FMF versus Pro Circuit for KDX220a8


JimVowell

Member
Jul 19, 2001
33
0
I am getting ready to purchase a pipe and silencer. Ive wanted a ProCircuit for some time, but I rarely see one on a KDX. Is there a reason for this. Also, Im still not clear on what will work best, the REV pipe or the Torque pipe. While I dont like the fact that I run out of power in each gear in higher RPM's I dont want to lose the low end torque. Is there a nirvana, more torque and even a slight increase in top end ???? Any help would be appreciated...
 

jimicarl

Member
Aug 7, 2001
102
0
torque vs. rev pipes

for what it's worth.

i ride with a number of fellows with kdx's (mostly woods riding in the great pacific northwest). some ride 200's, & some (including me) ride 220's. all with stock carbs. all with different pipe configurations. i run an fmf gnarly rev, with a turbine core silencer. it's power characteristics are virtually identical to my buddy's 200 with a torque pipe and same silencer. go figure. i have another buddy with a 220, who's running a stock pipe and turbine core silencer. that appears to be the best of the bunch. it's retained it's stonking low end, and added considerable top end. it won't rev quite with mine..., but the difference is negligable and pretty much moot for woods riding.

can't comment on the "other guys" pipes. i've always run fmf's because of their reputation for working without unduly sacrificing some part of the power.

have fun!
 

JimVowell

Member
Jul 19, 2001
33
0
Thanks...Sounds like I can go with the Silencer first try it and then move to the pipe if I want more top end...Thanks again...
 

canyncarvr

~SPONSOR~
Oct 14, 1999
4,005
0
fmf vs? PC

Please do some more checking on this board regarding fmf stuff.

A number riders have taken exception to fmf's:
1. Poor fit (sometimes NO fit)
2. Missing mounting hardware
3. Poor construction (bad welds)


Most 220 riders choose the KG-30 (fmf rev) due to the 220's existing excellent bottom end, but restricted top (largely due to the small carb).

I have both pipes...use them in different riding conditions. I prefer the KG-35 (fmf torque) on my bike largely due to it not BEing large. The rev pipe, comparatively, is huge!

My riding buddy runs an fmf TCII, I put on a PC. After that particular mod (other things between the bikes being identical), the bikes remained dead even through a six gear WOT run.
 

JimVowell

Member
Jul 19, 2001
33
0
Thanks for the info.... I really like the power band on the stock but need just a bit more on the top. I dont want the bike ripping my arms off like my buddy's CR250 , but I really like to ride desert trails in Vegas (not a big motocrosser), however sometimes I do hit the track...
 

canyncarvr

~SPONSOR~
Oct 14, 1999
4,005
0
more on top

You'll get that with a 36mm carb. You have a 33mm now (given that it's stock). The 33 can be bored to 36.

After you get your pipe setup, if you want summore spit on the top, you might consider either a carb bore or an R&B Designs carb mod.

You haven't mentioned it, but I assume you've been to CDave's JustKDX site to check out the hopups section? Things like airbox mods? Correct jetting can help a LOT in your bike running better all 'round.

http://justkdx.dirtrider.net/
 

JimVowell

Member
Jul 19, 2001
33
0
Yeah, the Hop up guide has good stuff in it. I think Im just over anlalyzing it,,, Im going for the Pipe/Silencer, Air box mod and then check it out. if I need more Ill do the Carb bore thang...Thanks for the help....
 

jimicarl

Member
Aug 7, 2001
102
0
hopup mods

good things come from the great state of jefferson (like MRA's little hill at jacksonville). as you try stuff out; take a hint from someone who's learned the hard way..., ONE THING AT A TIME!! if you make two or more changes between rides..., you'll never know which change had what affect. have fun trying it all out, and keep us posted on what you learned.
 

Fred T

Mi. Trail Riders
LIFETIME SPONSOR
Mar 23, 2001
5,272
2
FMF KG 30

Best bang for the buck...
Put a KG-30 rev pipe on it, keep your stock silencer, add Boyesen reeds, drill holes in the air box lid and toss the snorkel. Get the jetting sorted out. Then work on the suspension -balance the front & rear springs. (Call MX Tech for that) If after that you want to go faster consider revalving the forks and shock.

If after that you need more power then mod the engine more, port it, bore carb and change out to Weisco Piston. Then add a FMF turbine core II silencer but chances are it won't fit real nice like the stocker.
 

fishhead

die you sycophant !
LIFETIME SPONSOR
May 22, 2000
966
0
I put a set of boysen reeds, a kg-30 rev pipe and a tc-2 silencer on my 220 and i didn't feel i lost a bit of bottom end but did pick up some over rev on top. (hold each gear longer)

if you want more rev then bore the carb and add a rad valve. some have panned the rad valve in this site but i found the increase in over rev on my 220 to be about equal to the gain found when changing the pipe.I didn't try the rad valve until after I bored the carb.

if you are going to be riding at high revs then it would good idea to swap out the piston for a wiesco, stockers have been known to frag motors.
 

JimVowell

Member
Jul 19, 2001
33
0
Thanks for the info and the Wiesco tip. I let my bro ride it sometimes and he is WOT all the time (he used to ride PRO motocross). He needs to get his own damn bike... :cool:
 

JCV 220R

Member
Oct 13, 1999
90
0
the fit and finish of the PC pipe is excellent but the performance is a joke. Either FMF pipe would be your best choice but I prefer the T pipe with a bored carb

On a KDX, suspension mods will make you a lot faster than getting more power. The KDX is in serious need of suspension work and if I had to do it again, I'd put my money there first.

Just an opinion from someone with a few years and few thousand dollars into a KDX
 

JimVowell

Member
Jul 19, 2001
33
0
Thanks for the heads up on the PC pipe, and I have already replaced both the Forks and the Shock spring with Race Tech mods. I have not gone the valves yet because the proper springs have made a world of difference, especially with my lightweight body (235)...
 

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