Curtis Sparks pipe question...

[mall0y]

Alright heres the story...My friend bought a used 300ex that had a Curtis Sparks X-4 pipe on it. For some reason it was acting and he figured out that he was running really rich at higher rpms. So, what we were wondering is if anyone knows the correct jet sizes for the pipe. We are assuming that the stock jets are in there but we arent sure. Just thought id try here to see if anyone knows. Thanks

[cals400ex]

you need to let us know if it is running rich at 1/8 to 3/4 or 3/4 to full throttle? the rpm range doesn't mean too much. i think the stock main size is a 122, but i am not positive. just take the carb off and see what jets are in there. you could also look at the needle and see what position the clip is on. now, this bike may be using keihin jet or it may be using dynojets. there is a difference. the keihin main jets should have a K that kind of looks like a star by the number. the dynojets won't have this on the mainjets. i would probally start somewhere around a 130 or so on the mainjet given your using keihin jets. you can get these from your local dealer or order them from C&D racing off of this site. however, i think sparks recommneds somewhere around a 135 or so, but i am not sure. i would look in there and see what you have and then try to fine tune.

[Colby@C&DRacing]

If it still has the stock jets in it, then you can bet it is lean not rich. You never said how it was acting up. give us some info and we can help:)

[mall0y]

well its kind of hard to explain. The part where it is acting up is definatley an electrical problem, and he is in the middle of fixing it but, he had a friend who works on motorcycles take a look at it and he said that it is running rich and that is part of the problems. The mechanic also said that with the elcetrical problem it would sputter cut out anywhere past half throttle. I am pretty sure that he has the electrical problems taken care of. All we need to know now is what sizes Sparks reccomends for the pipe. Just the sizes. I probably wont be able to look at it untill next week sometime so im not sure abouw what kind of jets are in it now. Like i said he is assuming they are the stock ones but i agree with Colby@C&DRacing, if anything it would make it run lean. So, do you think he is just best of buying all new jets and just starting over? thanks

[hondarider2006]

if you don't know what jet sizes you need, your best bet would to get the jet kit for the 300ex. That way you have all the jets, and you won't need to go back and forth from the dealer, or wait for new jets to get there. just my $.02:cool:

[300exOH]

Sparks sent me a 135 keihin jet with a stock motor and no airbox lid to run with my X4. I am at sea level. Mine may be just a touch rich at full throttle so you may want to try a 132 main also. Hope this helps.