1982 CB750F Super Sport - (no longer a Brat Project)

armourbl

Active Member
Update
For anyone coming across this for the first time, I've pretty much decided to not do a brat project with this bike. I'm going to just freshen it up, and keep it pretty much original. I will personalize it where I see fit, but won't do anything dramatic or anything that couldn't easily be reversed back to stock.

Original Post
I'm going to use this thread to try and document my Brat build using a 1982 CB750F Super Sport. Progress may be slow, and it will likely not begin to take true Brat form until after I've had a chance to thoroughly go through the bike and make sure it is worth the continued investment.

I've wanted to do a build like this for quite some time, but only recently became more motivated to go for it. I just picked up my starter bike, which turns out to be in a lot better condition than I expected to find, and also cost more than I wanted to initially invest. But, it will give me a better starting point and may result in a better final result. The original seller was asking $4,000 for it. I offered $2500 given the original condition and he later accepted as you can see. Attached is a pic of the bike.

You can see all of the photos I've taken, and will take on my Google Drive. Here is the link. https://drive.google.com/drive/folders/0B2DCeFVNPpHNTEtpMUJDYjRkcTg

There are a number of things going for it as far as I see it:
-- Condition of the bike overall is very good, only slight mods and improvements, appears to have been maintained very well
-- Engine is already black, which is the final look I want, but I may still have to paint it to freshen it up
-- Dual discs up front, disc in the rear, all dual pot calipers
-- Should be able to reuse a lot of parts on the bike to keep costs down
-- Came with box of spare parts, some of which will help keep costs down
-- Tank and its paint are in very good condition, no rust inside, only minor blemishes on the paint that are only noticeable close up
-- Bike was very recently serviced by a professional, carbs gone through, valves checked and set to spec, etc.

I've already discovered some issues with the bike that will need to be resolved:
-- Rear brake disc is grooved badly and will likely need to be replaced, needs new rear pads as a result
-- Charging system issue, I believe the alternator rotor is bad as I don't get any resistance across the slider rings
-- Rear shocks are toast and will need to be replaced
-- Air box boots are not lining up with the carb correctly and therefore not sealing right, may be a minor fix
-- Clutch is slipping, most noticeable right at 95 mph in top gear. RPM's increase, but power to the wheel drops to nothing

Here are pics of my inspiration builds. I won't be doing clip-ons, but otherwise, I really like the first pic a lot. I'd probably do a bit thicker seat as well. I'm still forming my final vision for the bike.

IMG_3555.jpg


Tim-Brown-CB750-3-700x496.jpg


ben
 

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Re: 1982 CB750F Super Sport - Brat Project

I have this week off so I've been slowly going through the bike as much as I can. First order of business was to give it a bath. I hit the engine with some degreaser, then gave it a basic wash -- definitely not a detail job.

After that, I did some basic paint restore on the tank and other body work.

Anyone know a better way to get the engine super clean and looking as good as possible without needing to repaint it?



ben
 

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Re: 1982 CB750F Super Sport - Brat Project

Welcome to group

no offence to you and what you want to do but I would rather have that 750 just the way it is......that bike is in great shape
 
Re: 1982 CB750F Super Sport - Brat Project

Removed the rear shocks and dismantled them with the intention of cleaning up the spot rust. Discovered that the shocks are toast. Almost no dampening in them at all. The shaft can be depressed too easily, and in some places along the travel there is no resistance at all. Looks like I'll be replacing these.

I've already sent an email to Chris at the linked website for his recommendations, but I'm open to other suggestions as well.
http://chrislivengood.net/wp/product-category/shocks-3/

Too bad really, because the stock shocks were cleaning up nicely.

ben
 

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Re: 1982 CB750F Super Sport - Brat Project

Clean motor??
Elbow grease will do it
 
Re: 1982 CB750F Super Sport - Brat Project

Kamn said:
Welcome to group

no offence to you and what you want to do but I would rather have that 750 just the way it is......that bike is in great shape

I totally get it, believe me. Already got my first compliment at a gas station from a guy who walked up just to tell me how clean it was and how much he misses the one he had. Then he pushed me to bump start it since the battery decided to die at that very moment. LOL.

The ideal of taking one in such good condition and tearing it down was and is a point of concern in my head. I think the only thing that would be a permanent change would be the need to cut the rear subframe in order to weld on a hoop. This will be one of the last things I do to the bike, right before any final paint work. But, believe me when I say that the bike isn't quite as perfect as it may appear in the photos.

One idea I'm playing with in my head is to keep all of the original parts and be able to put it back to stock. That would mean I'd need another gas tank and frame, but I may be able to find those for cheap. We have a very good motorcycle salvage yard in my area.

ben
 
Re: 1982 CB750F Super Sport - Brat Project

These posts are happening quickly because I'm catching up on things I want to document.

Too much time on my hands, idle time in the garage, keeps me nit picking away on the bike little by little. Decided to remove the passenger foot pegs since they were flopping around and I don't need them -- my wife rides her own motorcycle. Then took out and old Never Dull can and started working over the bare aluminum parts. Could only clean up the rear set brackets a little with them mounted to the bike, but it was an improvement.

I don't really like how gody these things are, but I don't know of any alternatives either. I may end up having them powdercoated black to make them disappear more, blend in. I do like that they appear to be the European units, that put the foot pegs back further for a more aggressive position.

ben
 

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Re: 1982 CB750F Super Sport - Brat Project

No pics of the work I did on the brakes. They were squealing like a stuck pig. It was horrible. So bad that I wanted to just not use the brakes. I read up on everyone saying this is common, and hard to resolve.

My currently solution seems to be working. Removed the calipers, pads, pins, floating bracket, etc. Cleaned it all up. Cleaned, sanded, and cleaned the rotors. Then applied some caliper grease to all of the mating metal surfaces such as the pins, back of the pads, etc. When I reassembled everything I make sure the calipers were able to float freely with no binding.

The couple of test rides I've done have revealed that it is working so far. Only a slight hint of squeal every now and then.

ben
 
Re: 1982 CB750F Super Sport - Brat Project

More progress on the bike today.

Got the new Clutch Safety Switch wire made and successfully installed. The bike was missing the wire, and therefore would only start in neutral. Tied into the green/red, and green wires behind the headlights.

Fixed the charging system issue. Turns out one of the brushes had a bad wire. Luckily I had a spare stator in the box of spares that came with the bike to rob parts from. Discovered the bad brush when taking the existing stator out of the cover. Battery now gets almost 14 volts when RPMs are up. Cleaned up the rotor while everything was apart.

Got the air box boots to finally line up and clamp down properly to the carbs. What a pain in the butt that is, took several hours of messing with it. Also found the carb float bowl drain hoses were not attached, and connected them.

Found valve cover bolts were not tight. Could be why oil was seeping from it. Haven't had a chance to ride the bike yet to test if this solved the problem.

Went over all of the plastic parts with some Meguiars Ultimate Black. Made a minor improvement in the condition.

ben
 
Re: 1982 CB750F Super Sport - Brat Project

Took the valve cover off today to try and figure out why it was leaking from the right front during rides. Quickly discovered that the culprit was the exhaust cam clamp bolts were loose in this location.

You can clearly see the gap between the clamp and the head. This would in affect prevent the valve cover in this location from mating with the head properly because the bolt would bottom out prematurely on the cam clamp.

Hopefully it won't leak anymore now.

ben
 

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Re: 1982 CB750F Super Sport - Brat Project

While I had the valve cover off, decided to check the valves. Glad I did. All of the intakes are on the loose side, with cylinder number 4 being the worst of the bunch. Exhaust side were on the tight side at mostly .004.

See attached pic for my noted measurements.

Waiting on a Motion Pro bucket depressor to arrive so I can remove the shims and hopefully get everything back into spec (.005). Would you even bother with the exhaust side since they are so close?

ben
 

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Re: 1982 CB750F Super Sport - Brat Project

Cleaned up the valve cover and painted it.

Primed with VHT SP148, then covered it with VHT SP139 Satin Black.

I used a halogen work light to help heat and cure the paint. Pics are while paint was still drying.

ben
 

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Re: 1982 CB750F Super Sport - Brat Project

Took an extra seat that came with the bike and took it apart with the intention of seeing if I could modify and reuses the seat pan. The idea is maybe I can get the look I want without having to cut the frame.

I cut the back end off of the seat pan. I'm trying to get the seat top line to match the height of the rear cross member to achieve the lowest profile possible within that constraint. If I use another rear fender and the rear mount points of the frame I might be able to blend everything together.

I'm a tall guy, and don't want to shorten the reach to the foot pegs from the seat anymore than is necessary either. So the plan was all along to have a thicker seat foam than most go with.

Maybe going this route I can make it possible to put the bike back to stock, 100%. Just brainstorming for now.

ben
 

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Re: 1982 CB750F Super Sport - Brat Project

Kamn said:
Welcome to group

no offence to you and what you want to do but I would rather have that 750 just the way it is......that bike is in great shape
Yup. That's a cherry bike, leave it alone.
 
Re: 1982 CB750F Super Sport - Brat Project

Oh no he won't. He's got his hands in the motor for no reason at all and he's gonna eff it up as soon as he gets the proper tools.

Leave the goddamn shims alone dude you are over thinking shit and by the time you're done you'll have a parts bike.
 
Re: 1982 CB750F Super Sport - Brat Project

Really? You think I'll fuck it up? What is so terrible about setting the valve clearance properly?

Ben
 
Re: 1982 CB750F Super Sport - Brat Project

You don't even know what cams you have. Many high performance cams require more clearance.

Valves should be adjusted to the loose end of the spec because they tighten over time. Possibly your cam requires a bit more clearance than stock...how do you know? What you do know is that it was running good before you started 'fixing' It. If it ain't broke and you don't know what a slotted cam sprocket is leave the damn thing alone.

Not a single shim needs messed with anyone saying otherwise is wrong.

Was it ticking wildly? Was it bogging? was it running out of breathe at high rpm? NO. Know how I know? Cuz you said it was running fine.

You're gonna put too thick of shims in and next thing you know you'll be asking why you lost power.

You're messing with stuff just to mess with It. Go for it but don't be surprised by an I told ya so when it runs like poop.
 
Re: 1982 CB750F Super Sport - Brat Project

Hi Armor... You have a pretty cool 750F there. I had one of these for a bit. I would have to agree with others that I wouldn't cut yours up. It's nice and close to original, these were Superbike machines and made to run and handle. It IS your bike but bratting out a nice 750F would be a bummer if chopped up. I would look for a "K" model and hack the shit out of it but that's just me.

Also, IMHO I don't think it's wrong to check valve clearances on used bikes, even if it's running "ok" Stick to the loose side of the measurements though. Don't forget the cam chain tensioner either.
 
Re: 1982 CB750F Super Sport - Brat Project

canyoncarver said:
Hi Armor... You have a pretty cool 750F there. I had one of these for a bit. I would have to agree with others that I wouldn't cut yours up. It's nice and close to original, these were Superbike machines and made to run and handle. It IS your bike but bratting out a nice 750F would be a bummer if chopped up. I would look for a "K" model and hack the shit out of it but that's just me.

Also, IMHO I don't think it's wrong to check valve clearances on used bikes, even if it's running "ok" Stick to the loose side of the measurements though. Don't forget the cam chain tensioner either.

Thanks, I may just do that in the end. For now, I'm just going through the bike and make sure it is mechanically sound, cleaning things up, minor improvements, correcting issues, but not major changes. The original condition is growing on me.

I may have to look for another bike to work on as the brat project. I'm in no hurry for the moment. For now I can enjoy the bike as is, and it is giving plenty of enjoyment just working on it as is.

ben
 
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