, and about a dozen small things, i am still <750 in on mine and it now always starts and i havent had to push in awhile :)
 
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