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Old Yesterday, 09:58 PM   #1
SByota OP
Joined: Nov 2013
Location: Ventura, CA
Oddometer: 13
2005 Yamaha R1 valves

I just got the valve cover off my newly acquired 2005 R1 and checked the valve clearances. I have checked/adjusted the valves on several different moto’s (CBR 600, FZ1, YZ426) and have never seen this situation before. The center intake valve measured at .37mm, WAY bigger than the spec (.11-.20mm). All the other intake valves were .15mm and all the exhausts were at .23mm.

I pulled the intake cam and it looks great. I measured the cam lobes and it also measured all to spec. The bucket and valve tip looked fine and the shim I pulled out was a Yamaha 2.00 mm. I replaced it with a 2.20mm to bring the valve clearance back into spec. I ran out of time to measure it with the new shim, but I have no doubt it will be good. I also looked down into the intake and the valve/seat didn’t look any different than the other intake valves.

I must have spun the engine around 10 times and rechecked that intake valve over and over again. It measured the same every time. I have never seen a valve that out of spec in the “wrong” direction. I know that the valves/valve seat generally wear in the valve seat area and the clearance gets smaller over time.

Has anyone seen anything like this? Is there something I might be missing? The bike has 13.5K miles and an unknown service history. I wasn’t been able to ride it, but it started up fine, idled good, and revved freely with no strange noises. The bike sat for three years near the beach before I got it. It has rust/corrosion some of the outer surfaces, but the inside of the motor is unremarkable. Maybe just a bad day at the R1 assembly line?
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Old Today, 05:04 AM   #2
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Joined: Jan 2005
Location: Riding with my pal Richard Cranium
Oddometer: 4,682
Maybe carbon build up on the valve or seat ? Can you get a look in from the intake ?

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Old Today, 05:59 AM   #3
Joined: May 2015
Location: Springfield, MO Area
Oddometer: 38
Excessive clearance is usually indicative of a bent valve (it won't close all the way). However if that was the case you would probably have a misfire along with it.
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Old Today, 06:08 AM   #4
Beastly Adventurer
Joined: Oct 2007
Location: central USA
Oddometer: 6,632
With a new to you bike, it is possible you may not notice a misfire.

I recommend a compression check.

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Old Today, 09:00 AM   #5
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Joined: Jun 2012
Oddometer: 3,083
I would not be surprised if some prior owner did a valve clearance adjustment and put the wrong shim in, and then didn't bother to re-check clearances.
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Old Today, 09:31 AM   #6
Gnarly Adventurer
Joined: Nov 2014
Oddometer: 242
Kawasaki bikes of ZX11 series are well known to have intake valve gaps increase. Exhaust valves gaps decrease as usual.
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