KDXRIDER.NET

AZRickD wrote:

thebleakness wrote: . . . In my 2003 KDX220 with the head, carb, and reed mods, the rev pipe mutes the bottom half of the RPM range while not doing anything particularly earth shaking or useful in the upper RPM range. Your 220 might be different, but I kinda doubt it, and nobody here has done the research to prove otherwise (or at least they haven't bothered to post during the last seven times this subject has come up).

I've proven to myself that this Fredette-based conventional wisdom on the rev pipe for the 220 is not all it's cracked up to be and might not be worth the trade-off in low-end torque that a fleeting hint of upper revs brings.

This dogma has died.

Rick

I'm not sure the dogma is quite dead . . .

There are a number of factors that would need to be considered, right? I don't doubt your words - better performance for YOUR 220 when you compared the pipes running your 220 down the street.

There's so much more to consider.

Dogma: An authoritative principle, belief, or statement of ideas or opinion, especially one considered to be absolutely true.

Jeb wrote:There's so much more to consider.

Which is the point. People have been citing the 220 & Rev Pipe combination without considering any factors.

Time to brave the Phoenix heat in my garage and put on the stock pipe for the first time and give it a test.

Edit: strangely, I can't get the stock pipe to fit. When I plug the pipe into the Answer silencer, the base of the pipe is a couple inches shy of pluging into the cylinder head. Either the stock pipe is bent or the Answer silencer has something to do with it. It looks to be the same length as the stock silencer. Alas, my interest wains.

Rick

AZRickD wrote: . . . people have been citing the 220 & Rev Pipe combination without considering any factors . . .

While there are plenty of people that laud the rev pipe without having tested others - myself included - I doubt the rev pipe rose to the surface as a preferred pipe based solely on whim . . .

it will be interesting, though, to read your results from more testing.

"Soley" on a whim? Maybe not. But any testing has not been availed to this forum. Yeah, the rev pipe revs, as long as it's not under heavy load -- wherein it's not any better than a torque pipe. This is a function of timing and porting, not piping.

Prior to this, few if any could give any reason to prefer a PC Plat II pipe over an FMF rev or FMF torque pipe. Now there is reason. The FMFs give up too much torque for not enough RPM gain through the gears. If you need an extra 1,000 to 1,500 RPMs in gears 1 through 3, and don't care about moderate (not modest or insignificant) loss of low-end grunt, the FMF rev is the pipe for you. Otherwise, the PC PlatII deserves serious consideration.

I don't know if there will be any more tesing with my now-shelved FMF Gnarly Desert pipe. If I ding it, it's tougher to sell.

Rick

I'd be keen to buy it from you as long as shipping isn't a killer and you are prepared to ship it over. There is a seller on eBay with the pipes for $198+$45 shipping so if we can work out a good price I'll probably get it from you. Then I can do a "KDX 200: Rev vs Torque Pipe. A case study" post.

SOLELY - gee, thanks for pointing that out . . .

Just when I thought the whole pipe scene was figured out...

Anyway I talked to a KDX'r at a motocross race once, he was on a'99 220, he was also running the PC 2. He said he preferred it over the "Rev" style pipes but he also told me he thought the PC platinum pipes are stronger than their fmf counterparts in all RPM ranges - Meaning the PC plat 2 makes more power than the FMF woods pipe.

And TREV: Just by watching your riding style in your videos, I think thr Rev pipe will suit you better. Go for it

KDXer,

I'd be game save for the cost of shipping it to Down-under. That could be pricey. I used to buy Australian (Moyes) hang gliders and they were not as bad as one might think.

I'll send you a PM, anyway.

Rick

Rick - Its generally noted that the Rev profile pipes take a richer jet set than the torque profile pipes. Are you sure that your jetting was still valid with the rev pipe vs the torque pipe?

Oh god let's hope this comparison was done with jetting changes from pipe to pipe...

m0rie wrote:Rick - Its generally noted that the Rev profile pipes take a richer jet set than the torque profile pipes. Are you sure that your jetting was still valid with the rev pipe vs the torque pipe?

AMEN!!

. . . jetting is one aspect a what I meant by "a lot to consider"

I am jetted a bit rich since the temps shot up from 80F to 100F in one weekend. What is the recommended jetting changes from stock to PC and stock to FMF?

. . . jetting is one aspect a what I meant by "a lot to consider"

I have no evidence that anyone else reported those considerations when they said the rev pipe is the way to go, nor has anyone asked them to do a plug chop (I didn't). I think that's part of the point.

If anyone thinks they can get the jetting spot on in Phoenix in the summer when temps go from 70F in the morning to 107F in the afternoon, have at it. They must have a Dial-a-Jet. I don't.

When someone else does a case study to everyone's liking, let me know. So far, nada.

Rick

I used to run both FMF pipes on my KDX 200 and 220 before they were called gnarlys. I preferred the rev on the 220 and the torque on the 200.

I still run an FMF rev on my current 220, and have found it works best for me overall (I was disappointed with off-throttle hit at first; until I adjusted the pilot screw) - the unmatched mid to upper range power allowed me to stay within sight distance of my friends while hillclimbing huge hills in Clear Creek, Ca (they were on CRF 450's). No way would the FMF torque pipe have allowed the kind of peak HP that the rev put out in 3rd gear full throttle of several minutes or more duration. You cannot short-shift your way up long, steep mondo-traction type hills. I guess what I'm saying is that my experiences lead me to conclude that the rev pipe provides the most versatile, usable power for the 220. The stock pipe is a joke once past mid-range rpms.


My brother-in-law on a crf450 could not believe the hills the 220 was making - frankly, either could I -

I can't make comparisons to any other brands of pipe as I have never tried them.

I just received a ron black modified head which I'm sticking on tomorrow, it'll be interesting to see how it affects the overall power w/o the carb mod.

Kawagumby,
Make sure to let us know your thoughts on just the head mod. I know I would be interested.

Rick, bring your yourself and your KDX up to Flag this weekend for the CTR trail day. You can test yourself on Upper-moto with your bike, it'll be fun!

Janik,

Thanks for the invite but I'm volunteering to do trail fixin' with ATR on Yankee Doodle on Saturday. What day is your trail day, where and for whom.

Rick

Rats, our trail day is Saturday meet time at 8:45. It's open to anyone wanting to come up and help out, it was mentioned on AZTT. Maybe next time.

I got a rev pipe today from Monkey Butt. I put the thing on my 220 and first thing I noticed was it fit way better than the torque pipe I took off. I didn't use a single golf word during the install. Pretty cool for an FMF pipe! Anyway, I could only test it on the street around my house, it sounds a lot different. Didn't expect that. It definitly has more midrange. the bike was popping the front end up just before the KIPS would open. then it would go a little flat, so I think the jetting is off there. I'll play around with it and let you know what happens. So far I kinda like it.

i need a lot of help with jetting my 220 i have currently just a uni air filter but im gonna be getting a rev pipe for my 01 220 and hopefully soon after a new silencer (probably turbinecore 2) i need to know how to jet for about 1100 ft above sea level and about 60 to 70 degress F relatively humid also, do i need to get new pilot, main and needle jets, does something just need adjusted,
if u couldnt tell already, this is the first time ive needed to rejet a bike thanks in advance, Sean

Sean,

Forget the turbinecore for now. A 220 has trouble upstream from the silencer that needs attention long before you get to swapping the silencer.

First off , the stock piston is a grenade. Some guys run it without trouble, but a lot don't it can crack and cause trouble ranging from simply replacing the piston, to total engine destruction. Look into getting a Wiseco piston kit.

Second, Ron Black mods the head and carb on these bikes, and the results are incredible. The 220 benefits so much from the head mod that none should be without it. Save your silencer money for the RB mods, and do the piston to keep your KDX alive.