Topic: A young Austrian resurecting a former 1000cc drag bike

[Austrian_CB]

Hello all,

My name is Simon, I'm 25 and from Austria. Have been living in Southern Virginia for a few years now due to work (restore Mercedes and Porsche automobiles for a living)

I built a 1979 CB750 DOHC café racer last year. 2 months later someone offered me good money and I let it go. I still regret it!

But also last year I purchased a 1972 CB750 aka a pile of parts and an engine that was disassembled for next to nothing. The bike was a former drag bike (not pro I think) that the guy who disassembled it bought in 07 from the original builder in Florida.
Didn't know anything really about early CB750s then but I thought it was a cool project that I wanted to tackle. And I like history and it had a wheelie bar on it so it had to be fast   

Long story short I had the whole project sitting in the corner of my shop for a year and a few weeks ago I finally started the process.
As of right the bike is completely stripped down to bare frame but I stopped there because I ran into some titling issues (VIN on bike doesn't match title, my fault not to check when I bought it)

Then I started focusing on the engine, because that's the part what makes this bike special but it turned out to be a odd (not necessarily good) configuration of parts.
While tearing it down and documenting everything if found following things. 70.5mm Venolia "262" pistons, sleeved cylinder, RC 327 cam, bigger valves, titanium retainer, racing springs, ported and polished head, upgraded clutch, upgraded ignition etc.
... I have no idea how the thing held up over the years on stock rods, chains and studs (reason for tear-down was leaking base gasket ive been told)

Anyways, everything seems to be in good shape. No abnormal wear. Cam looks like new.

My work so far includes teardown/cleaning parts, soda blasting case/cylinder/head/valve cover etc and painting semi-gloss black. Plasti gaging and making measurements of cylinders and pistons, crank etc., lapping in valves.

I already have a bunch of upgrades so far. Cycle X super rods, Cycle X hd primary and cam chains, new Wiseco piston pins, APE hd studs all new OEM cranks and conn. rod bearings to spec, gaskets/seals etc.

Now where at the point for the reason that brought me onto this Forum. I'll need some advice from CB750 professionals to make this engine "streetable" and "reliable" on pump gas.


I appreciate anyones help, ideas, suggestions and information to get me through this build to make it run and look good! 

Right now I'm trying to figure out what thickness/material base gasket (3" od sleeves) and head gasket to use (had approx. 0.156" thick copper gasket installed) .. any suggestions?

Also, should I re-use pistons? Does thermal barrier coating make sense? Member "gschuld" pointed me in some good direction for coating and gave me good information!  thanks George 


Bike is going to be a streetable café or brat bike when its done! So I wanna make the engine hold up.
But guys please keep in mind I'm 25 and can't break the bank for this build so I can't go full on Nascar on it haha


Cheers,
Simon

[calj737]

For specialty performance  Thermal Tech in Hopewell, VA. Andy Vaughan does a great job, is fairly priced, and focuses on performance motors and exhausts.

I’m up the road from you in Richmond.

[MD]

Welcome from MN,

Interesting story so far.  Start a build thread in project shop and copy much of what you have already stated.  And keep the pictures coming, they are appreciated.

-MD

[754]

Nice start on a cool bike. Welcome aboard.
 Your spare engine cases, rear mount by chain is broken off.
 The rusty pulley in black crate, is a Harley front beltdrive pully.
 If the lens on the taillight says Sparta, its a real one....many many fakes out there.

[gschuld]

Welcome

Should be a fun project.  This is a good forum for sourcing both info and parts.  Some of us tend to hoard the more rare and/or unusual parts, but don’t necessarily advertise the fact.  When you need things, could be best to ask if someone has what you need.  You might get surprised with under he radar PMs with exactly what you need.

I’m glad to see skilled members of the younger generation showing interest in these old dinosaurs.  They can be surprisingly powerful if built right.

George