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Trouble reaching the Top End...

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Was out riding solo the other day and was having fun on some short and steep hills. Suddenly, the bike started acting very strange and I immediately headed for home (to not get stranded). The trip home is a 1 mile sprint down the road.

It was on a new plug (fouled before my ride). Was the second ride on a clean air filter. Gas is only a couple weeks old.

The bike seemed to have trouble reaching the top end. It would get there but it fought it. I would give it throttle and it would slowly ramp up until it finally got there.

The other NOTICEABLE SYMPTOM was a lot of popping when I let off the throttle and was coasting. Being a 2-stroke, some popping is normal. This was extreme...it made the bike 'bounce' when coasting.

I'm afraid to go out and try it again as I don't want to seize things up and cause serious problems. I have a feeling many are going to diagnose a stuck powervalve. That may be the case but is there anything else I can check? Is there anything that could cause more problems if I ride it again to try and diagnose (rings, piston, bottom end, etc)?

I may try to ride it again so I can provide a sound clip to assist in the diagnosis.

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I should also point out that I am likely in need of a new top end. I am hoping to make it until fall (couple months) before the rebuild. If it was the top end going, would things change so suddenly?

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I should also point out that I am likely in need of a new top end. I am hoping to make it until fall (couple months) before the rebuild. If it was the top end going, would things change so suddenly?

Well i think you answred your own question lol:busted: Yes the top end can go just like that. I would rip it apart before you do any serious damage:thumbsup:

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She's coming apart tonight. I plan to pull the head off and examine the piston. I have never done that on this bike (or any 2-stroke). What do I look for or how do you know you are ready for a new top end?

Do I need to pull the cylinder off or just the head?

I'll clean out the carb while it's off.

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Take off the head and the jugg. If you have a mic and specs thats all you`ll need to see if its bad. Most times when you take it apart you can see if there is a problem right away. Good Luck

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Take off the head and the jugg. If you have a mic and specs thats all you`ll need to see if its bad. Most times when you take it apart you can see if there is a problem right away. Good Luck

On removing the cylinder, do I need to disconnect the powervalve?

I have a mic but do not have spec's. What do I measure? I can post up my results.

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On removing the cylinder, do I need to disconnect the powervalve?

On the 200 you just lift the cylinder off. The power valve actuater gizmo kinda slides in and out of it's spot. nothing to disconnect like on the 250/300.

It sounds like a clogged jet or something, but could also be a sticky pv.

I don't ride that hard, so I know i'm ready for a top end when I finally get around to it after a few hundred hours of riding.

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if I was going to through the trouble of tearing one down, I would go ahead and do a top end just to keep from having to tear it down again.

I am curious as to what you find. I haven't needed to or had the gumption to pull one apart yet. :) to ya.

llama, braggart.:worthy::D

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While you have the cylinder off-look over the bore and the exhaust ports closely. I just got my head cut and some porting,new piston,etc. (on a 2008 200xc) There were some obvious casting flaws on the exhaust ports right at the bore. Bike had maybe 30 hours max. Seems quality control is a little off.

Nto sayong this is your problem,but if you fingd the top end worn-things like this can be attributes. Good luck

Oh,if anybody is interested the porting/headwork and stiffer reeds really made my bike have some serious power. I gotta run race gas,but the power is outrageous!!!

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I pulled the carb today and gave it a good washing. Sprayed out all the orphices dirt could hide. I also pulled my air filter because it seemed heavily oiled. I threw in a brand new plug and fired it up.

IT RAN PURRRRRFECTLY! I think I had two problems facing me: a dirty carb that was blocking a jet and not allowing it to hit the top end; and a over oiled air filter limiting the air flow and fouling my plugs (and causing a butt load of smoke).

I'm going to continue with the same top end and plan to rebuild during the winter - if it makes it!

All in all a pretty good day! I also got the window working on my Tacoma :)

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