Fourtrax 70 Timing

[williams]

I split the case on a 1986 Honda Fourtrax 70 and repaired a shift fork. I have reassembled engine and ATV and was confused with the manuals instructions on timing. SO HERE IS WHAT I GOT....... The engine is 70cc and it has a magneto type cdi ignition. NO POINTS, and you cant adjust the timing in any way unless I guess you move your chain position on the cam or fly wheel position The directins were confusing so I went with these timing marks......... there is a T and a F and ^ mark on the magneto. There is a mark on the crankcase when cover is removed (when cover is on you remove a plug and use its time mark to set timing , but this plug and mark are in a different location than the mark on the case itself,,,,,,which one?) Also which mark F or T or ^ on what mark for this magneto with cdi box? At TDC I put the T on crankcase mark (this put the F in the plug window mark) and the magnet was just about to cross over the pulse generator. Next I turned cam so both valves had freeplay, installed my cam sprcket with the O mark matching the mark on the head and put on the chain. CRANKED up second pull and idled better than before but it doesnt have power in gears beyond 1st. I mean it want pull me and it should. Is this timing set correctly? Rebuilt top end 3months ago. Help please........ By the way gears shift great........Thanxxxxxxx Sorry so long of post

[Snafoow]

Hmm, If you don’t know if its right then I would say it is not. The cam timing not being set right will cause low power but it will start and idle. You run the risk of valve and piston damage also.

Sounds like you almost got it right . Yes, you use the “T” mark on the crank or magneto. After you line the marks up, install the chain and set the tentioner, you need to turn the crank 720 degrees (2 complete turns ) engine rotation (same way crank turns when engine is running) to make sure both cam and crank marks line up again to ensure it is in time. I am thinking you may have missed it by 1 tooth.



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