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kingofstlouis

Yz426f Adjusting Valves, Shim Stuck!

11 posts in this topic

Anyone with any advice on how to get these bad boys out would be awesome right now because I just don't get. Period. I've adjusted valves before with no problem but this time the two exhaust valve shims (or called pads in the manual) will not budge from their place. When I pulled the lifters out the shims were not stuck inside the lifter like normal, they were still seated in the valve top. Usually not a problem because a maget or even tabe will pull them out... but the shim is seated in there tight as can be. I've tried magnets, tape, taps, prying, and praying. Nothing. My next idea is to glue/epoxy a nail to the shim and pull up on it that way, or an even more desperate measure would be to take a drill and easy-out to it... but that's a ruined valve waiting to happen.

I can't just leave the shim in there because the valve clearance is considerably out of spec, and I've looked everywhere for someone with a similar story but have found nothing. Thanks in advance to anyone who offers anything in the matter.

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A pin punch, light tap with a hammer on the shim edge. May have to tap on the edge in a few spots to break it loose. Have the magnet touchig the shim as it might pop out and it would suck to go flying down the cam chain cavity. Once it is out, you need to determine why it stuck.

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It sounds like it could work, especially if I can find a small diameter punch. If I hadn't just cleaned up for the evening I'd go out tonight and work with it some more, but I'll mess with it tomorrow and let you know if it works. Any ideas why both of the exhaust stuck while the intake shims came out like usual? I wondered if the owner before me used the wrong shims or something. Just a thought... Thanks!

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What absolutely works is to tap on the edge of the spring retainer, rather than the shim itself. What this will do is to rock the spring retainer down slightly relative to the valve stem, while the valve stem will prevent the shim from following that rocking movement. DO NOT get carried away with this, or you may dislodge the keepers and end up removing the entire spring. Start with some prudent tapping, keep a magnet nearby as suggested, and the shim should come out quite readily.

Alternatively, you can set a socket or tube on the retainer that's large enough not to touch the shim, and tap the retainer just hard enough to make the valve bounce off its seat. The shim will be ejected by inertia, and remain inside the socket.

The exhaust valves use larger springs and retainers. The shim pocket may have been made to a very slightly smaller dimension.

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Got it all buttoned back up this morning, thanks to the suggestions the shims that I worked on for hours last night came out in seconds... sincere thanks!

It started easier than ever, but still stalls out once the cold choke is put in. I'm thinking I need to play with the pilot screw some, though i did count the turns inward before removing it. For all I know the guy who had the bike before me never had it right in the first place...

If I give it gas it revs up beautifully, whereas before I adjusted the valves and cleaned the carb it would die when given gas. So progress was made.

Thanks again for the suggestions, and I look forward to future posts!

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It started easier than ever, but still stalls out once the cold choke is put in.

That's not that unusual. There is a period of time as the bike warms up when it begins to be too hot for the choke, but not quite warm enough to idle on its own yet. Always do your setup of the pilot with the engine at full normal operating temps, like after a 10 minute ride, at least.

You may want to review these two links:

http://www.thumperfaq.com/jetting.htm#PJ

http://www.thumpertalk.com/forum/showthread.php?t=327405

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And the fun continues...

She starts and rund beautifully now the new jets are in place and everything set up properly. A new problem... coolant overflows after about 5 minutes of riding. THe levels should be perfect since I just added the spec amount a few months ago. If anything, they should be low by now, not high. I don't want to it to overheat and cause a whole new string of problems, and I don't want coolant pouring out all over the place. Could a seal or something be bad to cause this?

Also, a quick question about how a sensor line is run. Coming out right in front of my gear shifter is what looks like a sensor, and it wearves up under my carb around to the right side of my bike. It dangles close to the exhaust , it looks like it's about to melt. Any ideas on the "proper" way it should be routed to prevent this? Thanks!

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Awesome tech tip from Grayracer513 to use a socket and tap on shim retainer. I had the same stuck valve shim problem on my FZ1 streetbike and this procedure cured the problem pronto! THANKS!!

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And the fun continues...

She starts and rund beautifully now the new jets are in place and everything set up properly. A new problem... coolant overflows after about 5 minutes of riding. THe levels should be perfect since I just added the spec amount a few months ago. If anything, they should be low by now, not high. I don't want to it to overheat and cause a whole new string of problems, and I don't want coolant pouring out all over the place. Could a seal or something be bad to cause this?

Also, a quick question about how a sensor line is run. Coming out right in front of my gear shifter is what looks like a sensor, and it wearves up under my carb around to the right side of my bike. It dangles close to the exhaust , it looks like it's about to melt. Any ideas on the "proper" way it should be routed to prevent this? Thanks!

No idea on the wire, sounds like a gear position sensor, not a stock item for the YZ. Just a guess tho...

As for the coolant, is it boiling over or just seeping out and then stopping? If you overfill the rad, the displacement of the coolant will increase when at operating temp. It has to go somewhere, and out the pressure cap it will go. However, if your boiling over and more coolant is coming out, and your levels are now below the inner core, or you can't see them, then you have an issue. The rads on these bikes have excellent heat transfer, even slow riding with low throttle will bring temps down below boiling no problem.

If your coolant is disappearing and getting too low, a bad head gasket is usually the cause of this. Hot exhaust gasses from combustion force themselves through the problem area of the head gasket. They make their way into the oil and/or the coolant, displacing it and increasing temps causing it to boil over quickly and def under load no matter what speed.

Have you done any head work? has the head been off the bike since this problem happened?

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Have you done any head work? has the head been off the bike since this problem happened?

You understand that this thread is almost 2 years old, right?

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