I have a 1984 Honda TRX 200. It was running fine until I decided to adjust the valves on it because it hadn't been done in forever. I consulted the owner's manual and followed the valve adjustment procedures step for step. I aligned the two timing marks to make sure that the engine was at the top of the compression stroke. Once I had the marks aligned, I then wiggled the rocker arms by hand and they were loose, which would mean that the engine was indeed at the top of the compression stroke. I then adjusted both the intake and exhaust valves to the specs recommended by the manual, which was .05mm(.002in). After I put the quad back together, it was difficult to crank. I did eventually get it cranked and it idled fine. It also runs fine at lower rpms, but at upper rpms it loses power and runs extremely rough! It spits a lot of white smoke out of the tailpipe when it is running. Also, the quad has a compression release lever, which is supposed to make it easier to pull crank. After the valve adjustment the compression release lever no longer works. The lever won't stick at the top like it is supposed to. Does anyone have any idea what could be wrong with it? I am out of ideas. Any help will be greatly appreciated! Thanks.

 

valves are to tight? try backing them off just a little

 

If I recall correctly, spec is .003?

Anyway, I'd repeat the adjustment, or at least double check.

Line up the TDC marks and check gap, then rotate it 180 back to TDC. You should have the rockers tight one way, and proper gap the other way (valves should be slightly open in overlap when TDC between exhaust and intake, and fully closed when TDC between compression and power stroke).

How big of an adjustment did you make when you did the valves?

 

I know where Jeffin is going!! As usual, good question dude!!!

 

I looked it up and it is .002
I would double check the valves like Jeffin advised.

 

How big of an adjustment did you make when you did the valves?[/quote]

JeffinTD, The adjustment I made was very slight. The valves were a bit too tight, so I loosened them just a bit. Based on your last post I am thinking that I may have incorrectly adjusted them on the exhaust stroke. Aligning the "T" mark is very difficult on this machine because it is hard to see and because the momentum of the crankshaft turning tends to make the "T" mark fly by the sight window very quickly. It is hard to rotate the motor from TDC Compression 180 degrees directly to the exhaust stroke because it takes me several rotations and some luck to get the "T" mark to line up. Any tricks to make this easier?

Also, could this be what is causing the compression release lever not to work? If I understand correctly, all a compression release lever does is hang a valve open during cranking...right?

I appreciate all of the help! This is my first valve adjustment so I'm sure I have a lot to learn.

 

I had the same problem with the crank flopping past the TDC mark once and what I did was put the plug back in just a few threads. This seemed to help. Air came out the threads but not like having the plug out so the suction kind of held the piston steady. Try that.

 

Pulling the plug so you aren't fighting compression pressure is a good idea.

Since you only made a small valve adjustment, I'm kind of doubtful that caused this big change in how the engine runs.

This is causing me to be suspicious that the problem is in the decompression lever.

I guess I'd still double check the valve gap- just because, then pull the cylinder head cover and see what's going on with the decompression system.

 

Thanks for all the advice everyone! I have been out of town on vacation for the last week, so I haven't got to put in much wrench time on the quad yet. I'm planning working on it this weekend though. I will keep you all posted on the results.