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Replacement muffler

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The boy thinks he needs a new muffler,lol how does the fmf4.1 compare to stock?im gonna leave the factory head pipe in place.

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Unless your current silencer is damaged,

convince him new tires make more of an impact on performance.

Edited by mlatour

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I would,but we just put new tires,had the suspension done,and installed an R&D power bowl.

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A different exhaust changes the jetting which may be more trouble to sort out than it's worth for minimal performance gains.  I was told by at least one owner that all they did was chase jetting issues after they changed exhausts.  We have an older FMF megabomb system and it is cracked in a couple places and we can't keep screws in the can because the holes are worn out.

Like they said, For more power, try a piston/cam.  The PC piston/cam/spring combo is great but $$$$.  We got ours with the bike.  The Fox suspension is also much better than stock, according to my son.

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Right off the bat we had to go to a 45 pilot cause ours wouldn’t start very well with the factory 38.now we’re running a 42 but may try the 45 again since we’re 3 1/2 turns out on the fuel screw. Dean at r@d said they had good luck with the 38 at 4 turns out on fuel screw,but that didn’t work for us

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The further out you run the fuel screw, the fewer threads are securing it inside the carburetor.

At this point, even if it runs fine you should switch to a #45 and get it closer to 2 turns out.

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Normally I would agree, but with the flex jet fuel screw it seems you can run it farther out, plus it seems to meter fuel much better than an aluminum one.

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2 hours ago, Minidad1 said:

Right off the bat we had to go to a 45 pilot cause ours wouldn’t start very well with the factory 38.now we’re running a 42 but may try the 45 again since we’re 3 1/2 turns out on the fuel screw. Dean at r@d said they had good luck with the 38 at 4 turns out on fuel screw,but that didn’t work for us

Interesting!! I spoke with Deal and he told me that he had good luck with the 38 @3 1/2 turn out, however it depended on the specific gravity of the gasoline. Not sure if you told me, however what gas are you running?

 

8 minutes ago, Minidad1 said:

Normally I would agree, but with the flex jet fuel screw it seems you can run it farther out, plus it seems to meter fuel much better than an aluminum one.

Also, are you running his flex fuel screw?

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Yes I’m running the flex fuel screw,other than fuel it might be an east coast thing vs west coast,as I live in kentucky.

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9 hours ago, Minidad1 said:

We are also running pump gas 93 octane

OK im east coast running 100 pump gas. I ordered all the jets and the R&D bowl this evening and will let you know how it works out in the next few days. I have had quite a bit of experience with the bowls and im hoping it works out like I think it will. Thanks for the responses.!

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19 minutes ago, Wes Woodin said:

OK im east coast running 100 pump gas. I ordered all the jets and the R&D bowl this evening and will let you know how it works out in the next few days. I have had quite a bit of experience with the bowls and im hoping it works out like I think it will. Thanks for the responses.!

I hope it works out for you like it did us.all I done was put the bowl on warmed it up,set the fuel screw,took it for a ride myself and almost looped out it came up so fast.i wasn’t expecting it to work that well.

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13 hours ago, Minidad1 said:

I hope it works out for you like it did us.all I done was put the bowl on warmed it up,set the fuel screw,took it for a ride myself and almost looped out it came up so fast.i wasn’t expecting it to work that well.

Should have everything installed Wednesday night and will update.

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