Valve clearance advice needed

[morecowbell]

I'm doing the valve clearance check on my 2012 FJR, and I've hit an issue that I can't wrap my head around. Hopefully someone here can show me the error of my ways.

I'm familiar with the concepts of shim & bucket valves. I checked the valves on this bike 30K miles ago and no shims were changed. I checked the valves on my YZF-600 in 2018 and changed three shims to get the clearances into the middle of the spec range, and that bike is running beautifully...so I'd like to think I have an idea of what I'm doing. That is, until this time around on the FJR.

I found one intake valve at the tight limit, .15mm. Pulled the cam, found a 175 shim installed. I swapped that for a 170 shim and the new clearance measured .20mm, exactly what I calculated and expected. That's pretty close to the rest of the intake valves .18mm clearance. They were all surprisingly uniform.

Now for that one bitchy exhaust valve on the #2 cylinder. The clearance range is .18mm-.25mm; I measured the gap at .25mm. The rest were around .20mm-.23mm. I figured I'd swap that shim and get that clearance to .20mm like a few others. I pulled the cam, found that shim to be a 184...of course I rounded up to 185 as the manual says. So my brain says the gap is too big, needs to be smaller. Needs a thicker shim to close the gap. Sounds easy. I installed a Hot Cams 190 under the bucket, should bring the gap down to .20mm, if my brain is doing the math correctly (I was told there would be no math today). I installed the cam, rotated the crank a few times to seat everything, and then measured the gap...it showed .15mm! What the hell? From the loose limit to beyond the tight limit with a .05mm shim change. I thought the problem might be with the Hot Cams shim diameter being just a skosh off and not fitting properly into the recess on top of the valve. I ordered a Yamaha 190 shim from PartShark (delivered in 9 days, not too bad) and installed it this afternoon. Installed the cam, rotated the crank a few times...the gap still measures .15mm. I'm stumped. And frustrated. I briefly considered pouring gas on the bike and setting fire to it. But I don't really want to do that, because I really like riding it.

Does anyone have any suggestions as to what I could be doing wrong? I'm ready to pull the cam one more time and reinstall the 184 shim and just keep running the engine with that valve at the .25mm limit from here on out. At least the intake valve behaved like I hope it would, so I don't feel like a complete dumbass.

I appreciate any suggestions. Thanks!

[raYzerman]

I'd put the .184 shim back in and the clearance may measure .20mm. Perhaps an explanation is the engine was sitting, the valve wasn't fully seating for whatever reason. I usually check the clearances at least twice (two full sequences of rotating the engine) to determine the numbers. If they changed from the first time, I will check that particular one a third time, then decide what shims to change.
Feeler gauge checks are subjective too, and doing it more than once cuts that down somewhat.....
Wouldn't be the first time I pulled a cam more than once in a shim change either.... hate it but with all the valve checks we've done at tech days, I'd like to think we're a little smarter......

[N4HHE]

You suspected the new shims but did you measure the old shim? Is it really 0.184 or only marked 0.184? If you measured then is that shim flat? Try a 0.185 from the Hot Cams kit.

[FJRoss]

You suspected the new shims but did you measure the old shim? Is it really 0.184 or only marked 0.184? If you measured then is that shim flat? Try a 0.185 from the Hot Cams kit.

Agreed. I never assume that any shim is as marked. While a micrometer is preferred for best accuracy, I manage with a good digital caliper and good technique. Faster and easier.

[Road Runner]

I would agree with all the previous replies.
If you don't find the 184 was marked wrong, or rotating the engine and rechecking doesn't reveal anything, then just run it at .25mm. better to be on the loose side.
If the range is .18mm-.25mm, I would shoot for .23mm, because they get tighter as things wear, and setting on the loose side means longer service interval.
Also may want to run some Ring Free thru it before checking valves to make sure valves are clean and seated properly.

[raYzerman]

I use a micrometer and rarely have found old shims to be off much worth talking about.... but yes, I measure them just in case.

[Hppants]

Not on an FJR, but on a Versys 1000, I found a shim that was stamped, but the last digit was faded in one spot and it made a "4" look like a "8".

My coffee hasn't fully kicked in, but that might explain some of the delta, no?

I too measure them all with a dial caliper. For each shim to be changed, I measure what was in there, and then I measure what I want to put in there, and then I do the calculation of the anticipated new gap BEFORE i stick under the bucket. So far, I've gotten what I expected.

That S/S circulating that is supposed to help with this is TOO hard to understand. For me, it's just easier to to the math, one valve at a time.

[1911]

I would agree with all the previous replies.
If you don't find the 184 was marked wrong, or rotating the engine and rechecking doesn't reveal anything, then just run it at .25mm. better to be on the loose side.
If the range is .18mm-.25mm, I would shoot for .23mm, because they get tighter as things wear, and setting on the loose side means longer service interval.
Also may want to run some Ring Free thru it before checking valves to make sure valves are clean and seated properly.

+1 on the ring free. Before my last valve check I was pretty sure that I was going to be reshimming. 80k+ miles and at the previous check a couple valves were getting close to minimun lash. I used a dose of ring free and a ride around the neighborhood with a lot of right wrist to remove carbon and a whole lot of drive tire rubber

[raYzerman]

Nice.... no build-up on the intake stems, good to see. The intakes will carbon up first as they are much cooler than exhausts... pic of 90k engine ridden like grandma and RingFree was used very regularly........ hint, don't ride an FJR like grandma.
The (silvery) exhaust valves look reasonable, intakes are carboned up. This bike had low compression because the valves weren't sealing.....

[morecowbell]

Thanks for all the replies, I do appreciate it.

After having a night to sleep on it, I'm gonna go rotate the crank a few more times and measure the gap again just to make sure I was reading it right.

You suspected the new shims but did you measure the old shim? Is it really 0.184 or only marked 0.184? If you measured then is that shim flat? Try a 0.185 from the Hot Cams kit.

Actually, the markings were worn off the original shim, so I measured it at 1.84mm. I rounded up as the manual suggests. But since two different 190 shims didn't work, the idea of trying a Hot Cams 185 shim is genius. It should tighten the gap just a little bit, maybe to .24 or .23mm, which is inside the limit, but not so extreme as trying to close the gap to .20mm where I have failed miserably. I wish I would have thought of that. That will be my project for tomorrow; the independent shop with the Hot Cam kit is closed today.

I'll occasionally run a dose of Yamalube Engine Med RX through the tank. That stuff is labelled as a de-carboning agent for the top end, as well as corrosion protection from ethanol-blend fuels. I don't remember when I last ran any through the tank before this maintenance work, but it's a really good idea. I don't ride the bike like grandma, that's for sure...I put the spurs to it on a regular basis and occasionally ops-check the rev-limiter to make sure it still functions. But I guess it doesn't take much carbon to mess up the readings on a valve check.

Thanks guys!

[raYzerman]

I'd set it at .23 no problem, that's usually my target (70% of max), nominal or higher if I have to swap a shim. No problem at max either if you have to..

[N4HHE]

You suspected the new shims but did you measure the old shim? Is it really 0.184 or only marked 0.184? If you measured then is that shim flat? Try a 0.185 from the Hot Cams kit.

Agreed. I never assume that any shim is as marked. While a micrometer is preferred for best accuracy, I manage with a good digital caliper and good technique. Faster and easier.

Yes! While a high grade micrometer is desirable for accurate measure, accurate measure is not necessary for sanity checks. Dial calipers are great for sanity checks. Easy to compare two shims to know if they are approximately 0.005" different. Pretty darn reliable for verifying they are 0.010" different. Just how different? Who cares, if you find the next step shim then that is all you can do.

I spent years at a drafting table, and later on ECAD software, with a pretty good plastic dial caliper in hand. Collected datasheets for everything but often spent time with the component in hand with caliper to make sure things were as stated. And often to find the details not in the datasheet. And more time with enclosures getting holes in the right places for components on PCB to meet.

One day Harbor Freight had digital calipers for only $10 or so! Had to have one! Bought a bunch to give as Christmas presents to nieces, nephews, etc. Digital calipers sure are sexy but I prefer dial, no $@!%^ battery to replace every week or month (HF digital tools eat batteries). A generic metal dial caliper is my most trusted, but I'm still awfully happy with the plastic dial caliper. Maybe I'd change my mind if I had a Starrett or Mitutoyo digital.

[1911]

Somewhere around here I found out that Hayabusa? shims are available in smaller increments than OEM. .025mm versus .05mm IIRC.

I got my clearances right where I want them.

[wetwolf]

I just got done doing my 80000 mile valve check. 6 intakes too tight, 4 exhaust too tight.

Mitutoyu digital caliper, check, recheck. Borrowed the Hotcam shim pack from the indy guy here in town. I used up all his 170s, so I'm buying him a refill pack of those. So, .05mm is .002" and I do the math in my head. Leave 'em on the loose end and you will be good.

I'm hopin at 106000 all will be in spec.

[N4HHE]

Somewhere around here I found out that Hayabusa? shims are available in smaller increments than OEM. .025mm versus .05mm IIRC.

I got my clearances right where I want them.

IIRC some KTM dirtbikes and Harley-Davidson V-Rod use compatible 10mm shims. But H-D dealer MSRP was half KTM, came in half-sizes, parts counter was stocked and open 7 days/week, often staffed by smart young women in shorts.

[raYzerman]

Rocky Mountain ATV has Pro-X shims in .025 sizes for like $2 each.

[rbentnail]

Rocky Mountain ATV has Pro-X shims in .025 sizes for like $2 each.

Beat me to it! I've been using these for a lot of yrs. Every single one I've used measured dead on with the stamped value.

[morecowbell]

I just got done doing my 80000 mile valve check. 6 intakes too tight, 4 exhaust too tight.

Holy crap, that's a LOT of shims to change!

I got my FJR top end put back together this afternoon. N4HHE's suggestion of a Hot Cams 185 shim was the magic ticket. I wish I would have thought of that, but I was so mad/frustrated at the time, the easiest fix was beyond my level of reasoning. I measured it at 1.87mm and installed it. The valve gap ended up at .20mm, which is exactly what I was trying to achieve with the 190 shims. I guess that just shows that no matter how accurate you try to be in measuring or how closely you work the math, there's a lot of room for error. I pulled that cam out three times. That's way too much trial and error, but I'm glad to have the valves done. Of course I ran out of coolant this evening when putting things back together. I'll get more coolant tomorrow, synch the throttle bodies and it'll be ready to hit the road.

Thanks for the help!