Fmf pipe

[PretendOstrich]

what is the best one?(most power best sound and the most responsive :uh:

 

[mmz77]

Go to their website and research what range you want to increase, smooth out etc. Some increase top end, increase bottom end, increase all around - you just need to specify what you need or are using it for. :cool:

 

[souphmars]

i have an sst with a shorty silencer- i have had it on there ever since i got the bike- i like it

 

[chevyss_98]

i gots a FMF gold fatty with silencer on it, helps out alot with bottom end, Very expensive tho, personally if i had it to do again i would stick with just doing pro-series reeds and a wiseco piston, good bang for buck, but if you got extra money, go for the exhaust

problem is, it can be a HUGE hassle to jet the bike sometimes, i know i had a heck of a time with mine, but now..... perfect :D............

SST is also good from what ive heard

 

[BigRedAF]

For a 125 I would lean towards their SST model with what ever silencer they say works best. However, since I didn't want to throw out some crap that I hadn't tried I thought it was best to do a little research. The link below has a pipe test on the RM125 and they choose the Pro Circuit combo over all FMF models, Bills and Dorma's.

http://www.dirtrider.com/tech/141_0302_2003_two_stroke_exhaust_test/index.html

 

[wake_rider]

The sst is a great pipe, but be careful. I've heard a lot of cases where people have had detonation problems if they had to run a lower octane fuel. So i guess, if you run it make sure you bring enough of your own go juice so you don't ever have to borrow any from someone else. You never know what they are using or how long it's been sitting.

 

[BigRedAF]

The sst is a great pipe, but be careful. I've heard a lot of cases where people have had detonation problems if they had to run a lower octane fuel. So i guess, if you run it make sure you bring enough of your own go juice so you don't ever have to borrow any from someone else. You never know what they are using or how long it's been sitting.

Interesting comment?

I'm not sure at the moment how a pipe would raise cranking pressure and cause detonation. They're generally built to increase scavenging and reduce back pressure for an increase in performance.

 

[wake_rider]

Interesting comment?

I'm not sure at the moment how a pipe would raise cranking pressure and cause detonation. They're generally built to increase scavenging and reduce back pressure for an increase in performance.

I wish I could tell you. I had been looking into an sst for my bike but a large amount of the guys that race in OCCRA (oklahoma cross country racing association) all said this exact statement to me. I really don't have a good enough understanding of the scientific effects expansion chambers have to even start to try and identify why this could happen. I just had multiple people step up and say it was a GREAT pipe in the sense of power gains, but many had issues with it and it seemed just a little too volatile for my pocketbook.

 

[BigRedAF]

Roger that...

There's a lot to designing pipes and two strokes work off waves and other good stuff that's above my pay grade. I just thought it was an interesting comment.

 

[hot125mod]

eric said that a messico gp pipe is the best pipe made for the rms I would like to try one. I am guessing it responds like a pc but probably a larger center section for some better top not sure though.

 

[souphmars]

i also have v force reeds with the sst pipe and shorty silencer- i have never had problems- when i first gotthe bike it had a flywheel weight on it- i took the weight off a while back, and still have had no problems- from my personal experience i like it, and i would recommend it

 

[125rmcrazy]

it just keeps heat in the pipe longer. backing everything up causing combustion chamber temps to rise. higher operating temperature is more prone to detonation in any given instance, especially when the bikes already almost on the edge stock.

 

[hot125mod]

i think i contradicted my self i dont think a pipe with a large center section can respond like one with a narrower one does any know how the overall length affects the powerband. BTW what is the tuned length? example

 

[BigRedAF]

Exhaust waves move at a speed based on heat and pressure. This is the other stuff that I mentioned being above my pay grade.

If a builder gets it right then it works great. If they don't then your pipe will be junk.

A lot of unburnt fuel goes through a two stroke engine. Some of it gets stuffed back in from the expansion chamber cone design. How much is an other part the the build process that I don't understand.

Perhaps Eric can chime in on this topic and clear it up for us.

 

[ignition retard]

Interesting comment?

I'm not sure at the moment how a pipe would raise cranking pressure and cause detonation. They're generally built to increase scavenging and reduce back pressure for an increase in performance.

I found this animation on the internet, it sorta shows that if the pipe is timed right that it would pull fuel and air out the exhaust port then jam it back in on the upstroke thereby increasing cylinder pressure. Maybe to the point of detonation, idk.
<img src="http://www.liebold.com/rumipages/espansioni/two-stroke_c.gif" border="0" alt="">

 

[BigRedAF]

A lot of unburnt fuel goes through a two stroke engine. Some of it gets stuffed back in from the expansion chamber cone design. How much is an other part the the build process that I don't understand.

Kind of what I said... Nice illustration. :cool:

 

[ignition retard]

Yeah, I posted that, not seeing there was a second page to this, when I looked for my post I saw it was right under where you already said that. then it was too late, ha ha