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FFRNDAN
09-11-2023, 01:52 AM
I've swapped an engine from a derelict 84-85 (cant remember the year) atc125m into a 1968 honda ct90 frame as a "resto-mod" project.

The motor I got had the exhaust port damaged so I bought a new head off marketplace a swapped it on.

I've got it back together but it won't run. I suspect I've gotten the cam timing off somehow.

-Motor set to "T" mark on flywheel in the little window.

-Cam is set in so once bolted in, the timing advance lines up with the line on the CDI pickup ring.

-Valve clearance set.

-I have spark, fuel, and compression, but it won't fire, even with a puff of ether.

Please someone help before I toss it all in the corner. Thanks.

MrConcdid
09-11-2023, 09:20 AM
I am no expert on those horizontal engines, what's your compression reading? are you sure the cam is in correct, there have been reference marks on the head at 9'oclock and at 12'clock, the cam lobes should point towards the piston at TDC which means there is no pressure on the valves. go back to the basics, due not assume anything. triple check your compression first it must be 95 psi or better, then check your cam position and timing marks, you should find your problem.
I hope that helps, these are not my favorite engines sorry.
MrcBuilds