possible bent valve

[spawningvat]

hey everyone:

So, along with this thread, http://www.thegsresources.com/_forum...d.php?t=116114 I managed to get my cam chain tensioner back on.

I rotated the engine with my hand on the kickstarter, and the rear wheel in 6th gear, and the engine would lock up in both directions. I checked the timing and I was off, meaning the chain jumped gears. So i retimed everything. I bolted everything back together, started it, and while running, noticed that there is alot of valve chatter, and #2 exhaust is not getting hot. I opened everything back up, and I see about 1/16th inch of space between the cam lobe on the exhaust tappet shim for the number 2 cylinder. So the valve isn't coming back up. I can gently pry the tappet up to the cam, but it falls back down on its own.

Did i bent the valve? How hard is it to replace? Or is there something else i should be looking at.

Thanks again.

/s/ Sean

[Steve]

If it falls back on its own, I would be looking more for a broken spring or retainer at the top of the valve. I would not rule out a bent valve, but since it does not stay up on its own, it's obvious that something is not holding it there, and it's the spring's job to do that. 8-[


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[tkent02]

So the valve isn't coming back up. I can gently pry the tappet up to the cam, but it falls back down on its own.

So the valve is stuck down, the shim bucket is moving freely up to meet the cam lobe? Probably bent but at any case you will need to take it apart to find out.

I almost added a caution to check the cam timing before turning the engine to the other post, didn't bother. Sorry.

[spawningvat]

Either way, I still need to take the exhaust off and the head off to check, right?

[TheRedlineMan]

As Steve said.

The head is going to have to come off, even if the valve isn't bent, in order to replace the missing retainers (by the way can you see the retainers and the cap they hold in place?). There is a high chance that the valve has been damaged. The valve guide and seat will need checking. The top of the piston could also have been damaged.

What's the story with the motor? has it recently had any headwork done? It's not common for the retainers to come out unless the motor has been seriously thrashed.

[spawningvat]

I owned this bike for 2+ years, and its at about 42,000mi. It was supposed to be my girlfriend's bike, but she rode it less and less this season. As of 3 days ago, it was running, but i thought it was a little noisy while idling. During ownership, I adjusted valves, replaced tires, chains sprockets, brake fluid, plugs, carb to head boots, and replaced all the stupid philips screws with ss hex bolts. I wanted to clean and adjust the cam chain tensioner, and thats when i started causing more problems. Now i'm wondering if its worth fixing anymore. Any insight on keeping it would also be appreciated.

/s/ Sean

[Suzuki mad]

If you sell it as spares you won't get much money for it. Buy a new bike will cost you a lot more and getting a second hand bike will be buying a total unknown.

You have a good bike. Yep you made a mistake. We all do that!!!!! So why compound it and get ride of her. Its not that hard to get the head off, check the valves and repair the bike. It will be an experience that will bring you closer to your bike, giving you more pleasure each time you ride her.

If you were close to me I'd enjoy stripping it down and repairing it.

Suzuki mad.

[Nessism]

Almost certainly a bent valve. Not the hardest repair but a lot of work and it's going to cost you some money in parts. You are going to have to buy a gasket kit, and replace that valve.

Good luck.

[tkent02]

Could keep an eye out for another engine...I got an 850 engine on ebay last year for $1.50, just keep looking... or a parts bike on craigslist.

[49er]

Almost certainly a bent valve. Not the hardest repair but a lot of work and it's going to cost you some money in parts. You are going to have to buy a gasket kit, and replace that valve.

Good luck.

If the valve stem is bent, you should be replacing the guide as well. It will be scoured and slightly oval through running in that condition. It may be time to do a complete top end OH while you've got the head off!
The piston will have some damage as well.
If money isn't an issue, do the repairs yourself, learn from the experience and enjoy the ride.

[Nessism]

If the valve stem is bent, you should be replacing the guide as well. It will be scoured and slightly oval through running in that condition. It may be time to do a complete top end OH while you've got the head off!
The piston will have some damage as well.
If money isn't an issue, do the repairs yourself, learn from the experience and enjoy the ride.

Since the engine was just damaged I doubt there will be any issues other than the bent valve in question.

I'm not sure how much valves cost from a dealer but I've seen some new ones on ebay recently. Worth a check.