Have a 1972 tf. 125cc need piston and rings carnt seem to find any so would a newer model tf engine fit in the 1972 frame. If so what year model tf engine would fit best thanks
The cost of the engine would probably cost you almost as much as you would have to pay for a replacement bike. You are talking about a 42 year-old motorcycle. Parts are extremely rare, even used. Plus, if you have to replace the piston and rings, you should really have the cylinder taken to a shop that does boring work to have the cylinder walls checked for elongation and uneven wear, These are measures in thousandths of an inch, so you cannot be sure checking "by Mark I eyeball", You cannot know for sure unless unless you are using a bore gauge of the proper size an a micrometer to calibrate the dial gauge of the bore gauge. I am 65, so I remember when those bikes were new. The tf models were changed quite a bit over their production runs, and unless you happen to run across a mechanic who has done engine swaps on that particular model with another model year you are going to have to experiment, and that might become expensive. You might have to try several different models before you got one that fit, You are obviously not a collector, because an older bike become instantly non-collectable after that kind of engine swap. If you are not a collector of antique motorcycles, give it a decent disposal, and spring for something newer. As I said, the engine is the most valuable part of the bike. If you absolutely need to keep that frame, you will probably have to buy the complete bike, because you will probably have to grind off some motor mounts and weld on those from the newer bike, whose frame you would have to cut apart to be able to grind the remaining frame off the new motor mounts. You are talking about many months and much money to find a suitable donor bike, and then about another month or so to first measure the exact height in the frame your old engine fit, then cannibalize two or three bikes to get the right assortment of mounts to fit another motor. Then you will need to get inventive about the exhaust system, because the exhaust port and the frame mount for the exhaust may not match. More experimenting and measuring. You will need to know quite a bit about pressure waves and sound reflection before you adapt bits and pieces together to make a new exhaust system. Sorry to run on and on, but that is what will happen if you try to play mix and match with any Japanese motorcycle. They made so many changes from year to year that the factory could not even tell you what model engine would fit, not with certainty. Even if the people who worked on that motorcycle were all between 20 and 30, they would be 62 to 72 years old by now. I would suggest you just either give it up as a lost cause, or store it properly (disassembled, parts cleaned and then coated liberally with clean grease) and hope you run across a 1972 tf 125 with a good motor and a bet frame. Stranger things have happened. But not many. I know how hard it is to let an old warhorse go, but I think you will have to. Sorry, but I am retired too, and it even happens to motorcycles.
Oct 30, 2013 |