Jump to content
Sign in to follow this  

Ongoing 2001 YZ125 problems

Recommended Posts

Hi,

I have started a few threads here about a problem where my YZ suddenly shut down and failed to restart properly ever since.

It initially had an intermittent spark problem, but I fixed that and it now has a nice blue spark. And so I thought it was job done but still no luck. I have taken the carb apart and cleaned it thoroughly about 4 times now. There is also good compression. When I kick it there is no sign of starting apart for sometimes when there is a REALLY load crack in the exhaust after 10 or so kicks. I don't understand- I have spark, fuel/air and compression?

Share this post


Link to post
Share on other sites

Do you have any another CDI's or coils, or stators you can plug in, to see if thats the problem . Even though it has spark, there could be something in the electics failing, and not working 100%. I had a similar problem you describe, and after checking piston clearance, ring gap, reeds, new fuel mixed 32:1, clean out carb, exhaust header o-rings for leakage, silencer packing, ignition timing, power valves working properly, checked all wiring connections, and put lttle bit of dielectric grease on each connector, etc, ...was mind boggling. Plugged in a different CDI, and ran great. 2 strokes are pretty basic, made of all solid parts ( piston, rod, crank, clutch, trans, etc) and everything just spins around on a film of oil. The carb and ignition are what makes it work properly. Have a couple friends that build / race / dyno 2 strokes, and they have noticed as much as 2 hp loss on a 125cc that needed the silencer repacked, 1 to 2 hp loss on a leaky gasket where the pipe attaches to the cylinder, and anywhere from 1 to 5 hp loss on a new vs old piston and ring, with way to much clearance on the ring end gap. Found oem-cycle awile ago, and between them, ebay, and a searching parts and part #'s on google, can find pretty much anything at a reasonable price. If you look at the Bike Identification on OEM's site, they usually have cross refererence #'s as to what years are interchangable

Edited by yamaha7442

Share this post


Link to post
Share on other sites

I have put in a brand new stator, and tried a new coil, but still no improvement. Embarrassingly, the intermittent spark problem was caused by the CDI connector not pushed in far enough (I spend £100 on a new stator which I didn't need). Maybe all the times I tried with a loose CDI connector fried the unit?

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Reply with:

Sign in to follow this  

×
×
  • Create New...