I am having a problem with the T250. We cannot get the timing correct. The manual my shop has says the timing should be 2.88mm before TDC. The closest we can get it is .2mm BTDC. We checked all parts, replaced and gapped points and still cannot get it closer than .2mm. What are we missing?
The bike is a 71 T250 with a 73 GT250 engine installed.
Forgive me if this is either a dumb response or smartass-sounding, but is the shop manual for the '73 GT250 or the '71 T250?
For the T250
Sounds like the GT250 and T250 have some significant differences... I don't know about the timing spec, but according to this thread it looks like the GT250 uses two different points types while the T250 uses one...
I'm not really familiar with these bikes, but I am wondering whether it's a different timing spec between engines, a points mismatch, or as another post in that thread notes, it sounds like some aftermarket points don't have sufficient adjustment range in the slots...
I don't have a 250 in my book but gt380 (tripple) ranges from 2.05mm up to 2.93 dependant on sub model letter A thru K. the heads on those things must have crappy flame travel as most 2 storkes ar 1.8ish anymore your melting the crowns... BTDT....
Are you sure you have the proper points on the proper adjustment sub plate? there should be a L and R stamped in them? Behind the big plate theres a smaller Trig angle plate thats pined to the points cam. have theses two moved? Is the nut on the crank tight? can you turn the points cam with out moving the crank? it should ride on two bearings...
44
I have the bike at a classic bike shop and this is what they say about the timing:
Its either 2.88 mm BTDC or 24 degrees using a timing wheel (or you can use the timing marks on the rotor, but not as exact). The GT250 have left and right timing plate, different parts. The T250 should be the same. My points are the same for left and right.
Found the problem. The GT250 engine used a different right side point than teh T250 engine. The correct right side ignition point should solve the problem.
So were you able to time the left side okay?
I have it at a shop, but I don't think they had a problem with the left. I will know more tomorrow.
In reply to 44Dwarf:
Cannot time either side. Confirmed points are correct and the there is only one points cam which can fit and it has a key way so it cannot be installed out of phase. I have all kins of books which tell me how to gap points and how to inspect what the the timing is set at vs. what it should be, but none tell me what I should move to change the timing. I can install and remove the points. I can move them to adjust the gap, but how to I move the rotor or points to adjust when the plug fires?
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