i have been doing alot of modifications and never had a problem with it cutting from quarter throttle to wide open It started with my last mod putting the 400 ex boot in place of the stock I also have a really big k&n 5 by 8 inches I have ran through the jeting and tuned my exhaust with the disces cause I have a ct pipe and nothing has made the cutting out any better the only thing I could think of is maybe the caburator cant keep up anymore with the mods any Ideas would be great Im new at this fourm so Im trying it out thanks.

 

You might want to go with a bigger carb. Why did you go with the 400ex boot? Only used when people go with larger carbs. Try going back to old intake boot and you should not have any more problems.

 

are you sure its jetted right??

 

well the reason I went and got the ex tube is cause my friend has a ltz 400 07 and is running a pretty similar setup exept stock compression piston and he got his dialed in perfect before it was too much for his carb and I have the tuneble exhaust so if i needed to i could d tune the air flow to get the peak power out of the carb but i found out recently that his year quad had an upgrade on the carb mine is a bsr 36 and his is a bsr 37 just a tad bit bigger just enough so im looking for a keihin fcr 39mm carb and that should fix the problem I did get it tuned with everything to run decent a little lean but rideble thanks for the advice though.

 

Could be a lot of things but it sounds lean to me.

 

I agree, you've got to put in an oversized jet.

 

I have already been from a 165 main jet to a 195 main jet and everything between same as the pilot and the needle has been on every clip with every main and pilot from stock to a a 40 I ve spent hours and hours on jetting right now I have a 175 main 30 pilot 1and half turns out on the mixture screw and its running ok but still wants to cut out a little oh and the clip is on the 2nd slot i think its always had this problem but now that i opened up the air flow massively that its made the bogging and cutting out way more noticble only the bottom end though the top end raps hard and smooth even when I had the 195 on the main but the low end was horrible then so thanks for all the advice i appriecate it Im just going to keep tring new things until i can get my fcr 39mm curtis sparks carb