What is this on exhaust cam?

Installed my mcct today and checked the valves also. What is this pin on the bottom right of the exhaust cam? I touched it with the feeler guage (hehe) and it is pretty loose and moves around.



Also my intake were at .152mm but my exhaust were different. The left was at .229mm and right was .203mm Arent both supposed to be the same?

The bike is a 07 sm with 5,400 miles.

that is the decompression actuating pin. It is supposed to be able to turn easily and usually rattles a bit. The intake clearance is right on, the exhaust seems large to me, but as they wear, they tighten, I guess it's good-do a search for valve clearance/lash-I have hotcams and use the card that came with them for clearances-.15mm in., .18mm ex. if I remember right.

Decompression mechanism, makes starting easier

Thanks for the quick replies. That was what I was thinking just wanted to make sure. It seemed out of place for it to be loose like that and looked like it had some wear on it. Yeah the mcct wasn't too bad. Had trouble getting the old gasket off and not sure if I over tightened it, hope not. Might be a little too tight but that's not a big deal right?

Your valve clearance is in spec, intake is right in the middle of the tolerance, and exhaust is near the tighter end of its tolerance.

Stock cams should be

In .10mm -.20mm

Ex .20 -.30mm

Thanks Wog. Hey what kind of setup do you have on your 434 sm?

the auto decomp is your best friend in regard to easy starting

the auto decomp could be your worst enemy if it fails and takes out your motor due to wear .

Well how loose is it suppose to be? Cause it is pretty loose. I would say it is like a loose tooth that's about to fall out. Moves a little in all directions.

Thanks Wog. Hey what kind of setup do you have on your 434 sm?

Motor is:

Cylinder works +4mm Big Bore


Single layer base gasket

Trailtech light flywheel

39mm FCR/MX carb


K&N air filter

That's exactly where I want to take mine. Already have exhaust and k&n now I just need the sm fairy to bring me the rest haha. Did you do any valve Work/do you have to do valve work with those cams?

I haven't done any work on the head yet. The motor only had 2000kms on it when I tore it apart so I left the valves alone. Next winter I will probably do the valves and springs, and probably a stroker crank.

But for now the bike runs great.

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