Valves not fully closed at LT mark

S

silverheli2000

Active Member
HI All,

As the subject says, I've been having running issues with my bike (history below) that I believe was related to the valves not being adjusted properly. I get the covers off (side and valve), and follow the steps looking for TDC by letting the left valve go all the way down, then start to come back up....as soon as it started to come back up I aligned the LT mark with the notch on the engine. I should have TDC and the valve should be fully closed, but its not. The valve doesn't fully close until several inches past the LT mark. I have the valve adjusted out as far as possible, and I have NO play until several inches past the LT mark where I have lots (because its fully adjusted out). Any assistance would be greatly appreciated.

History:

Engine was sourced from CL as the bike's original engine was knocking real bad. The owner didn't have much info other than the engine was being saved for another project that never happened. The engine had both recall marks on the vin plate, so I took that to be a positive as the one I had did not. I swapped engines myself and was able to get everything up and running and it ran pretty strong, but very shortly it quickly started backfiring on the right side as well as fouling both plugs quickly.

Thats about all the back history I have...and I appreciate any and all guidance you may have.

Thanks in advance.

Chris from Indiana.
 
The valve is only going to be closed at TDC every other rotation.

The valves are closed at the end of the compression stroke / beginning of power stroke, but at the end of exhaust stroke / beginning of intake stroke the valves will be open.

Try turning the crank another 360° and see how it goes.
 
Thank you Sonreir, I really appreciate your reply.

I'll be honest, I did not know that...

Still fairly green and possibly rely on manuals a little more than most for my "how to" guide. For what its worth I did search a bit on here but was unable to find a good reference to my issue, which is why I made a new post.

I will report back and hopefully the oversight that I'm on the wrong stroke is the issue.

Thanks again.
 
Maybe this helps a bit...

4-stroke-engine.gif


At the end of four and beginning of one, both valves are actually open at the same time. End of two and beginning of three is when both valves will be closed.
 
2 top dead centers. One exhaust, one compression. You want compression.

While rotating the engine, watch for the intake rocker to begin going down, then come back up, when the rocker stops coming back up, start watching the timing marks again, line them up, and you are at top dead center compression.
 
Just a quick reply...of course you guys were right, 180 degree turn and they were closed properly. Reading the manual too closely and not thinking of the actual action of the engine will be my excuse. Thanks for the help and sorry for the pretty obvious post...
 
Finishing this thread out...Started up the bike tonight and it runs as strong as it has since I've had it. the right side was backfiring pretty badly and both plugs were fouling. I thought for sure I lashed the valves which is why I didnt try it again until now...obviously I was doing it incorrectly. The right side had absolutely zero play at all when fully closed...the left had very very very small amount of play, not anything near the tolerances in the book. Appreciate the quick obvious help.
 
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