piston to valve clearance

bfd402 · Post by **bfd402** » Fri Jan 29, 2010 1:02 pm

Hello
I am swapping out cylinder heads on my CB77 vintage racebike and am considering replacing the stock cam in it with a period race cam I have. With the stock cam I have a ton of piston-valve clearance (actual number not in front of me but perhap .070-.090) and with quality valve springs there have been no issues. Anyone have a minimum number they use or feel comfortable with in a high rpm situation like this?
thanks
bfd

jerry · Post by **jerry** » Fri Jan 29, 2010 2:10 pm

Dear bfd, I run .038 inch inlet and .045 inch exhaust. No problems. However you must remember that the entire valve train must be under control at all times. Best regards Jerry

bfd402 · Post by **bfd402** » Fri Jan 29, 2010 2:25 pm

Thanks Jerry, that's exactly what I was looking for.
bfd

jerry · Post by **jerry** » Fri Jan 29, 2010 3:22 pm

Dear bfd, By the way if you Google mcnews.com.au then click on to Late Braking News and then go to Jan 29 Multimedia Classic 500 Race with Levi Day and Download you will see a 500cc CB/72 Superhawk go about its business. Enjoy. Best regards Jerry

bfd402 · Post by **bfd402** » Fri Jan 29, 2010 3:45 pm

Great Link!!
As hot as that bike is it still sounds like a 305.
You might need to include a camera facing backward to keep it interesting!!

Thanks for that Jerry

davomoto · Post by **davomoto** » Fri Jan 29, 2010 7:38 pm

Hey guys, it looks like Levi brought a gun to a knife fight! His bike was so much faster than the others, it looked like they had the anchor out.

davomoto

jerry · Post by **jerry** » Sun Jan 31, 2010 3:14 pm

Thanks for the compliment Davomoto. The bike was doing 150 plus down the straight. Jerry