Adjusting valves ? Im a little worried

So i checked the valve clearances, if your sitting on the bike, the far right and far left checked within spec. The middle one did not pass so i pulled the cam, and the buckets. The far left had a 185 shim, the far right had a 186 shim and the middle had a 165 shim. I couldnt get any of my feelers to pass on the middle valve, i dropped down to a .02 and it still wouldnt pass. I swapped the shim for a 155 and still none of them would pass through. then down to a 145 and i could get a .07 to pass through but not the spec .10, now it has a 140 in it does this not seem a little drastic ???? or am i just being paranoid?

I have been having major major issues starting the bike. this is why i checked the valves.

Wow! That does sound crazy - but would coincide with the hard starting.

Have you tried the bike yet - is it starting easier now?

Even if it does start easy now, I would REALLY be tempted to pull the head and inspect - either your valve is worn beyond belief or the seat is gone.

Pulling the head will at least answer the mystery and possibly save you from spending thousands on a full rebuild.

Now there is one explanation that could be the issue - someone before you did the valves and replaced the middle one with a side one - the middle valve on these is shorter and carries a different part number.

Im going to go ahead and pull the head just to be safe, im wanting to use the bike as a street tard so i dont want her to blow on the interstate.

So i checked the valve clearances, if your sitting on the bike, the far right and far left checked within spec. The middle one did not pass so i pulled the cam, and the buckets. The far left had a 185 shim, the far right had a 186 shim and the middle had a 165 shim. I couldnt get any of my feelers to pass on the middle valve, i dropped down to a .02 and it still wouldnt pass. I swapped the shim for a 155 and still none of them would pass through. then down to a 145 and i could get a .07 to pass through but not the spec .10, now it has a 140 in it does this not seem a little drastic ???? or am i just being paranoid?

I have been having major major issues starting the bike. this is why i checked the valves.

was the middle intake valve zeroed?

Wow! That does sound crazy - but would coincide with the hard starting.

Have you tried the bike yet - is it starting easier now?

Even if it does start easy now, I would REALLY be tempted to pull the head and inspect - either your valve is worn beyond belief or the seat is gone.

Pulling the head will at least answer the mystery and possibly save you from spending thousands on a full rebuild.

Now there is one explanation that could be the issue - someone before you did the valves and replaced the middle one with a side one - the middle valve on these is shorter and carries a different part number.

hrmm i may have to look into this further.

was the middle intake valve zeroed?

Please explain zeroed.

Please explain zeroed.

it means that when you did the valve check there was zero gap between the cam and the bucket.

as I've been told that is the hint that its time for a valve job.

it means that when you did the valve check there was zero gap between the cam and the bucket.

as I've been told that is the hint that its time for a valve job.

Ah yes there was NO GAP between the cam and the bucket with the 165 shim, the 155 shim, and then the 145 shim i had to fight to get the .07 in there.

The center intake is shot. Any Titanium valve that:

> Needs more than a .10 correction to make spec., and/or

> will not hold at the clearance it was set to for an extended period (longer than 10 hours)

...has worn through its hard coating, and is a serious hazard to the engine.

The valves will look like this:

2in.jpg

Normal valves look like the one at the left here, with the one at right showing significant wear, and in need of replacement:

ex%20in.jpg

The center intake is shot. Any Titanium valve that:

> Needs more than a .10 correction to make spec., and/or

> will not hold at the clearance it was set to for an extended period (longer than 10 hours)

...has worn through its hard coating, and is a serious hazard to the engine.

The valves will look like this:

2in.jpg

Normal valves look like the one at the left here, with the one at right showing significant wear, and in need of replacement:

ex%20in.jpg

Gray if the valve was zeroed deosn't that also mean that the valve seat could be damaged and the seat will probably need attention?

thats what im afraid of i guess we will know for sure tonight guys! do i need to replace all 3 valves? or just the worn one? also where is the CHEAPEST place to buy an intake valve?

Gray if the valve was zeroed deosn't that also mean that the valve seat could be damaged and the seat will probably need attention?
The seats need attention whenever the valve is replaced, no matter what. They should be refinished, first by recutting the 30 & 60 degree angles to establish the width and diameter of the seat (and thus, where the contact on the valve face is), then by grinding the finished seat angle. The seats in YZ/WR engines are very durable, and rarely need much material removed, but they must be correctly finished in order to seal, and more importantly, so that the valve will last a reasonably long time.

At no time, under any circumstances whatever, should any coated titanium valve ever be lapped. Ever.

It's also important to check the guides. They also rarely wear much under normal conditions, but when a valve wears this badly, it can wear off center, which can put a side load on the bottom of the guide as the valve closes.

The seats need attention whenever the valve is replaced, no matter what. They should be refinished, first by recutting the 30 & 60 degree angles to establish the width and diameter of the seat (and thus, where the contact on the valve face is), then by grinding the finished seat angle. The seats in YZ/WR engines are very durable, and rarely need much material removed, but they must be correctly finished in order to seal, and more importantly, so that the valve will last a reasonably long time.

At no time, under any circumstances whatever, should any coated titanium valve ever be lapped. Ever.

It's also important to check the guides. They also rarely wear much under normal conditions, but when a valve wears this badly, it can wear off center, which can put a side load on the bottom of the guide as the valve closes.

thanks. would you just replace one valve or would you do the whole set?

thanks. would you just replace one valve or would you do the whole set?

is it recommended to replace it with a factory valve? or is the kibble white valves any good? also grayracer, where would you suggest having the work done for the seat angles? can a local shop do it? and if so what should i ask for a 3 angle valve job?

thanks. would you just replace one valve or would you do the whole set?
The trouble is, of course, that you have no idea how long it will be until the next one wears through. Always a tough call.
is it recommended to replace it with a factory valve? or is the kibble white valves any good? also grayracer, where would you suggest having the work done for the seat angles? can a local shop do it? and if so what should i ask for a 3 angle valve job?
I would use OEM valves. Stainless appeals to me on some levels, but I haven't really seen KW valves last much longer than OEM Ti valves. I have seen them fail early, too.

Precision is absolutely important in doing Ti valve jobs. Ask around at the local dealerships as to who does their head work. Then ask them how they do their valve seats, and how long their jobs hold up.

Being in Indiana, you aren't far from Michigan, where Ron Hamp Cycles is located. No one does better work than he does. There is also Millenium Technologies. Eric Gorr has a shop in that part of the country as well.

Any competent head machinist could do a proper job of it, but it depends on whether he has enough professional pride and integrity to actually do it.

The trouble is, of course, that you have no idea how long it will be until the next one wears through. Always a tough call.

I would use OEM valves. Stainless appeals to me on some levels, but I haven't really seen KW valves last much longer than OEM Ti valves. I have seen them fail early, too.

Precision is absolutely important in doing Ti valve jobs. Ask around at the local dealerships as to who does their head work. Then ask them how they do their valve seats, and how long their jobs hold up.

Being in Indiana, you aren't far from Michigan, where Ron Hamp Cycles is located. No one does better work than he does. There is also Millenium Technologies. Eric Gorr has a shop in that part of the country as well.

Any competent head machinist could do a proper job of it, but it depends on whether he has enough professional pride and integrity to actually do it.

Ok I believe i have found the problem. Shouldnt the middle valve be shorter than the side 2? If so then i have my found my problem. The middle valve i took out of the head is nearly new, and is the same length as the side 2 :ride:

Ok I believe i have found the problem. Shouldnt the middle valve be shorter than the side 2? If so then i have my found my problem. The middle valve i took out of the head is nearly new, and is the same length as the side 2 :ride:
Oops...

Yup, the center valve is supposed to be shorter. Who did that job? ;)

Uh oh that doesnt sound too good.

Oops...

Yup, the center valve is supposed to be shorter. Who did that job? :ride:

Gray do you have a rough idea how much shorter it should be? I should be able to look at the center valve and the outside valve and tell a difference right away right?

Sitting next to each other, there should be an obvious difference. In a 250F, it's about 6mm or so.

Ok here is the 3 intake valves tell me what you think. the valve that came out of the center is on the right its pretty much new.

ATT174940.jpg

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