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Discussion Starter · #1 ·
i have an 07 honda 400ex. i took a used fmf head pipe and i new fmf tail pipe and put them on my wheeler. my question is i put the exhaust on and the tail pipe slips on the head pipe fine but i does not go all the way up on the tail pipe. and when i run the bike i feel a little exhaust coming out of it.


my other question is this same bike. in the carb a had a 168 main and a 38 pilot. well i took out both jets and put a 152 main and a 40 pilot like fmf suggested. feels like when i get pinned in 4th and shick to 5th that i loose power and a speed. so i guess what i am looking for is something to me top end and take off power. so i was thinking about putting my stock jets in and leaving it alone. any idea's. o and my air box lid is stock nothing done to it.
 

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FMF said to go down on the main? You need to add fuel, that means going bigger.
 

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According to my manual, stock main jet should be 148. For some reason it don't list the pilot jet.
 

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Never mind. I found it. Stock pilot jet is 38.
 

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adding a pipe gives you more exhaust out/more intake in meanings you would need more fuel not less, you shoud have a bigger jet size not smaller. somethigns not right. did you have the stock main jet in it to begin with?.. maybe its been changed b4
 

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Discussion Starter · #6 ·
think its been changed before. so i took the 168 and went from the stock which is the 148 so i went to a 152 so in all actuallity i went down from the jet that had been in it before but i went up from stock. when i had the 168 in i had to remove my air box lid, where i ride at that can't work to much water. got any ideas of what to do.
 

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I know dynajet recommends a 170 main down one clip on the needle and turn the air screw out 1/2 turn and remove the airbox for aftermarket exhaust and filter. if that helps???
 

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Agree^^^^^!!!Something with you bike seems screwwy.Why did it have bigger jets with it being a factory exhaust.
 

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Discussion Starter · #9 ·
it didn't vae jetting with stock exhaust. i pulled my carb off the 05 that had FMF exhaust because that was the wheeler i got for my girl friend and that was to much power for her. so i took all the performance stuff off and put it on my 07. and when i road my 07 with all the stuff form th 05 i had to remove the air box lid because it was starving for air. well removing that where i ride is not a good idea. so i broke into the carb found out it had a 168 main and a 38 pilot. so i bought a 152 main and a 40 pilot like FMF advices to do when you put on there products. so i bought that now i have no top end. wheeler isn't starving for air any more but my buddy on his completely stock 07 will catch up to me and pass me on the top end all day long. so what should i do. sorry that was alot and i am trying to figure out whats wrong. Thanks agian for yalls help.
 

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go up a little more on the main cause thats for the topend.watch your sparkplug dont want it white more of a brown.
 

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Alot of factors determine your top end... for example what gears are you running, what tire size on the rear? how was the topend with the 168 jet? have you reset the air/fuel mixture it really sounds like you are running lean on the top. if it's still lagging with the 168 move to the 170 like I suggested. you always want to be a little more rich than lean.
 

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You were running a 168 with the lid off and no FMF pipe, Correct? Put the lid back on and put the 168 in there and see how it does.
 

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No he was running the 168 in the carb on the other quad.It was his girlfriends.It had the 168 and the fmf.
 

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no billy he put a used FMF hread pipe on his and a new FMF slippie and the carb from his gals quad or that's the first post anyway. He's too rich or too lean on the topend, remove the lid and try it, if it get worse then go up on the main jet.
 

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Discussion Starter · #16 ·
so go up on the main to like a 155. o and all the gears are all stock tires are all stock everything is all stock. what should i do with pilot leave it at the 40 or switch it to the 38.

i was running my 07 with the 05 carb that had the 168 main. it seemed like it was gasping for air so i removed the air box lid and worked fine except i had no top end. my buddies stock 07 straight caught up to me and passed me no prob. i will try the 155 anything else i should try.
 

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Keep the 40 pilot.I run a 40 in my 250x.
 

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Yeah that would be fine.Get a fresh plug and once your done run it real hard and shut it off pull the plug and see what color the electrode insulator is.If it's really white it needs more fuel but if it's a tan color or brown your fine.
 

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so go up on the main to like a 155. o and all the gears are all stock tires are all stock everything is all stock. what should i do with pilot leave it at the 40 or switch it to the 38.

i was running my 07 with the 05 carb that had the 168 main. it seemed like it was gasping for air so i removed the air box lid and worked fine except i had no top end. my buddies stock 07 straight caught up to me and passed me no prob. i will try the 155 anything else i should try.
I thought you put the FMF set-up on this quad? if you removed the box lid and it's still lacking power go up on the main jet.
 
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