[puff336]

My 7 year old got a new CRF50 last Christmas. Started racing in July. Started making mods to improve his performance....finished 7th, 5th, 4th, 3rd. Here is what we did up to the 3rd place finish (white bros. exhaust, K&N Filter, dropped front sprocket 1 tooth.) Since last race (July), we replaced the rev box, took a stock main jet and drilled it out 4/100mm, and advanced the timing. The bike seems slower and with the new jet we couldnt seem to get the fuel/air mix right. I took it to a local mechanic and he cannot seem to do anything either. In fact he told me yesterday on the phone he put the stock jet back in and the bike seems slower than a stock bike he has at his shop. Any ideas will be appreciated. We race again Sat. night and Im thinking of sticking with the stock jet, putting the stock rev box back and going back to stock timing. Should anything we've done have reduced performance?

Thanks for any help.

[crfsonly]

if you can't figure out what is going on by sat. morning i would definitely be prepared to go back to the previous set up. prior to that i would go back to this set up and try one thing at a time to determine where the issue is. start with the rev box, then timing, and lastly jetting. my guess is the problem is in the jetting. if the jetting was ok before with the previous mods (k&n air filter and wb exhaust) then you might not need the jetting adjusted.

ken

[ncj01]

Here is what we did up to the 3rd place finish (white bros. exhaust, K&N Filter, dropped front sprocket 1 tooth.)

The bike seems slower

Should anything we've done have reduced performance?

I'm no mechanic so take this with a grain of salt...

But....dropping the front sprocket by 1 will definately make the bike slower...if you want the bike to go faster, up the front sprocket by 1...

The smaller front will make it pull harder down low, but you'll rev out faster, with less top end.