Checking Valves and Feeler Gauge Question

[woods-rider]

I checked my valves last night and they all appear to be a bit tight, but the feeler gauge I have doesn't have nice round numbers on it and the increments seem kind of large to me. On the intake side I could fit the 0.076mm but not the 0.102mm which is the next size up. Spec is 0.10mm-0.15mm. On the exhaust side I could fit the 0.176mm but not the 0.203mm which is the next size up. Spec is 0.20mm-0.25mm. Do most feeler gauges have smaller increments between them so you can get a more accurate reading or is this normal and people just split the difference between the one that fit and the one that didn't?

Also, while I have you attention, I read that you are supposed to use assembly lube when putting the cams etc. back in. What exactly is assembly lube?

Thanks in advance for the help.

[woods-rider]

Another question that I did a quick search for, but couldn't find the answer:

Do all WR450s of a certain year come stock with the same size valve shims or are they put in at the dealer on an as needed basis when they build them? Basically, I bought my bike new so is there a way of knowing what size my shims are without taking them out first?

[Flagstaff]

You're on the tight side, and for reliability you're better to be on the loose side. It's allways a little tough using American guages for metric measurements. First time you have to read shim size off shim and measure to confirm. Keep track of what you have in there and in the future you can just do the math. problem is, access is tight, it's hard to get a good reading. Unusual for clearance to change much, and all five tight?

[Flagstaff]

Assembly lube is a cheaplube to provide lubrication during startup, before the oil get's circulating. Always used it on street bike rebuilds, but just occured to me didn't use on my WR assembly. These are tough bikes, I get a little sloppy on the details.

[woods-rider]

Yeah, all 5 are tight. His is the first valve adjustment this bike has EVER needed in 5 years of hard miles and I am more than happy to give my girl some attention she deserves. So do I just split the defference between the feeler that fit and the one that didn't to come up with my clearance number used to calculate what new shims I need?

I'll have to pick up some assembly lube when I get shims on Tuesday (bike shops around here aren't open on Mondays).

[SXP]

Yeah, all 5 are tight. His is the first valve adjustment this bike has EVER needed in 5 years of hard miles and I am more than happy to give my girl some attention she deserves. So do I just split the defference between the feeler that fit and the one that didn't to come up with my clearance number used to calculate what new shims I need?

I'll have to pick up some assembly lube when I get shims on Tuesday (bike shops around here aren't open on Mondays).

Looking at the numbers in your first post, it looks like if you went down one size on each shim (0.05 mm thinner), that would put you in the tolerance window for each valve. For example, if one of the shims you pull is a 175 (1.75 mm), then a 170 (1.70 mm) shim would put you back in spec. New shims are sold in increments of 0.05 mm (160 (1.60 mm), 165 (1.65 mm), 170 (1.70 mm) etc.). The fly in the ointment here is that the factory shims are often not multiples of 5, i.e., you could have 178, 163, 182, etc. size shims. You'll only know once you have them all out. There's a good chance you'll be able to shuffle some of the shims around so you won't have to buy five new ones.

Don't forget to use an inch-pound (NOT a ft-lb) torque wrench on the cam cap bolts, and then too, lower the torque to 75 in-lb instead of the 86 in-lb.

Good luck with your valve adjustment:thumbsup:

[WR450FGreg]

.

woods-rider,

PM sent.

Greg

[Flagstaff]

Agree with SXP.

[bg10459]

OEM Honda shims are the same and come in .025 mm increments....ususally cheaper, too.

[woods-rider]

thanks for the info guys. Honda shims sound like a good way to go to get a finer tune.

I got my shims out today and all the intake numbers are easy to read (182, 184, and 184), but the exhaust numbers are basically gone. I measured with my calipers though and got 178 for both. I think I am going to to down to a 175 and two 180s on the intake side. I am undecided on the exhaust side though between 175s or 170s. Any recommendations? The clearance on all the intakes were .076mm-.102mm and all exhausts were .178mm-.203mm.

I will pick up the shims Tuesday because the shops here are closed today and tomorrow.

[SXP]

OEM Honda shims are the same and come in .025 mm increments....ususally cheaper, too.

Nice to know, thank you:thumbsup:

[C-P]

Don't forget to use an inch-pound (NOT a ft-lb) torque wrench on the cam cap bolts, and then too, lower the torque to 75 in-lb instead of the 86 in-lb.

Good luck with your valve adjustment:thumbsup:

Did Yamaha (or common knowledge) reduce the torque specs for the cam cap bolts? Just curious as I've got my next valve check coming up...thanks!

[SXP]

Did Yamaha (or common knowledge) reduce the torque specs for the cam cap bolts? Just curious as I've got my next valve check coming up...thanks!

More of a shared knowledge thing from such experienced hands as the YZ forum moderator (greyracer), and many others. It's the torque value I've been using for many years since being advised of it, with absolutely no issues.

[matt4x4]

The Factory shims the valves as close to the tight end of spec as they can - it adds to the longevity of the components to have LESS clearance (but within spec) between the cam and cap.

As for assembly lube on the cams, just use the same oil you run in the bike, I lube everything with that, basically, you just don't want it to be dry on any bearing surface because it takes a few seconds for oil to pump through everything and reach the top end.

[woods-rider]

Oil, gotcha, that's one less thing I need to buy now.

Once your valves start to move do they typically keep moving and need to be replaced relatively soon (within the next 50 hours or so?) or can I expect another 5 years before my next adjustment (not valve check obviously)?

[02WR426Cali]

With the Titanium valves once they get tight they will get tight again more often. No telling the exact number of hours but you should check more often after the first adjustment. I think the general rule is usually 3 adjustments max before you get some new valves.

Also you should buy some new feeler gauges that have the correnct numbers to make things easier. My set has .10mm .13mm .15mm .20mm .23mm .25mm etc.

Makes it very easy with increments like this.

[woods-rider]

Man, a feeler gauge like that would have been handy. I'll definitely get one before I check them again.

[woods-rider]

After a little more thought and now knowing I should try to stay away from the extreme end of the loose side of the spec here's what I think I will do. Please let me know if this sounds good or not.

Intake:

Existing shims: 1.820___1.840___1.840

__Clearance*: 0.089___0.089___0.089

____Target**: 0.130___0.130___0.130

____New shim: 1.775__1.800___1.800

___New Clear: 0.134___0.129___0.129

Exhaust Shims:

Existing shims: 1.780___1.78

__Clearance*: 0.191___0.191

____Target**: 0.230___0.230

____New shim: 1.750___1.750

___New Clear: 0.221___0.221

* clearance determined by averaging the largest gauge that didn't fit and the smallest gauge that did fit. My gauges have increments of .025 mm so by averaging I could be off by as much as .0125 mm.

** The spec clearances for my bike are .10 mm -.15 mm for intake and .20 mm - .25 mm for the exhaust. How do my target clearances look? Should I be aiming tighter or looser?

[woods-rider]

Anyone want to comment before I head out to buy these on my lunch?

[bg10459]

Should I be aiming tighter or looser?

I didn't scrutinize your clearances, but in general, you would want to go on the loose side of the spec because the valve clearance will tend to get tighter. That said, the valves on these bikes are so good that you probably won't need another adjustment after this, so you might be OK to go with middle to tighter end of the spec. Really, you'll be OK as long as you're in the range.