99 125sx possibly low power?

Americanricer87 · 06-02-2010, 11:57 AM

Hello everyone, i'm new to the 2stroke world, and i just picked up a 1999 125 sx, I was told it had 1 summer on a top end, so i picked it up, my friends have had bikes for years, they say it has low compression. the bike starts on the 5th or 6th kick, and fires up hot instantly. I can turn the engine over via the kick start lever by hand and can't hardly tell where tdc is.

So while the bike is running, 1st gear the bike spins, second it doesn't have the power to pull the wheel up, and if you clutch it up it doesn't have the power to keep it up. My question is I don't know how much power a 125 is supposed to have. can anyone help?

Americanricer87 · 06-21-2010, 01:25 PM

I've been riding the bike for a few weeks now, I talked to the previous owner, he said he used 25:1 mixed fuel, Well I've talked to several riders and it seems 40:1 is just fine. The bike is running alot better, starts on the first kick cold, still spits alot of oil out of the exhaust, which is slowly becoming less.

ILS · 06-21-2010, 02:24 PM

I haven't had a dirt bike in 12 years. But I do know your bike is in need of a top end over haul. It should be beating you in the face with the handle bars. Unless the other owner changed the sprockets too. I rode a old CR125 like a 96/97 model last year and that thing was scary quick. Yours should be too. As for the oil I always used Klotz. Manufacturers instructions first then play with race oils.

Americanricer87 · 06-23-2010, 01:13 PM

Quote:

Originally Posted by ILS

I haven't had a dirt bike in 12 years. But I do know your bike is in need of a top end over haul. It should be beating you in the face with the handle bars. Unless the other owner changed the sprockets too. I rode a old CR125 like a 96/97 model last year and that thing was scary quick. Yours should be too. As for the oil I always used Klotz. Manufacturers instructions first then play with race oils.

I went to run it today and she died on me and now there is no resistance what so ever on the kick start arm... I guess it's time to pull it apart and put a new top end in her...

Americanricer87 · 06-25-2010, 11:02 AM

Its nothing but bad news... parts of the c-clip for the wrist pin broke and got wedged in between the jug and the piston causing this....

bajadog · 06-26-2010, 09:35 AM

Wow!

The piston is trashed, but I know on the bigger two strokes you
can re-sleeve the jug.