Questions about timing/valve clearance
 

I am trying to measure my clearance for the first time, and I have some questions.

First of all, when you put, say cyl. #1 to top dead center compression, do you measure the intake AND exhaust of cyl. #1.

And when you have cyl. #1 at TDCC, you can measure Cyl. #3 as well, right? And the same with 2 and 4?

But most importantly, I am not even sure I am finding TDCC correctly- I watch the intake lobes of my selected cylinder as I crank the engine. After the lobes let off the bucket (let the bucket raise back up), I then watch the two sprockets and wait for the marks to line up as I continue turning the engine over slowly. The next time the marks line up after the intake closes is TDCC. Right? I only took off the little peep hole from the pulsar cover, so I havent used any marks inside there. Are those the marks I should be using, or am I doing it correctly?

If I am doing it correctly, then some of my exhaust clearances are out of spec by ~.004mm. Could this be a cause of backfiring?

Thanks for any help.

this should help:

http://www.bayarearidersforum.com/fo...ad.php?t=85499

Ahhh. That cleared up my questions perfectly. Thanks. But at the same time it sort of confuses me with a different question.

Why do you measure the intake on cyl #s 1 and 3, but read exhaust on cyl #s 1 and 2 with the engine still in the same position? Is the firing order 1, 3, 2, 4?

Also, if one were to need a shim adjustment, does one have to buy a whole kit for just a couple shims? Are these shims interchangeable with other bikes?

Thanks again

1-2-4-3

Sounds complex. I just turned the crank until I saw the cams were not opening the valves. Don't make it more complicated then it needs to be.

Not sure about the shims, sorry.

You can by the shims singly i know wemoto sell them for about £3.50 each and you can also swap and change the old ones around.

Ok, I know I was running warmer than usual last summer, but is it bad if I look in my exhaust ports and my valves are white? Am I going to have to take the top end off to know for sure? I'm worried.

thanks for the help.

I wasn't sure if the cam were perfectly round except for the lobes. I thought maybe some were different, but if all you have to do is measure clearance while the lobes are facing up, then I think I did it correctly.

Yeah, when the valve is shut on the round part of the cam, its shut completely until it hits the lobe again.

I missed your backfiring question, and I would have to say no. .004 is very barely out of spec. It calls for what.. .19-.25 and you are at .254? no biggy. Backfiring is most likely due to leaned out jets or an air leak.

And another question I missed, yes this is bad, you are running lean. They should be light brown, not white.