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Old 11-30-2012, 05:53 AM   #39
Beastly Adventurer
Joined: Jan 2010
Location: Grand Valley, Colorado
Oddometer: 4,874
Originally Posted by CaliKarl View Post
Okay. So why then not keep the clearances loose in the first place? So that they're ringing the dinner bell?
It does not make any sense. The other bikes I have all have their valves in the .08-0.22 on the intake side, and 0.18-0.32 on the exhaust side. The next biggest bike is my 55 RWHP Suzuki DRZ 470. A full flood race build motor with just about twice the output as compared to stock. it runs 0.10-0.20 intake, and 0.20-0.30 exhaust. The 8GS changed in two ways. space is moved up, and margin was increased from 0.08 to 0.11 ( exhaust). That margin is pretty standard, as the other bikes I have are 0.10. But as to determine why BMW did this.... My guess is some idiot thought this would be a good thing. That's it. They have prided them self that these valves do not move, thus it is unnecessary to increase the spec's. Mind you as abrasive air is ingested through normal operation ( slightly increased with guaze filters like K&N) over time the valve seat will wear, and the valves will now sit a little higher in their seat, thus decreasing the clearance between shim, and the valve rod. But to increase the tolerances like this is sort of like giving your Yugo a rear defroster to keep your hands warm, when you push it..... except our BMW does not break down like the Yugo.....wait... What did I just say.... IMHO... The old valve specs are plenty. You most likely will not hear any difference in the sound if you change to the new spec's. You would just be wasting your time. This is my opinion only. If this bike had a tendency to move valves... I'd say great, change the spec's to facilitate this, but it does not. Don't sweat it, and just check'em at next scheduled time.

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