New TRX70 and questions

[Tomcall]

Just picked up this 86 trx70 today. New project for me. Can anyone tell me if the 73 and 74 atc70 engine parts are interchangeable with the trx70?
Thanks

[jb2wheels]

Yes - all ATC 70 engines will bolt in.

You'll need the ATC coil too.

The TRX engines use CDI instead of points.

[Tomcall]

Thanks jb2wheels
I was needing to know if the engine parts are interchangeable. I have a number of parts for a 73/74 atc70 motor. Are the internal parts identical to swap out if I have a part in better condition from my 73/74 atc70 parts?

[jb2wheels]

Ah - got it!

Crank is different due to CDI flywheel and such.
TRX has a 4 speed instead of 3.

Top ends should swap.

I put an 88 kit from DRATV on my 86 TRX. As I recall, it was listed for all ATC/TRX 70s.

[Tomcall]

Thats helps. I was thinking the bottom end was likely different. I refreshed the clutch and it looks identical to the other atc's.