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Help jetting for FMF mega bomb T4.1
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Posted by: yjk

I need help jetting a 07 450er stock. I'm installing a fmf mega bomb pipe and factory 4.1 muffler. Has anyone ran this set up and what did you do for jetting.

also stock air cleaner. recomendations for cleaner would be nice also.

thanks, yjk

Posted by: TRX450R_Racer

Do you run with or without the air box lid?

Posted by: yjk

right now its stock, I would like to open the air box up. I read a post on modifing the air box lid with a outer wear cover. This looks like a good way to get more air flow and still keep water out.

If this is the case, I'll give it a try.

Let me know about the jetting.

Posted by: yjk

I need help jetting a 07 450er stock. I'm installing a fmf mega bomb pipe and factory 4.1 muffler. Has anyone ran this set up and what did you do for jetting.

I'm also installing an HRC Cam this week. Right now stock air cleaner open lid with outerwear. recomendations for cleaner would be nice also.

Posted by: NickG5755

i personally liek Twin-Airs...the pro-flo kit is nice...makes sure the filter is sealed to the boot...

Posted by: yjk

Well I installed a curtis air filterw/ ring. I'm going to start with a 165 jet.

I hope this gives me a good starting point. If anyone has a better idea let me know.

yjk

Posted by: patrickj75

I was at a 180 main and 50 pilot with no lid and a cam and pipe. we're at roughly the same elevation.

Posted by: yjk

Thanks,

I'll increase the main to 180 and see if that helps. What did you do to your needle settings.

yjk

Posted by: patrickj75

i believe i was in the middle to start. my fuel screw was around 1-3/4 turns out.

Posted by: yjk

Well, I spent a lot of time this weekend to jet my beast.

where i ended up at is this

main jet 170
needle 3rd clip
stock pilot
overflow jet 50
air screw 2.5 out.
adjusted the accelaretor pump to the HRC kit spec

my low end is good, mid range alittle sluggish, top end seems to feel like I'm hitting the rev limit, but i know i'm not.

slight popping on deceleration when letting off at high speed.

Any suggestions on what to do next.

Posted by: Bok Choy

Try a smaller main like a 165 and a smaller leak jet like 45 or 42.

jeff

Posted by: mak400ex

My bro told me to run 91 octane. try it - hope this helps..... i know it can be a pain in the *** trying to dial one in.