Dirt Rider Magazine

Yz125

I have a yz 125 I was running a 53t sproket changed it today to a 48 .i turned it only left quick rode it for about 15 -30 then all of a sudden my power dropped no power band no idle .? I changed the gas put some 91 40:1 still same it revs up loud in neutral but no while running ..

*:No power band,
*:Hard time starting
*:115 compression
:put a 48t sprocket
: weird noise in engine
: very weak
*:no idle
Was running perfect at first till like 30 mins in it started doing all that .. ?

Any guesses ?
' Thanks

MJP68

Time for a teardown.

compression is low and symptoms match a very worn or damaged top end.

sean

Ebay

davidcullen90

Do you mean it's hard to start as in its hard to kick over? Or it simply won't start. If its hard to kick, your kick starter might be locked, or you might need a bottom end rebuild (yikes). If you just have low compression, than its most likely top end. It also could be something as simple as your air filter, when's the last time you cleaned it? What does the weird sound sound like?

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