I just bought a used Yamaha PW 80 for my son ,he's outgrown his50. It seems to run all right however power drops off at full throttle. I read that a rev limiter may be the cause but could it be the carb? Thank for any input.

I realize this is not KLX related however I value your input.

(Iowaguy, upgrading him to a DRZ400 is not an option at this point although I'm sure it will have more power than the 80cc.)

 

try derestricting the exhaust.

I was going toget my young boy a PW80, but opted for the 4stroke TTR90E, ...Yes it comes at an extra few hundred dollars but i believe the extra suspension travel will see him have it longer than the PW 80.

I deally would have like to get him a green machine like his dads in the KLX 110 - but too expensive.

 

Got the bark busters for him yet? You could always mail order and tell your wife you can't understand why an extra setcame in the box.

 

If the bike has seen a bit of work the exhaust may be oiled up and may need cleaning out.

 

Yeah mate....barkbusters are on their way, some big green ones for me - and a mini blue set for Jed. I couldnt just order stuff for him and not me. Besides the missus is always going on about bargains, well i got both sets for 220 dollars with mounting kit deliverd - thats a bargain.

I also went out and got a new uni filter for both our bikes.....As we are all aware, spending money on bikes is easy once you start!!!!!!!!!!

 

Good deal on the guards! I'm getting ready to mount some Zetasright now that almost almost cost that much for the pair.
Yeah, onceI put my pipe andpumper on, Islowed the mod flood gate to a trickle, but now that winter ishereit's wide-openagain! Once the dusthas settledwith the engine mods, I'll probably be looking at a different air filter and possibly atachometer. TheJapanese models have this nice, digital speedo, but no tach! I can't see going with something like a Vapor just to get RPM, sothe small diameter analogueadd-on tachs are looking pretty good right now. Just got to come-up with the cleanest way to mount it.

 

My son's PW50 had a restricter in the exhaust...I think right by the manifold there wasan extra washer type doohickie or something. Also, the throttle had a retricter screw on it.....don't know about the 90 though.
I found that taking the carb apart and cleaning it helped with the bog he was getting at full throttle.
The air screw was not right-on either, so after some messing around with the two screws,the bike runs very good now. This is all on a 50, so things may be different for a 90.
I'm in the same boat as far as moving up to a bigger bike for the boy......Pw90 is manual clutch,right?
Dave

 

My kid had a PW80, There is a restrictor cone on the end of the silencer that you can cut off (you can't miss it when you remove the silencer), the FMF pipe works better.

Remove the rubber airbox snorkel and re-jet and adjust the carb up correctly.

The rev limiter is built into the CDI box, you can replace the CDI off an old PW80 that does not have the limiter.

The motor also takes well to having the head milled I hear, although I never got around to that.

There are hundreds or tricks and mods for these little bikes, talk to the guys with kids at the local track, they'll hook you up.

 

Thanks guys. I wanted to pick him up a KLX110 but the price kind of threw me. Never see any used ones for sale around here so I went with the 80. In a year or two it will be time to upgrade and I'd like him to have a manual shift so I'll probably spend more then. This bike came with the extender which I removed. I guess I'll pull the carb and clean it, I imagine it sat for a bit as the guy we picked the bike up from had bought his son a new Honda.

The bike pulls me up the lane pretty good but craps out the top so it probably is the carb. Still imporessed that it hauls my 260 lbs around though.

Thanks for the input.
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KLX110's come up all the time on ebay