Author Topic: YZ125K Rebuild  (Read 30505 times)

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Offline sleepy

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Re: YZ125K Rebuild
« Reply #225 on: November 29, 2017, 10:38:04 AM »
Using the BTDC method for the stock ignition is the most accurate method but you still need to check that the retard at the top end is working as it should or you could have another failure. Simple check for that is aim a timing light at the marks and if they don't line up at 9k it is faulty.
With the PVL until you know exactly what the timing curve is with your 5000 wind stator any sort timing check below 8 or 9k is asking for trouble.

Interesting how you had the same failure with a cast piston as you did with the Wossner, guess that it wasn't the fault of the Wossner after all.

Offline alexbrown64

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Re: YZ125K Rebuild
« Reply #226 on: November 29, 2017, 11:45:02 PM »
Thanks for all the input guys. I'm working away for a while so I've had to put the bike aside. I did achieve a bit though. I reassembled the engine with another new piston kit, and took the lot up to get measured and checked over.
Also ordered a genuine stator and coil, and have a spare Yamaha cdi.
Will do leak down test, timing light check and use my new standard size carb with Yamaha spec jets. The newer Mikunis may be a whisker different, but I am sure I will be in the ball park.
I will do all these mods, together with the recommendations and mods that Ray Easson is doing in regard to squish and compression.
Hopefully I will have a runner in the new year..

Updates later...
Cheers,