Interesting...What size main jet are you using and what setting is the C clip on? Do you have the pipe welded or are you using the tubing it comes with? How long is the header?
SBP Pipe good first upgrade?
- Thread starter SD moto man
- Start date
Wow. 37 mph. That's dang near 40. Movin pretty quick down there! Wondering a couple things. Sprocket size? Bike type? your weight?
Head pipe is too long, chamber is too far away from the exhaust port for max gains. I used a copper flex pipe ment to hook up hot water heaters. That way you can make a sharper turn out of the head pipe and about 12" to the expansion chamber. That piece of tubing is where and how you tune a expansion chamber. You can't just stick one on and expect WOWZA performance gains without tuning. The exhaust systems where you see a chamber at the end of a long skinny pipe are a joke, you'd be lucky to get 10% of the power your looking for
Best part of it is it makes the mods you do later work to their max potential. You have to not think of individual pieces but as a balanced package.
O.k. thats what I was figuring. When I first saw the expansion chambers on these bikes i was surprised, and didn't think they looked right with such a long headpipe. Motocross 2 strokes have very short taper expansion chambers with little headpipe at all.
I wonder if we could get FMF to make a pipe! that'd be awesome...
I wonder if we could get FMF to make a pipe! that'd be awesome...
Dogtown...I had talked to FMF about a custom chamber at one time and the price quoted forced me to make my own. The problem with getting something that works is the fit and finish. No two bikes and motor install are the same. I have been asked to make chambers before but declined due to not having the bike present.
You might have good luck if you use the stock pipe and modify it, then jet the bike correctly and run the air cleaner Norm suggested.
On a side note: you will never get the performance from this kit motor like you had from your dirt bike days...we all wish we could...Morini might be the only answer and I know someone local that might get off it for the right price...lol
You might have good luck if you use the stock pipe and modify it, then jet the bike correctly and run the air cleaner Norm suggested.
On a side note: you will never get the performance from this kit motor like you had from your dirt bike days...we all wish we could...Morini might be the only answer and I know someone local that might get off it for the right price...lol
Ya man, totally makes sense. I think for now I'm gonna just use this SBP pipe and make the header fit to the build, which will take a couple inches off the kit headpipe, hopefully optimizing a little power, Jet it accordingly and go with that. I can't expect anything miraculous out of a 66cc Chinese no name (supposedly RAW, but apparently that's even questionable) engine anyway. It's all about the novelty for me. thanks for the feedback!
and I think I know who has a morini sitting around..
Hey Dave, thanks for the feedback! do you think the ridges in that flex tubing are gonna create all kinds of eddies in the exhaust flow? seems like a smooth wall is needed for the exhaust gas reverberations from the expansion chamber to work...Head pipe is too long, chamber is too far away from the exhaust port for max gains. I used a copper flex pipe ment to hook up hot water heaters. That way you can make a sharper turn out of the head pipe and about 12" to the expansion chamber. That piece of tubing is where and how you tune a expansion chamber. You can't just stick one on and expect WOWZA performance gains without tuning. The exhaust systems where you see a chamber at the end of a long skinny pipe are a joke, you'd be lucky to get 10% of the power your looking for
Best part of it is it makes the mods you do later work to their max potential. You have to not think of individual pieces but as a balanced package.
I currently weigh 220. I'm using a Dax RT with a #65 jet thats filed out to about #68 mounted on a modified intake pipe. When I was clocked at 37 I was using a 44T with the engine about to explode it was reving so high, and now I'm using a 36T sprocket and top out somewhere around 38MPH and the revs are pretty low now with the smaller sprocket. If I would tune the pipe further and lose a about 10-20 pounds I'm pretty sure I could go near 43MPH. And the Xchamber is welded solid so no leaks. The length is about factory length just I swapped the copper pipes with the bend from the stock pipe, fits perfect. And it's mounted on a schwinn delmar and I'm using 26x2.00 knobby tires. Bike weighs somewhere around 76pounds. I've got the fastest bicycle in Falls county
Last edited:
Heres some pics. Don't ask why I still have that spring on the exhaust, cause I don't know either.
