Topic: Camshaft question/valve lash

[Mitchell]

Hello all im new here and have a question. I have a 75 cb750f I picked up out the junk yard and the camshaft in it apears to be stock with but its stamped rc240 on the end. The vavle springs and retainers appear to be changed out at some point, the retainers are red. Now my question is what should I set the valve lash to? I have set them to stock specs and they sound loud and lose. any info on this would be appreciated.

If I remember correctly I read some where that someone back in the day made a kit called 30/30 kit. It was a 836 with a regrind cam that was marked rc240 with 30% more power and 30% percent better fuel economy, but I dont know it was a long time ago when I read that so im just fishing for info here. but really all I need to know is what to set the valve lash to.

Thanks

[Mitchell]

Thanks man!

[Bill/BentON Racing]

RC 240 cam lash is in. & ex. .004 inches,Bill

[Mitchell]

Thanks Bill. Mr. bill dont you have a turbo 750? What cam are you running in it?

[Sam Green Racing]

It's a mild one Mitchell that's all he was told. Bill has never had the top cover off that I know of.

Full story here mate.  http://forums.sohc4.net/index.php?topic=115091.0

Sam.

[Bill/BentON Racing]

Sam,you rt,but paint work supposed to be ready by weekend or first next week.May pull cover soon,Bill

[Mitchell]

I am getting the 75f road worthy so I can ride while I paint my 76k with a blow thru set up on it. Its got a stock cam in it and while I had it out I was going to put a 750A cam in it.

[Sam Green Racing]

That might not be a bad idea.

[scottly]

There was a cam commonly known as a 30-30. It was a factory Chevy Hi-Po cam used in the original 302 Z-28 motors; arguably the most radical small-block cam Chevy produced. It was nick-named 30-30 because the hot valve lash was set at .030" for both intake and exhaust. BTW, 30% more power and 30% better fuel economy are an oxymoron, at least with regard to a camshaft.  

[Mitchell]

I can' t remember where I read it or really what I read but it was a kit with pistons, cam and all the necessary parts.

Thanks for the replies guys!

[754]

It was the RC catalog.. 30 % more power, 30% better mileage..

[NitroHunter]

I had that RC 30-30 kit with 240 cam and RC pipe. With a valve job, milled head, and zero deck, it would just flat run away from a stock CB, and give Z-1s more than they could handle. And on several long trips it got 50+ mpg. It was a very good combination for the price.

[Mitchell]

What all came in the kit?

[754]

I think it was cast 836 pistons,cam, and pipe...

[NitroHunter]

Yep Frank strait out of the RC dream-come-true catalog. Back then it was a lot of dough for an employee of Uncle Sam but it was SO worth having the baddest hot rod of the ship. 

[Mitchell]

Thanks guys. I got it all put together and valves adjusted and it runs great! I'm guessing it dont have the 30/30 kit cause it had the stock exhaust on it when I picked it up.

[NitroHunter]

Very cool Mitchell, the sky's the limit for future upgrades, but for now go enjoy your ride.