80 DOHC CB750 - Tale of two budgets

Hey guys, been lurking here for a while, just started posting yesterday... checked out quite a few other cafe/CB forums before setteling on DDT... this place has been really helpfull with narrowing down my vision for what I want my bike to be and what parts/fab work will make that possible... so thanks for all the inspiration... time to return the favor and help myself stay on task along the way.

A little backround - I was in the market for a CB because of a recent job change that brought me within 10 miles of home, perfect commute for a bike (almost all back roads)... I happend to mention to a co-worker (sits right next to me) that I was heading to a swap meet to look for a bike and he says, "oah yea, I have a CB750 sitting in my garage, you can have it"... Two days later it was in my truck driving home... I ended up making him take $50 for the bike.

The PO wanted some carb tuning done 4-5 years ago and had a local shop tell him he should just buy new carbs because of what they would charge to rebuild, tune, and sync... Discouraged, he parked it in his garage and it hadnt moved since. He even thought about just bringing it to the scrap yard. So im kind of saving the bike.

Its a DOHC C model, by no means an ideal cafe starter bike but it will do just fine for my needs... at least I wont have any guilt in cutting her up... I attempted to start it up, but it just spewed fuel all over my garage from the overflows... pulled the carbs and found most of the jets clogged solid. I havent done a great job of documenting what I have done so far, but I will try and piece some pics together.

I call it tale of two budgets because I am trying to keep the costs as low as I can without sacraficing on function or style... which means lots of hours logged on ebay and dragging my wife and kids to swap meets.

The day I brought it home,

Decided to keep the crappy stock carbs for this year... maybe CR's and a big bore kit next year, but for this round factory will do... So I pulled the carbs for dissasembly and cleaning... ordered Randakk's rebuild kit and all new stainelss hardware from bolt depot.

Nothing special here, just dissasembled carbs... should have them back together soon.

I basically plan on getting this bike in mock up form and driving it that way for the summer... then break it down again next winter to do all the finish work... so no harm in pulling the motor now to make it easier to handle around the garage.

This is how its sitting now... and this is the low budget part... $75 for the GL1000 trees and forks, $10 for the GL wheel (I only plan on using the hoop), $5 for the clip ons... Im prety proud of myself, but my wife thinks im an idiot. lol

My plan was to go with a 19" rear wheel... but damn 19" rear tire choices SUCK... so when I found this super rare 18x2.5" GB500 rear wheel I couldnt belive my luck... it is is really nice shape too... only one scar and it will sand/buff out... got it complete w/brake and cush drive hubs, sprocket and axle w/adjusters for $200... not a "steal" but prety reasonable IMO.

Dissasembled ther GB500 rear to clean / polish everything... ordered new wheel bearings to accomodate the CB750 rear axle... the GB axle is only 17mm and isnt long enough to mount onto the 750 swing arm... I will have to open up the hole on the brake plate to fit as well.

Spokes polished up nice, not perfect, but not worth buying new ones either... 20 down, 20 to go.

Welcome LaynDoor!
I can not believe the DOHC 750's that are coming out of the woodwork lately! I too have a lowly "C" model that is getting revamped.
Clip-ons for $5! You are a bargan shopper, congrats! That rear wheel looks really sweet, should tie together with the fron GL wheel nicely....
Looking forward to more updates as they occur!

With my wheel size finaly decided, I was able to get the tires... Bridgestone battlax 100/90-19 for the front and 120/80-18 for the rear... cant wait to get this thing rolling on spokes

And heres the high buck side of the budget, the parts ive gathered so far and what I still have to buy... Since I will be using this bike to get back and forth to work durring the summer it needs to be reliable... so all new electronincs, bearings, controlls, and probably a Cycle X charging system (although I did manage to get the Dyna ignition for $100 less than retail!)

Once I get it in rolling form I will be calling race tech for front springs and emulators... not to mention the nearly $1K wish list I have started over at Dime City (14.25" progressive rear shocks, billet top clamp, digi spedo/tach, stainless shorty mufflers)... damn that stuff adds up quick.

Hoosier Daddy said:

Welcome LaynDoor!
I can not believe the DOHC 750's that are coming out of the woodwork lately! I too have a lowly "C" model that is getting revamped.
Clip-ons for $5! You are a bargan shopper, congrats! That rear wheel looks really sweet, should tie together with the fron GL wheel nicely....
Looking forward to more updates as they occur!

Click to expand...

Thanks HD! Ive been following your build on a few forums... yea, when I started reading up on this bike, i realized the DOHC was kind of the red headed step child of the cafe scene... and the C model, I was afraid to say I owned one!... With all the build threads lately you would think its more of a contender, or at least not an outcast.

The guy wanted $10 for the clip ons but i talked him down to $5 lol... one of the bars is bent but I can have aluminum ones made for almost nothing... and they were for 38mm fork tubes but I had the slot milled about 1/16" larger so they would clamp down on the 37mm GL's... it was a pretty nice score.

DOHC fan signing on for your build. Welcome to DTT.

Good tire choices. Nice bucket of parts, but that's a heck of an investment in a bike that hasn't run for a while. I'd have made running the focus for now - but it's done so no point in crying over spilled milk, as they say. Get it running first and the pretty stuff and paint can wait for next year.

Dyna coils or DYNA S ignition? Doesn't that bike come with electronic ignition from Honda or was that for coils?

Solid start, great to see another DOHC builder out there. I'm rebuilding an 81 CB750K and I like what you did with the rear wheel swap. Did you polish all the spokes at home? Interested in the tools/chemicals needed to unlace, polish, reassemble the wheel. Please post pics of that scary carb rebuild as well Good luck!

Teazer - that was the plan... I ordered the battery and ignition right when I got the bike expecting to install them and get the bike running... when the carbs spewed fuel I started stripping it down and one thing led to another and im all like "how did I get here" lol... kidding aside though the oil was perfect, it turned over nicely and showed some very small signs of life... famous last words - im confident that cleaning the carbs and a valve adjustment will be all she needs to run again.

thats a Dyna2000 ingnition system with coils and wires... didnt "need" it, but I would have had to replace the stock ignition anyways... it was a splurge for sure but I got a great deal on it... besides all the goodies it has, Im expecting the dyna unit to be much more reliable than the stock system that spewed black goo all over the place.

Paint and powder will wait for next year... Im "finishing" the wheels because I dont want to have to mount/dismount tires over and over again to get the wheels polished the way I want them.

As for the investment, I had budgeted $500-$800 for the bike itself... so since I got the bike for $50 im telling myself that the bucket of parts was basically free... thats what I tell my wife anyways.

Trust me, I cant wait to hear this thing run again!

kraptastic k said:

Solid start, great to see another DOHC builder out there. I'm rebuilding an 81 CB750K and I like what you did with the rear wheel swap. Did you polish all the spokes at home? Interested in the tools/chemicals needed to unlace, polish, reassemble the wheel. Please post pics of that scary carb rebuild as well Good luck!

Click to expand...

Yea, polishing them at my dining room table... putting the spokes in a cordless drill spinning slowly with a microfiber cloth and Heavy Metal Polish Red formula to get the heavy stuff and then finish with Mothers Billet polish... Nothing needed to unlace besides a wrench and screwdriver.

As for the investment, I had budgeted $500-$800 for the bike itself... so since
I got the bike for $50 im telling myself that the bucket of parts was basically
free... thats what I tell my wife anyways.

Click to expand...

And that's how it starts... ;D

Hoosier Daddy said:

And that's how it starts... ;D

Click to expand...

It may be flawed logic, but its MY flawed logic! ;D

Kind of a lame update... but I was bored this week/tonight so I got some work done on the rear hub...

Stripped the outer flanges and brake plate with this no fume/citrus/biodegradeable stripper... It actually worked reasonably well... and it smelt so good that my wife let me do it in the kitchen sink! ;D

Aaaaaaannnd... sanded the brake plate... should have sanded more... but I'll remember that when I do the hubs

Used the Eastwood deluxe polishing kit with a harbor freight electric die grinder and a variable speed controller... im prety happy with the result... certainly driver quality.

That GB500 brake unit has some nice lines to it. Good job on the polishing too. 8)
I have ofeten thought about picking up an electric die grinder, my pneumatic one is an air hog and even though I have a decent sized compressor it can't keep up... Find myself having to wait for the PSI to build back up so each job takes longer than it should.
Plus with a electric one I could use it in the house where it is nice and cozy.
Hows the carbs comin?