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Aftermarket exhaust & carb options

45K views 126 replies 30 participants last post by  flyhunter3825 
#1 ·
As many of you know, I have been fighting the idea that you can't power-wheelie a tw. So.... I picked up a 55t sprocket and was thinking maybe a new exhaust and re-jet with airbox mods might wake the little beasty up. I know that the exhaust wont do much but if it helps at all i'm willing to go ahead and pick one up. A dg is $160 on ebay.
 
#2 ·
I'm going to try a DG myself. I'm going to see how much I can squeeze out of the stock exhaust first with jetting. When I put the TM28 carb on for some testing it sure seemed to make the front end lighter. The flat slide carb just seemed to "spool up" quicker. I'm hoping that combining the TM28 and aftermarket exhaust will give mine so more pep! I'd say go for it!!
 
#4 ·
I have played with jets and nothing gets me where I want it. Is the tm28 a push/pull carb? I will see what kind of prices I can get for the carb and exhaust from work tomorrow. I wish someone made a full exhaust for the tw. Airbox mod, flat slide carb and exhaust... we shall see.
 
#5 ·
*I can pick up a TM28 for $110 from work. Are there any other carbs out there that I should look into or should I just go ahead and order this one?

*My cost for a DG is $157 for an "o" or "r" series but the "o" won't be available til late January. I'm thinking that I would rather wait til I can get the "o" series. TW200 DG exhausts

*The FMF would be $212.
 
#6 ·
I'm going to take LB at his word and avoid buying an aftermarket exhaust if all it really does is make it louder. I am still going to order the flat-slide carb and see how that does. Can I use my push/pull cable or do I need a pull cable?
 
#7 ·
Might be interesting what MrBracket's dyno runs reveal about carbs, cams, pipes, etc.



In the proper combination there may be some gains to be had. But I'm sticking to my story when it comes to otherwise stock TW's.
 
#8 ·
Yeah i'm ready to see what an actual dyno will say about these. I may get an exhaust eventually but for now I am going to go with the carb. I don't want better top speed, just want to be able to get the wheel up while trail riding.
 
#10 ·
I'm going to start on some carb testing soon, should be next week. I'm going to see on the dyno how much we can squeeze out of the stock carb first with jetting and exhaust. Also gonna pull off the side cover to see if the airbox is creating any kind of loss.



Then, I'll switch to the TM28 to see what kind of gains that will net with stock exhaust and aftermarket exhaust.



When I had the TM28 on there before, I just machined a little adapter to fit into the airbox side, the engine side fit into the stock rubber manifold. I used a whole different throttle tube and cable when I tested it the first time. The standard TM28 is not a push pull carb, just a single cable carb. We are going to build a custom cable we'll include in the whole carb kit that will fit in the stock TW200 throttle tube. You'll just run one cable instead of two. This of course assuming the TM28 is indeed a beter carb than stock. I'm betting it is, when I had it on mine it really felt like the flat slide made it take off quicker. The other thing about the TM28 is that the jets are much eaiser to get, and diffent needles are even availiable...



My "butt dyno" says the TM28 is a good mod, we shall see what the real dyno has to say.......
 
#11 ·
What kind of adapter did you make? It looks like it would be a straight bolt-on. I'm guessing that it just needs a little more length to reach the air box boot?
 
#17 ·
I have run a big gun for about 2 years. Fits with slight mods better than stock. Had to repack it after a month or so, that cost another 80.00. At idle it is quiet, fmfs are a lot louder at idle, Big gun is a lot louder at wot than fmf. As far as power gain I didn't notice anything with the exhaust alone. Here is what I run, and yes very noticable gains, I can smoke the stock tw's off the line and hang almost exactly at top end, but if we accelerate together there is no catching me. Big gun ttr 225, wiseco high compression 1mm over, web cam tw grind, 42 pilot turned all the way in, 120 main with a very small shim on old style carb. Bike runs better than stock at all elevations and from about 50 to 90 degrees. But it took me 3 years of playing to get it there. Most noticable mod was webcam, did that last with some fine carb tuning and it all came together.
 
#20 ·
No clutch needed. When I really get on it going from first to second the front wheel will come up with out effort. I bought the cam that webcam lists for the tw. Not sure what grind it is but that combined with the other mods is noticable to any of the guys that try my bike after riding theirs. I am happy... for now
 
#22 ·
I think I am going to go ahead and get the cam while waiting for your carb and exhaust dyno results. The more I research I keep seeing that the stock exhaust is the best exhaust for our bikes.
 
#24 ·
My tm28 showed up today so i'm gonna try to get it on later tonight and see if it really needs a spacer. I am also going to see if I can just use the pull on my cables and leave the push one hanging until I see if i'm gonna keep it.
 
#25 ·
If your TM28 is the same one I got, you'll need to modify the end of your pull cable to work. I needed the spacer on mine, the TM28 is shorter from back to front. I guess I'm assuming your TW has the pre-2001 carb, I don't have any experience with the 2001 and newer carb. When you do get it on there, I'm betting you will like it
The flat slide almost acts like a pumper carb
 
#27 ·
I love my DG pipe:







Definite power gains, I re jetted and shimmed the needle 2 washers. And my TW with 10,000 if I pull back and give it gas i can power wheelie no prob. Also the sound is awesome. I will make a video for you tomorrow when I go install my new jimbo shield. Plus it looks pretty fricken sweet, i am trying to get the super moto look going on mine. No one will believe me but on flat ground I hit 75mph and it was still climbing. Video soon i promise.



 
#28 ·
I wish I could say all went well but there are a few problems. The main problem being that where the cable comes out of the top of the carb is right where the frame sits causing it to not want to sit upright. Also it could use a 1/4" spacer to make it flush on either the intake or exhaust but for testing purposes it was tight enough.



So heres the list of things I need to get before trying to dial it in: have a spacer machined, longer fuel line and a throttle cable that works better than the one I was experimenting with.



Here is a few pics of the carb





 
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#31 ·
You can see the small aluminum spacer I made for mine in this pic. It's on the airbox side.







I used a whole different throttle tube when I tested mine at first. I have not yet figured out how to use the TW throttle tube with a custom cable yet. I'll do that when I'm done testing with the stock carb.
 
#32 ·
Ok. I see, how thick is that alumninum and did you machine it or buy some type of pipe to cut? Also, how did you manage to get the throttle cable to avoid the frame? It looks like your's goes directly up into the frame.
 
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#35 ·
I picked up a spare set of cables and some fuel line at work today so I will see if I can get the stock tw cable to work. Think you can make me one of those spacers?
 
#37 ·
Alex, Don't worry about that! It will get done and I will be sure to let everyone know if it's really worth the fuss. I'm sure bracket/procycle will put together a nice package that will make it easy for everyone. I guess I just like doing things the hard way.
I have new sprockets including a 55t and an o-ring chain to go on it but I don't want to mix up the results of the carb with the larger sprocket. Btw, i'm pretty sure that it said tomorrow before...




Bracket, I was searching my garage and up at work all day trying to find an angle fitting for it. I know I had a few around here somewhere but they just walked away I guess. I think with the fitting the stock cable will work fine. Needs to be about 3" to take up the slack in the cable.
 
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