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I just acquired a project bike and will probably need to rebuild the top end. My question is : Is there a reason I can't seem to find a over sized piston/ring set for the bike (04 CRF230F). I've looked around and everyone has the standard size (65.5MM)but none except the Big Bore kits that are over sized. It smoked pretty good when I last saw it run and I'm waiting on a carb rebuild kit to get it running now since it has been sitting up for a while. Are the jet numbers on the factory jets also? I have a friend at a bike shop going to dip the carb for me so I don't have it in front of me to check, but I'm curious as to what jets it has and which ones I may need down here in Bayou country (Louisiana).

BTW this is a great site with tons of info! I can't wait to get my bike running.



Bam Bam

BBR makes a Big Bore kit for it . It gives you 10 more CCs. Get a Web 89a cam for a 150f and get new valve springs and keepers. Do not get the BBR HD valve springs there have been some issues with them. The 89A cam is a drop in swap but your OEM springs are probably shot. Get a new timing chain too. Changing the pipe is a matter of opinion when it comes to performance improvement. Louder is not always an indication of increased power. The OEM pipe actually works pretty well...its just heavy. Check out Mike Coes work on 230s. Its very accurate and dyno proven.
OEM jetting is 102 main and 40 pilot. Get a 45 pilot and 120 main, put the clip on the needle in the 4th slot from the top. Open the airbox and get a Twin Air filter.
O.D.

Is this the big bore kit you are talking about? http://www.crfsonly.com/catalog/product ... ts_id/1768

What is this 89A cam you speak of? I can't find it here? And what valve springs should I use with it, stock 230 springs or specific to the 89A cam? Sorry for all the questions, but my google fu is pretty bad it seems. Thanks






Bam Bam

OK I think I found cam, but has a car mechanic I would think a cam for a 150cc would be too small for a 230 (or 240cc) engine. But I see that this cam is pretty big actually.

http://www.webcamshafts.com/pages/motor ... 04656.html

What about using the BBR Rev boxes too? are they good?
http://www.crfsonly.com/catalog/product ... cts_id/329



Bam Bam

Trust me the Web89A cam, though not marketed as a 230 camshaft, works great in the 230 and it can be run with the OEM springs (as long as they are in good shape). Personally, I wouldn't change the cam without changing the springs. Re the rev box....by itself its value is questionable but with the cam and hi comp piston its performance enhancement is more apparent. Basically what it does is change the ignition curve so that it revs quicker and longer before it hits the limiter. (every little bit helps.) While you have the head off, consider porting or having the head ported. At the very least, match the intake port to the carb manifold... again that every little bit thing. You can do lots of little things that add up to big improvements in the 230. There are other informative forums out there which have also been excellent resources for me. Keep searching and come back and share.
O.D.