TY 250 crank case

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TY 250 crank case

Postby R80ST » Sun Jan 15, 2017 7:51 pm

DSC04950.jpg (31.28 KiB) Viewed 12583 times
DSC04999.jpg (32.92 KiB) Viewed 12583 times
I bought a TY250 B The gear change was very loose, I took it apart, and the "Stopper screw" was missing, and there was a hole in the casing.
Does anyone has any experience with welding the casing. And then tap in a new thread.

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Re: TY 250 crank case

Postby TrialsRoss » Sun Jan 15, 2017 8:47 pm


I've got two 250B cases apart at the moment, one is good but the other is like yours. I'm planning on making a jig using the good case to hold the broken piece in place whilst I repair the broken case. Do you still have the broken aluminium "stud" that the "stopper screw" threads into? I've just got to work out how to get that cylindrical roller bearing out of the case......

This is a common point of failure on these motors it seems.



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Re: TY 250 crank case

Postby TriCub » Mon Jan 16, 2017 10:39 am

Not the best stuff to weld but it is quite possible. The position of the thread should be easy to find by putting the selector fork in the middle at the drum end and marking the spot.

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Re: TY 250 crank case

Postby Jon V8 » Tue Jan 17, 2017 5:35 am

I built up a TY250D engine last year from lots of junk in boxes under the bench.I had 3 sets of crankcases to choose from,all 3 were damaged. The pair I used were badly worn on the LH case where the shift shaft comes through, the RH case was cracked where it had suffered impact damage.
The shift drums were all broken too,where the pins go through on the clutch side end.Maybe I was lucky, I found the cases Tig welded very well,and I was able to repair the shift drum too.
Unlike the mag alloy outer covers,they simply fall to bits when you get near them with the Tig torch...

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