1982 CB750C transformation

[sage]

Bought a 1982 CB750C last summer. Rode it for a bit. One of the mufflers was thrashed, so I installed a 4-1 header and a new can. I love a good Cafe bike, so I decided that I was going to spend the winter collecting parts and building the bike. Well, I collected some parts, anyway... And, to be fair, we did tear the bike apart in November.


So today, Josh (drummer and metal worker extraordinaire) and I (totally useless shop decoration) got to work on the bike. It started off looking like a bike. We figured that the positioning of the old passenger pegs was a pretty decent location for the rearsets, so we popped them on there. Hacked away at the OEM levers, and built the linkages. I bought the rearsets and linkage kit from TC Bros Choppers here: http://www.tcbroschoppers.com/store/index.php?main_page=product_info&cPath=9&products_id=14 - shipping was super fast, I think I got them like 8 months ago. LOL.


After that, we kinda arsed about, took off the Mickey Mouse ear front signal lights, tested the integrated tail light mostly just to see the light show, listened to some Deftones, checked that the pod filter fit the carb, ordered 3 more pod filters, and shot the breeze.


Of my great list of stuff that's gotta happen to this bike over the next two weeks, we didn't get much done, but it was fun and we'll be more diligent workers on Tuesday when we go at 'er again.


List of stuff to do:
re-build and sync carbs
build seat and cowling
sew seat
drop and re-seat exhaust (I bollocksed up the install, I think I missed one of the old exhaust seals, so it kinda pops a bit - might as well fix it)
re wire bike
build battery box and electrical housing deal
install new chain
install clubman bars (I'm thinkin' Omar's 4-ways, anyone wanna chime in on that?)
install braided stainless brake lines (I know there's a rad tutorial on here for making your own lines, can't find it through the search, though)
paint tank, seat cowling, and outer bars of linkage kit with some obnoxious silver flake - maybe black for the linkages


Should only take a coupla hours, right?

 

[YogiBear]

I'm looking forward to seeing progress of your build. If you do decide to go with clubman bars, remember that not all standard clubmans will fit. The triple tree is too wide on these DOHC's. There are still clubmans out there that will fit though.

 

[biker_reject]

Rock on, my brutha!

 

[tweakin]

Should be a great project.

 

[eric2281]

It makes me really excited to see all these DOHC cb750's popping up. I look forward to sharing build ideas with the fellow DOHCtors. Still waiting for a cafe bumpseat revelation though...

 

[sage]

Update:


I cleaned the carbs on Wednesday night, put in new gaskets and o-rings, and changed the jets to accommodate the filter pods and new exhaust. Everything was going well until Josh reckoned that polishing the slide covers would look rad. He was right. He did 3 of them. I decided I wanted to try my hand at buffing, so I did the 4th. Caught an edge, sent the slide rocketing into the wall (nice dent in the wall) and crashing to the concrete floor (nice dent in the slide). Now the slide doesn't fit, so a new one is on the way from Mississippi. $29 lesson learned. That was a fun night.


Thursday night, I dropped the exhaust to check what the problem was there. I had an exhaust leak after installing the 4-1 header. I thought maybe I had left one of the old copper gaskets in there and there was a leak between it and the new gaskets. I bought all new gaskets again, because you aren't supposed to re-use them. It turns out that I under tightened the nuts. The gaskets weren't even mis-shapen, never mind crushed into place and forming a seal. Funny thing is that I tried not to over tighten them. I'm a bit of a monster (6'4", 300 lbs) and I have a tendency to overdo things. Now they're on there good and tight. LOL.


I tried wiring up the LED lights, but something was fucky with them. Nothing was working the way I thought it would, so I put that to rest for another day and just cleaned the frame and engine up. 28 years of road snot added on to 8 months of living in Josh's shop made for a good hour and a half cleaning job. Used WD-40 and the pink shop towels. It smells like a gun now. Unfortunately, this is probably as clean as the bike is ever going to be for another 28 years.


Tomorrow morning: figure out the lighting, install handlebars (old adjustable Torozzis, I measured them, I hope they fit), and mockup the seatpan/cowling arrangement out of bristol board. I might even transfer that design onto the metal and try my hand at cutting. We'll see what's up with that.

 

[sage]

Saturday morning bike build notes:


Managed to get the bars mounted. Throttle side stuff came off ok, no real problems there. Clutch side stuff, well, I think the previous owner glued the grip on. So I used the circular wrench (angle grinder with cutting wheel) to remove the stuff from the other side. I was pretty impressed with myself on that one. First time ever using an angle grinder. The bars are not Tarozzis, they are Tommasellis. They look pretty slick on the bike. The margin is really tight. I want to adjust the bars outward a bit as there is a little bit of tank interference, but I broke the 10mm hex wrench trying to loosen them. Oops.


I was arsing about with the wiring until I realized that nothing was going to work right with a flat battery. It was putting out just over 9V. So I'm gonna hook it up to my trickle charger tonight and sort the rest of that out tomorrow. I bought an electronic relay, so hopefully I won't have any flasher issues. I have some of those resistors, but if I can streamline this stuff, I'm gonna do it.


I mocked up the seat with bristol board. Looks pretty tight. Forgot to take pics. It'll probably be a seat soon, so that'll be exciting.


Looks like I'm going to have to rebuild the forks. There's some juice coming out of the left one. Balls. The parts aren't available until mid July.

 

[YogiBear]

I had a problem with my drag bars clearing the tank on my CB750C. I added a bit to my steering stops on the triple tree. That's on option if you run into clearance problems.

 

[sage]

Got the trickle charger hooked up, checked the lights, they work fine now with the right power. Anyone have any tips for getting the flasher relay out of the fuse box? That thing is in there good and I'd rather use finesse than brute force if at all possible.

 

[sage]

j'suis un idiot... that was the starter solenoid... good think I didn't damage it... where the balls is the flasher relay?

 

[eric2281]

If your '82 750c is anything like my K, which I'm fairly certain it is, it will be behind the left side cover & looks like this~

 

[sage]

Alright, replaced the flasher relay, still no love. Gotta find one that is not mechanical.

Got the oil drained, ripped off the brakes (SS brake lines arrived, so preparing for that), and ripped off the seat stuff. We're going to re-use the seat pan, so it's getting walnut blasted this afternoon.

Carb slide arrived, filter pods arrived, fork rebuild stuff arrived early, so this thing should be on the road in no time now. As long as everything goes smoothly, that is.

 

[biker_reject]

Update:


I cleaned the carbs on Wednesday night, put in new gaskets and o-rings, and changed the jets to accommodate the filter pods and new exhaust. Everything was going well until Josh reckoned that polishing the slide covers would look rad. He was right. He did 3 of them. I decided I wanted to try my hand at buffing, so I did the 4th. Caught an edge, sent the slide rocketing into the wall (nice dent in the wall) and crashing to the concrete floor (nice dent in the slide). Now the slide doesn't fit, so a new one is on the way from Mississippi. $29 lesson learned. That was a fun night.

Aha ha! I did the same damn thing... with two of them! Luckily, I found a really crusty set of carb slides on flea bay! Yep, live and learn. I don't even remember how many weekends it took me to clean up my engine and polish the covers. Quite a few. Never done so much polishing in my life! :-D

 

[Andreas]

How is that rear set position working for you? I was thinking of the same thing on my 82 custom but was afraid it might be too far back. Nice ride.

Bought a 1982 CB750C last summer. Rode it for a bit. One of the mufflers was thrashed, so I installed a 4-1 header and a new can. I love a good Cafe bike, so I decided that I was going to spend the winter collecting parts and building the bike. Well, I collected some parts, anyway... And, to be fair, we did tear the bike apart in November.


So today, Josh (drummer and metal worker extraordinaire) and I (totally useless shop decoration) got to work on the bike. It started off looking like a bike. We figured that the positioning of the old passenger pegs was a pretty decent location for the rearsets, so we popped them on there. Hacked away at the OEM levers, and built the linkages. I bought the rearsets and linkage kit from TC Bros Choppers here: http://www.tcbroschoppers.com/store/index.php?main_page=product_info&cPath=9&products_id=14 - shipping was super fast, I think I got them like 8 months ago. LOL.


After that, we kinda arsed about, took off the Mickey Mouse ear front signal lights, tested the integrated tail light mostly just to see the light show, listened to some Deftones, checked that the pod filter fit the carb, ordered 3 more pod filters, and shot the breeze.


Of my great list of stuff that's gotta happen to this bike over the next two weeks, we didn't get much done, but it was fun and we'll be more diligent workers on Tuesday when we go at 'er again.


List of stuff to do:
re-build and sync carbs
build seat and cowling
sew seat
drop and re-seat exhaust (I bollocksed up the install, I think I missed one of the old exhaust seals, so it kinda pops a bit - might as well fix it)
re wire bike
build battery box and electrical housing deal
install new chain
install clubman bars (I'm thinkin' Omar's 4-ways, anyone wanna chime in on that?)
install braided stainless brake lines (I know there's a rad tutorial on here for making your own lines, can't find it through the search, though)
paint tank, seat cowling, and outer bars of linkage kit with some obnoxious silver flake - maybe black for the linkages


Should only take a coupla hours, right?