Unfamiliar Valve Shim

Hey everyone! I am working on checking the valve clearances on my 83' XJ750. So far, I have gotten through checking all clearances and now I am through pulling and documenting 3 of the shims. The 3rd on I did (Intake #2) had a weird number on it. I have not been able to find a thread that showed a similar shim. This one does not start with Y like the others do. Has anyone seen anything like this? To me, this looks like it says "2715".

 

You'll need to measure the thickness with a pair of calipers or a micrometer to establish what the actual size is............

 

I measured it and it came out to 2.715mm. Pulled another one out and it was labeled 2.875. Measured that one too and it was very close to what it was labeled as .
These aren't labeled in the chart - any way that I can find out what shim sizes I need?

 

These are Kawasaki from my KLR
Same size as the XJ obviously don’t have the Y in front. I think BMW use same size also and I think they go 4 digits just to be special.
If these shims are too tight now then you’re looking for the next size smaller XJ shim, maybe 2 sizes smaller, you didn’t mention your clearance

 

Clearances and shim sizes are as follows:

EX1: 0.13mm - y270
EX2: 0.13mm - 2.715
EX3: 0.15mm - y270
EX4: 0.06mm - 2.875

IN1: 0.13mm - y280
IN2: 0.06mm - 2.875
IN3: 0.08mm - 2.825
IN4: 0.05mm - y290

Does the math work out like this?
New Shim = Current Shim - (Ideal Clearance - Current Clearance)

So for Inlet 2:
New Shim = 2.875 - (0.13mm - 0.06mm) = 2.805?
Assuming that I should be aiming for the middle of the tolerance. I have seen replies in threads that say you shouldn't aim for the middle, but haven't found if you should aim for upper end or lower end of the tolerance.

 

So bigger problem. I got some new shims from the dealer. Looks like one of the shims might be too big for the bucket. It looked like it fit well when I dropped it in there, but when I turned the motor over to get my tool out, the shim jumped out of the bucket and is now sitting on top of the bucket. I am having a hell of a time getting it out. Any way that I can push the bucket down to get clearance to remove the shim or do I have to take the cam shaft out? If so, any threads that explain how to do this? I am afraid of turning the motor over too far and breaking something since the shim comes out and is pushed around by the cam lobe. Did the dealer give me a shim that is oversized? I would have to measure when I get it out, but assuming that it was seated in the front, but was not fully seated in the back, where I couldn't see too well because of the tool. Any advice would be greatly appreciated.

 

They can be a tight fit on top of the bucket.
I agree with you it probably wasn’t fully seated.
I just wrecked a 650 motor and the shims were all difficult to remove, real tight fit
Removing a camshaft will require rotating the motor but if you just slacken the tensioner and remove the cam caps it will make more room to get that shim out

 

Simmy, you're a genius. I did exactly that. Got the shim out. Measured out to be 29.5mm in diameter. Took it back to the dealer and had a long conversation. I said they didn't fit. Parts guy said they should. And we went back and forth like that for a while lol. Went home and ground it down as close to size to another one I had. Fit right in after a couple revisits.

Posting my shim size and clearance chart if anyone cares to reference this.

Since I had to take the carbs off to get to the tensioner bolt, going to revisit those and do a bench sync. After that, put those bad boys back on, compression test, running sync with carbtune, air fuel mixture with colortune, and replace the rubber brake lines with some steel braided lines.

Hoping to get her running right!

 

29.5mm shims are Suzuki shims, won't fit (Yamaha shims for these models are 29mm), parts guy is clueless, grinding the OD might work but is sketchy, I would recommend getting the proper 29mm OD shim. The last thing you want to have happen is have a shim spit out of the bucket at 9,000+ rpm's...................

 

Good point Chacal. As much as I trust my machining skills, I got a new 280 shim that fits. Got it together and synced and runs way better than before.

3 things though.
1. A lot of vibration in the handle bars and foot pegs in every gear from 4500 to 5500 RPM. It's not like a death wobble, but more like a vibration from your phone. Except stronger. Way stronger. Not sure if this is normal for these bikes.
2. Still a high idle after the motor gets hot. Idling at 1100-1200 RPM when it warms up, but after a 1o-20 minute ride, idle climbs to 2800-3000 RPM. Should I adjust the idle after a 10-20 minute ride?
3. Still have a lot of smoke coming from the motor at red lights or when I park it. At this point I have probably burned off all of the oil that might have spilled during maintenance. Noticed that some also comes from beneath the engine where the two parts of the exhaust meet. Probably not steam from condensation 10-20 minutes into a ride. Any thoughts on this?