Need help checking valves yz250f

[ZYtillIdie]

I want to make sure I'm getting the proper measurements for the valve clearances.

First I want to make sure I'm at tdc.

Also when sliding in the feelers, should I have to push em in hard or not?

For example, a .22mm will not fit between the lobe and bucket just barely sticking it in, but it'll slide easy if I just give it a little force.

Please help, my exhaust were way too loose but I lined up the fly wheel mark "I" with the notch and my exhaust were in spec. So I know tdc is crutial.

[ZYtillIdie]

[ubu]

So guessing by the .22 example, you are on the loose side of the exhaust valve spec. Being on the loose side isn't all that bad depending on whether or not the next feeler goes. TDC should be cam dots aligned with head and "I" mark aligned with notch. You look fine there. Try the next size feeler and if it doesn't go you should be good.

 

All I have is inch feelers, but I judge the force by going small to big. IE .005 easy, .006 hard, or .007 easy, .008 no

[ZYtillIdie]

So guessing by the .22 example, you are on the loose side of the exhaust valve spec. Being on the loose side isn't all that bad depending on whether or not the next feeler goes. TDC should be cam dots aligned with head and "I" mark aligned with notch. You look fine there. Try the next size feeler and if it doesn't go you should be good.

All I have is inch feelers, but I judge the force by going small to big. IE .005 easy, .006 hard, or .007 easy, .008 no

Alright thanks, but all 3 intakes I can't get the .10mm under them but with good force I can but that don't feel right to me. So my intakes are definitely too tight, which makes sense why my bike was hard to start.

[William1]

Do not over complicate things.

Spark plug out

Cam lobe faces completely away from the valve bucket. No need to 'check TDC'. Check the heel of the cam to the bucket.

Feeler gauge may take a little effort to slip in but on in, there should be little drag. Confirm by going one size thinner (no drag) and one size thicker (lots of drag) Understand it does not take a lot of pressure to depress a valve.

[ZYtillIdie]

Understand it does not take a lot of pressure to depress a valve.

This helps man, and I have that problem over complicating, just like to do stuff correct n precise. So basically you can shove a gauge in there that's too big but it's a false reading, you're looking for one that has some drag to it?

[William1]

This helps man, and I have that problem over complicating, just like to do stuff correct n precise. So basically you can shove a gauge in there that's too big but it's a false reading, you're looking for one that has some drag to it?

Yup.

Too small has no drag, too large, requires a fair bit of effort to get in and a lot of drag. After you play with the gauges a few times, it is a easy 'feel' to get. I rec. taking the blades out of the tool. I take three out, one small, one right, one too large. The tool with all the blades can be cumbersome and add to the difficulty in getting 'the feel'. Think Goldilocks.

[ZYtillIdie]

Yup.

Too small has no drag, too large, requires a fair bit of effort to get in and a lot of drag. After you play with the gauges a few times, it is a easy 'feel' to get. I rec. taking the blades out of the tool. I take three out, one small, one right, one too large. The tool with all the blades can be cumbersome and add to the difficulty in getting 'the feel'. Think Goldilocks.

Alright man explains why could get a .26mm in the exhaust when really .20 had some drag but I kept going up till I couldn't fit one under it period!

The intake no matter how hard I couldn't get the lowest .10mm under them.

So I thought, "hey maybe I'm not at tdc correct and I'm getting a false reading." So had to confirm with guys on here before proceeding. Hopefully should fix the hard starting I'm experiencing. Having to kick it 20 times cold start.

[William1]

Time to consider getting the valves done.

[ZYtillIdie]

Time to consider getting the valves done.

Brand new wiseco crank and cylinder kit, we're just installed. Guess my partner did the valves too tight. Exhaust is in spec Intake is tight. Edited November 12, 2015 by ZYtillIdie

[ZYtillIdie]

Big thanks to William

For stepping it up in this thread

[Jlash]

looking to get a feeler gauge set. my intake specs are .1-.15mm and .17-.22mm exhaust.. seems like most sets only have the .1 and .15 feelers.. id like to have one with something in between.. what are you dudes using?

[YZJohn250]

? is it better to be at the top of spec or the bottom? or does it not matter? Thanks

[William1]

? is it better to be at the top of spec or the bottom? or does it not matter? Thanks

Middle.

Some think if you run it on the tight side, you get more duration and the opening and closing of the valve is gentler.

Some think it can vary the cam timing slightly.

My own tests have shown basically none of these. Tighter seems to be slightly quieter.though.

 

The best part about running on the tight side is if you do have valve wear issues, you will discover it sooner though if you regularly check the valves, you'll discover it before the wear is a issue. I aim for the middle

[YZJohn250]

Thanks for the quick reply. I was able to get some oem shims and get more in the middle. With the .05 it was either at the top or bottom.