i bought a curtis sparks motox pipe for my honda 250r. (310 pro-x kit). anyway, i took my fmf fatty pipe off because it has very little top end power. it pulls strong on the bottom and midrange but does not have any top end. the sparks pipe has no bottom end but rips thru the mid range and on top end. my bike is alot faster with the sparks pipe (straight line drag race) but slower on the track. i'm going back to my fmf fatty pipe for now. with the sparks pipe on i have to slip the clutch to get the rpm's up to pull 4th and 5th gear jumps. with the fatty pipe it will just pull like a tractor, but you have to short shift it or it will stop pulling. anybody else find a pipe they like better than the fatty? maybe the new sst fatty pipe from fmf. thanks, airtime

 

I have an FMF fatty on my 86. It's OK. But it's strange, I feel mine actually hits a bit late...like it has very lowend. I have a thread somewhere in here called "My R is slower. What is wrong?" I'm still working on it. You lack top end too? maybe it's the pipe. we'll see.

anyway. My brother just put an ESR pipe on his and wow! his ran well w/ the stock pipe and now it really rips. It hits slightly later than stock but not much. Take a look at theirs. I for one was impressed.

Some others I'd check into the Pro Circuit mid range pipe. I know they make it for the CR but I'm sure about the TRX. Another one is the FMF Gnarly pipe (again, check availability for ATVs):it actually loses a bit of top end but really boosts lowend and midrange (i.e.torque pipe). Oh, LRD makes an adjustable pipe so you can tweak your powerband by twisting a screw while it's running! Sounds cool. I wanted one for my KXF but they didn't make one.

These are some non-pipe things I've done or having done to boost lowend and midrange on my KXF. They really work!-----> lower exhaust port slightly, widen the ports (not porting!!!) and change your sprocket ratio for more lowend (I liked this one alot).


I was reading on lukesracing.com about a cool mod to boost lowend. It involved using a thinner, I believe, "base ?" gasket (where the topend and crankcase meet I think). This lowers the head slightly (I'm talking needing a micrometer to see the difference) really makes the quad hit faster. You do the opposite for topend. I think I'm gonna add this mod to the work that I'm having done right now. I better hurry up and tell him before he finishes!

Well, I hope this helped. I've done some research on boosting lowend without porting for my Tecate 4 (which has less lowend than the 250R stock to begin with). So these mods are fresh in my head. The ones I've done already really work ( I smoke R's on a holeshot by 2 or 3 quad lengths) and the ones I'm having done are being done by a pro rider w/ a tecate 4 and suggested the rest and he's doing the work. That gasket thing I read on that site and the guy working on my quad said it's very true. so, there you go! good luck!

 

Which ESR did he get? TRX5, TRX6, Zepplin, TRX11 ???

 

trx5

 

Sweet, I love my TRX5's top, mid power.

 

<< i bought a curtis sparks motox pipe for my honda 250r. (310 pro-x kit). anyway, i took my fmf fatty pipe off because it has very little top end power. it pulls strong on the bottom and midrange but does not have any top end. the sparks pipe has no bottom end but rips thru the mid range and on top end. my bike is alot faster with the sparks pipe (straight line drag race) but slower on the track. i'm going back to my fmf fatty pipe for now. with the sparks pipe on i have to slip the clutch to get the rpm's up to pull 4th and 5th gear jumps. with the fatty pipe it will just pull like a tractor, but you have to short shift it or it will stop pulling. anybody else find a pipe they like better than the fatty? maybe the new sst fatty pipe from fmf. thanks, airtime >>



Did you do a proper plug check, and re-jet after changing pipes?
Different pipes most often require different jetting depending on their scavaging efficiency.

 

yeah, i have changed jets, needles, and carbs. nothing works. i went from a 85 main jet with the fatty pipe (58 pilot)to a 70 main jet on the sparks pipe to get a descent reading on the plug. i ran my bike a little chocolate color on the plug with the fatty and it still had plenty of low end grunt. it idled well with out any problems. the sparks pipe is nice and i'm not downing it, i have just not had good luck with it. maybe because i'm running a stock pro-x compression ratio of 160 lbs cranking pressure. maybe if a ran a 220 lbs cranking pressure it would help. i don't know, but the sparks pipe is coming off and the fatty is back. has anyone tried the fmf ssr pipe? thanks airtime. also the sparks pipe is for sale. it's chrome and about 4 months old. i'll take $350 for it and the silencer.

 

i have read CT Racing makes the best pipe for a 250r they make two pipes one for all around riding and for dune riden the whale pipe is sick on top end i have a 88r 270 with whale pipe on it.

 

dude if you want to set your pipe up dose not matter what kind of pipe you need to DYNO it and see where pk hp is and for trq changin the dome size will change the pipe power band so you just need to dyno it and change **** around see what works for you dont give what you think it needs give the motor what it wants. hope that helps got any ? hit me up if you need any help

 

FMF Racing - Pipes

The FMF SST should favor the mid to upper range, and the Gnarly should favor the low end. Your Fatty should be more of an all arounder.

You want top end, so switch to the SST. What silencer you choose to run, will make a difference as well.