Bonneville America Forums Forums Technical Forums General Tech Loose exhaust valves

Good evening all:

Am hoping to get some advise about how to proceed with some loose exhaust valves. The ticking under the valve cover has been quite loud. So on Sunday I pulled the valve cover (whew!) and measured the clearances. The intakes are OK, but all of the exhaust valves are loose. With the worst the .305 feeler gauge doesn't really drag, but the .330 won't go.

I've read the tech vault proceedures, and searched the advise elsewhere (link), but I'm wondering how bad these numbers really are.

Is this something that I can sit on until the riding season is over, or do I need to get a round-to-it. Thanks.

You've already been in there and now have experience with the cam cover, right? Removing the cams and doing the shims is not that much more work. Personally, I'd do it now.

Thanks Phil. I had put it all together again, and was hoping to do it during the winter. But I was feeling kind of guilty about it, so thought I'ld ask. If I get the list of parts except the shims ahead of time from the dealer (the dealer is 2 hours away), and get the shims from the local Yamaha dealer after I measure the old ones, hopefully I can minimise my down time.

I got the bike in September, and only have about 10,000 Km on it. Kind of surprised they were that loose since it's only halfway to be needing to be checked.

It is better to be too loose than too tight. Usually the valves hammer the seats and tighten up on the clearance. I don't think being that much over will hurt. It is only .030mm. I'm in the same situation as you. Measured my valves and have two on the rt cylinder at .330 and .335. I want to get them around .227. I'm getting some backlash tools made for the cams. Triumph dealer is 8 hours away so hopefully the local Yamaha dealer keeps enough shims in stock so that I won't have to wait for them with the bike apart.

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I want to get them around .227

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I assume that was a typo? Exhaust valve spec is 0.25 - 0.30mm