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Exhaust modifications??
http://www.kawi2strokes.com/forum/viewtopic.php?f=16&t=5828		 Page 1 of 3
Author:  demus [ Mon Mar 18, 2013 6:07 am ]
Post subject:  Exhaust modifications??
Well I'm finding out that building something special takes special skills which I may have to develope.
I've been working on my inherited H2 project and have a a couple questions, I hope this is the right place to post them.
I have never done a project like this, and it interesting!
I am mocking it up seeing what I have and I found the exhaust won't clear the swing arm. I know a great welder and thought it could be slightly modified but then I thought I realy don't know about theses parts and there is a remote chance that it isn't a good idea. It's a spec II exhaust brand new from 1999. Should I modify it or sell it and do seething different? Just looking for advice, thoughts?
Also I am missing one of those spring steel wavy rings that go in the clutch pack, how important are they?
Author:  oxford [ Mon Mar 18, 2013 6:45 am ]
Post subject:  Re: Exhaust modifications??
If you are going to cut the exhaust make sure that you don't add or take any away from the actual chamber itself. You could cut it at one(or more) of the weld joints and rotate to try and get some clearance.
Author:  ThreePipesSmokin [ Mon Mar 18, 2013 6:55 am ]
Post subject:  Re: Exhaust modifications??
oxford wrote:
If you are going to cut the exhaust make sure that you don't add or take any away from the actual chamber itself. You could cut it at one(or more) of the weld joints and rotate to try and get some clearance.

SpecIIs are hydroformed and don't have weld joints to do the mods you're talking about. They would not take well to cutting/re-assembling. I would suggest selling them, they are very high RPM pipes anyway, with porting it would be a real monster, not very street freindly. Contact Walms on this (and every other :lol: ) board for some WTF pipes http://www.3cyl.com/mraxl/wtf/ They come as a cone kit and can be better fit to your application. :mrgreen:
Author:  Ja-Moo [ Mon Mar 18, 2013 1:12 pm ]
Post subject:  Re: Exhaust modifications??
They are just metal, no reason you can't cut and twist. As was said, try and keep the length as close to the same as possible. I'm not sure you want to go through the process of building 3 new pipes and all the welds, when you just have some rotating to do. Don't forget that if your pipes don't "flop" they are gonna to "drop". Chambers need loose rubber mounting at the rear mounts, or they will crack.
Author:  falconman [ Mon Mar 18, 2013 4:57 pm ]
Post subject:  Re: Exhaust modifications??
Since you have an aftermarket (non-stock) swingarm there are no chambers made that will fit. You will have to modify a set or buy a kit as suggested. As far as the wave spring in the clutch most people remove them when modifying a motor. If it will be a street bike I would leave them in to help release the clutch to prevent it from dragging at a stop when in gear. If you are only missing one I would not worry about it.
Author:  demus [ Mon Mar 18, 2013 6:16 pm ]
Post subject:  Re: Exhaust modifications??
I will probably modify the exhaust I have. Seems like the cost of a new one would limit my budget. Everything on this motor is top end orientated, so I am thinking reeds and carbs for now (when I get the $$), modify this exhaust to fit and see how it runs and change it in the future if needed.
While Im on the subject any thoughts on carbs with reeds considering the PHR stage 2 porting and the Spec II pipes. When I first got this bike I had contacted John and asked him some questions, it seems that is "THE" reed kit to use, the other ones I've seen are just plain UGLY, but the carb aspect confuses me, my inclination with this motor is 38mm flat slides, but I really dont know squat about two strokes and again budget matters unfortunately.
Thanks for all the advice, this is one friendly place :D


There are/were spacers in my Suzuki clutch that long ago where thrown out, so I though it might be the same thing with this. I'll run it with the one missing.
Author:  Ja-Moo [ Tue Mar 19, 2013 3:28 am ]
Post subject:  Re: Exhaust modifications??
demus wrote:
I will probably modify the exhaust I have. Seems like the cost of a new one would limit my budget. Everything on this motor is top end orientated, so I am thinking reeds and carbs for now (when I get the $$), modify this exhaust to fit and see how it runs and change it in the future if needed.
While Im on the subject any thoughts on carbs with reeds considering the PHR stage 2 porting and the Spec II pipes. When I first got this bike I had contacted John and asked him some questions, it seems that is "THE" reed kit to use, the other ones I've seen are just plain UGLY, but the carb aspect confuses me, my inclination with this motor is 38mm flat slides, but I really dont know squat about two strokes and again budget matters unfortunately.
Thanks for all the advice, this is one friendly place :D


There are/were spacers in my Suzuki clutch that long ago where thrown out, so I though it might be the same thing with this. I'll run it with the one missing.


I have "streetablized" (< :wtf: ) probably a half dozen or more PHR motors. A drag biased motor is fun for a while, but in the long run, not a lot of fun to ride around with. One thing you really need to check is the static compression. It should be in the 150-155 range. There was a stretch when his compression ratios got up to 180. Todays premium "gas" will not handle more than the stock 150-155 static compression.

As far as carbs go, 34's work great on the street. Some guys like 38's, but they tend to be very finicky with temp and pressure changes, plus you have to be very smooth with the throttle. And if you want my reed conversion, then 34's are the largest carbs that will fit. And some 35 non Mikuni carbs. that makes for a very fun streetable motor.
Author:  scrambler73 [ Tue Mar 19, 2013 9:06 am ]
Post subject:  Re: Exhaust modifications??
Ja-Moo wrote:
then 34's are the largest carbs that will fit. And some 35 non Mikuni carbs. that makes for a very fun streetable motor.



TMX35's fit.. and they're mikuni! :thumbup:
Author:  Ja-Moo [ Tue Mar 19, 2013 11:36 am ]
Post subject:  Re: Exhaust modifications??
There you go! :thumbup:
Author:  BarryB [ Tue Mar 19, 2013 12:09 pm ]
Post subject:  Re: Exhaust modifications??
<- PHR Stage2+ (not fun on street without reeds), 3's0, Moo reeds two years ago - Y'all know how good my H2 runs even at 6,000+ feet.
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