Anyone else have a problem with the cam mod?

[Sweendogie]

ok when i first bought my quad it had the cam mod done to it and it wouldnt start up right especially when it got hot... so anyways i set it back to stock timing and it ran perfect no problems at all and it started right up.... i had a shop adjust my valves and when they set the timing they did the cam mod for me... now once again it wont run right and wont start up worth a crap but when it does start up it doesnt really seem like anything is wrong... anyone else hear of anyone having this problem? its really pissing me off.... oh its a 2007 yfz

[daddio]

You need to have the lash a little on the tight side on the left exhaust valve, when doing the cam mod.

[Ryan]

Originally posted by daddio
You need to have the lash a little on the tight side on the left exhaust valve, when doing the cam mod.

Can you explain this a little better?

I do have a similar problem... Mine runs great with the cam mod done, it just starts a little ruff. but it doesn't like to start cold without the choke, and it doesn't always start in gear with the clutch in.

[daddio]

By making the valve lash on the left exh valve a little tight, the decompression mechanism will open the valve a little further and for a little longer.

On my high compression motor, 1 shim size made the difference between the motor not turning over at all (all the way) and starting. 1 shim size bigger and it started way easier. I origionally set my valve lash on the "loose" side, thinking that as the valves stretch, and the seat gets worn, the lash will get tighter, thus prolonging the time between valve adjustments.

Boy was I wrong.

[Sweendogie]

Originally posted by Ryan
Can you explain this a little better?

I do have a similar problem... Mine runs great with the cam mod done, it just starts a little ruff. but it doesn't like to start cold without the choke, and it doesn't always start in gear with the clutch in.

thats my problem exactly... doesnt want to start cold unless its half choked...