First time valve adjust...what a pain!

[unclejemima]

I've never adjusted valves before, but I understand the basic principal and seen a few youtube vids.

I went to attempt this tonight on my 86 atc125M (vertical not horizontal motor) and what a PITA.

I had a set of flat feelers (first mistake) that I had to bend so I could even get it under the valve adjust bolt, and after i adjusted the valves, it clicks like a crazy...obviously to loose.

The problem may lye in where the proper TDC is. It was supposed to be on compression stroke, but I have no clue how to tell how.

I lined up the T mark on the flywheel, but how do I know when its on the compression stroke? One way the flywheel is loose, the other the flywheel is tight. What do I want?

Thanks!

[ailll1]

Remove the spark plug and put your thumb over the hole. Turn the engine slowly. You will feel air pushing on your thumb when it will be on the compression stroke

[Xpress]

Also, when on the compression stroke, the valves should not move one bit. Crank the engine over where you think it should be, and if the valves don't move, then you should be good.

[ATCrider42]

The proper prodcedure would be to locate the mark on the flywheel and then check the rocker arms for play. If you are at TTDC then there should be just a little wiggle in the rocker arms. If you are just at TDC then the rocker arms would be tight and you should turn the engine enough for the flywheel to make one more rotation til the mark comes around again, putting you at TTDC. Then make your adjustments from there. It's pretty easy once you do it a time or two.

[Xpress]

The proper prodcedure would be to locate the mark on the flywheel and then check the rocker arms for play. If you are at TTDC then there should be just a little wiggle in the rocker arms. If you are just at TDC then the rocker arms would be tight and you should turn the engine enough for the flywheel to make one more rotation til the mark comes around again, putting you at TTDC. Then make your adjustments from there. It's pretty easy once you do it a time or two.

Yeah, what he said :lol: :)

[Dirtcrasher]

The feeler gauges bent at the end work great.
I also chopped up a .003 thin which works well and does most Honda's.....

PS: The thumper Yamahas; You have to measure the slop, remove the 2 cams and bearings/clips, change the shim, measure the clearance again, change the shim again, time it and put it back together.

If you over-tighten the bearing caps, you ruin them.

As soon as there hard to start up warm, do the procedure again. It's money in the bank for repair shops.......

[Mr_RPM]

The feeler gauges bent at the end work great.
I also chopped up a .003 thin which works well and does most Honda's.....

PS: The thumper Yamahas; You have to measure the slop, remove the 2 cams and bearings/clips, change the shim, measure the clearance again, change the shim again, time it and put it back together.

If you over-tighten the bearing caps, you ruin them.

As soon as there hard to start up warm, do the procedure again. It's money in the bank for repair shops.......

alot of new thumper are like that. honda for 1 in their race machines

[tri again]

on overhead cam engines on cars, you can almost be assured of correct valve clearances with an exhaust gas analyzer (aka smog check), which can save disassembly of the cam towers pre and post valve lash spacer fiasco.

but that fact may have nothing to do with bike engine emissions.
unless the specs are accurate and actually mean something in the real world.

I guess that design saves on the number of moving parts.