Rocker arm tappets not sitting flat on valves
 

I was adjusting the valve clearence on my bike because they seemed to be too tight when I noticed that the rocker arm tappets didn't sit flat against the tip of the valves, Is this normal? The bike has only 10k miles.

Attachment 24652
Attachment 24653

It's exactly the same on both of my Hawks and Magician. I haven't had any problems caused by it though and since all 3 were that way I haven't worried about it to much.

Not sure if this is helpful but I hope so.

Yes, that's normal and if you imagine the rocker arm pushing the valve down the point where they meet will become more flat, if that makes sense. Because of the arc of travel.


Oh, and my hawk looks exactly like that too :-)

My Brozz and Fathers Hawk look exactly the same.

Does anyone by any chance know the size of the locknut and the square of the adjustment screw? I believe the locknut was 10mm but have no idea the size of the square.

I am trying to order a valve adjustment tool but I am not sure what size I need and I am trying to avoid removing the cover again until the next adjustment, but I would like to have the tool by then.

I have adjusted my valves twice and each time it was a major PITA... I felt like for the life of me I could not get it to lock down at the right gap. I would get it perfect then tighten it down and it would be too tight. Finally I went up a size to .08mm and when I tightened it, the gap was correct at .07mm on the gauge. After the engine break in I will readjust them to .05mm

The size of that adjustment square on my ZongShen Sierra would fit in a size #2 square drive screw, and in fact using one of those was one way to build such an adjustment tool.



http://i442.photobucket.com/albums/q...tenance135.jpg


TBQH I didn't have any such screws laying around when I did the adjustment, nor the specialized Yamaha tool, I simply used some pliers to turn the square and tried to tighten the nut without moving stuff too much.


It worked, but the downside was that I had to re-check the tolerances several times, as tightening the nut would somehow throw them off (looser) after another couple cranckshaft revolutions.

Yep, normal. Two flat surfaces, one travels in an arc, the other in a linear fashion at an angle to the arc. The adjuster sweeps down and in, so at a certain point the two faces will be in full contact, and as it keeps sweeping the other edge will then be the only contact point.

[QUOTE=ChillRider;360407]The size of that adjustment square on my ZongShen Sierra would fit in a size #2 square drive screw, and in fact using one of those was one way to build such an adjustment tool.


Great idea! :tup:

take a picture with the valve fully open, same but reversed.

Brilliant! I will give it a try in about 75 more miles :)

ya I might have to give that a go myself...handy and I might already have the parts laying around.

Thanks for your advice, I adjusted the clearence with 0.05mm intake and 0.08mm exhaust and now it seems to run fine :)

ChillRider - that is an absolutely awesome idea!!! :tup: Does the screw in the wire nut loosen up when you twist it? If it does, I think adding some gorilla glue to the wire nut would hold the screw in place.

10k miles!