Topic: Running a 1000 cc RC kit with stock carbs and unidentified Yosh cam

[Turbogrimace]

I have a yosh cam that I think is a stage 1 or 2 and I was thinking of running a 1000 kit with it using stock carbs and an ARD magneto.  Has anyone had any experience with a similar setup?  What are the jetting requirements for stock carbs on a larger engine like this?  Any idea of how I could ID my Yosh cam?  Where to measure?

Im looking for some general advice for this setup if anyone has ever dealt with something similar.  And its a CB750F bottom end.

[scondon]

I think that cam duration/lift, intake/exhaust valve diam., and airflow(porting/stock) through the head will play a roll in how you want to jet your carbs. If it's just a 1000cc bore, and no other changes to a stock bike, then the jetting doesn't change very much( I think?). Cam, exhaust, porting/valve, ignition will come into play, so best to know as much as possible about what you have before guessing at starting carb settings.

Axl has some really excellent info regarding old Honda race parts. Here's his page on Yosh cams:

http://www.satanicmechanic.org/yoshicam.shtml

[Jerry Rxman Griffin aka MuthaF'er]

Turbo,

I'm running the Yosh Daytona Stage II in my 75 750F with 812 Yosh kit and stock head except stainless intakes and springs. EXCELLENT top end even without big valves and porting. I'm looking forward to Mike's stage III head and the 900 kit to be installed soon then see what it's like. Mid range would probably be better with their Road Special cam. I think that 1000 kit will help with the mid range though. While Axle is definitely an authority on 750's I do need to disagree on the Daytona cam specs he has listed. I still have my spec sheet they provided with my cam. The open/close/duration he lists are identical to my spec sheet. The intake max lift provided to me by Yosh is 9.72mm which is .382 inches BUT the exhaust lift is 8.60mm which is .338 inches. Perhaps a change in the cam or differences in individual cam specs?

I don't think it's practical to actually take measurements directly off the cam. I think you'd need to take measurements of valve lift/openings while it is installed in the head. I can provide the spec sheets and installation instructions if you need them. 

Jerry

[Turbogrimace]

Thanks a lot for the information!  Ill take any literature you would like to provide. PM me and Ill give you my email address.

I was thinking that I could measure the lift on intake and exhaust and compare it to Yosh's cam specs on Axles site or somewhere else.  None of the cam's lifts are exactly the same and it would at least give me an idea of which cam it is. Now this would only work if they are advertising lobe lift.  But I could calculate the lobe lift from the total lift if I new the rocker arm ratio.  Anybody know this?