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  #1  
Old 05-29-2004, 12:43 PM
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Default how to tell if you have bad valves

Earlier this week I had a post about valve adjustment and I couldn't get the right clearance. Well I still can't I don't know if it is my fault because I'm mising something but I have at least a 1/4" clearance from the bottom of my rocker to the top of my valve I don't know if I am checking it in the right spot or what but when my timing marks are lined up there is a huge gap and when I turn the engine to the end of a compression stroke and my intake valve is pressed down if I set it to .010 there and turn it over some more my rocker arms still have a 1/4" play in them so I did both sides like that anyway just to see if that is where you check it and presumed to crank it up They started clattering like hell so I assume that wasn't the right place so if I could get some step by step instructions or how to troubleshoot bad valves Please help me because I hate being withou my 4wheeler. Also could I just need another top end and the lack of compression could not get my valve all the way up?
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Old 05-30-2004, 12:37 AM
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Default how to tell if you have bad valves

You want the timing mark to be at the top of the compression stroke to adjust the valves (both intake and exhaust will be closed - For every 1 revolution of the cam, the crankshaft rotates 2X's, so you can actually see the "T" 2X's in one complete "cycle" of the engine). Once you are at TDC on the compression stroke, then insert the feeler gage between the top of the valve and the bottom of the rocker arm adjuster screw - adjust the screw until resistance is felt on the feeler gage - you should be able to remove and insert the gage with slight effort - then tighten the lock nut down - recheck with the gage to ensure adjustment hasn't changed (sometimes the lock nut will change adjustment)

I've seen quads with bad rocker arms, cams, etc - usually you run out of adjusting screw when trying to set the valves on them.
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Old 05-30-2004, 02:49 AM
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Default how to tell if you have bad valves

What you can do also if you want ot double check is pull the spark plug, and rotate your engine while holding something like a screwdriver so it won't fall into the cylinder due to the handle down through the hole. When the screwdriver starts to come up against the piston towards top dead center AFTER the intake valve has opened when you go the valve covers off then you know your for sure at TDC on the comp stroke. To get it as accurate as possible, just pull them plugs and after the intake valve has lifted be really really slow not to overshoot the T mark on the flywheel when looking with a flashlite and pulling the recoil or turning it over with a rachet on the crank to line it up. I've done it both ways and had really accurate results. I'd do it the way the manual recommends, call a shop and ask for the clearances or someone on here will post it for you if you ask. Try to use a solid breaker bar instead of a rachet to prevent the flywheel from overshooting the T (TDC) mark on the flywheel, that gets real annoying and easy to get an unaccurate valve adjustment. You can tell when all this needs done bad the more the mottor starts to "TICK" mostly heard at idle.
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Old 05-30-2004, 09:30 AM
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Default how to tell if you have bad valves

So if I do everythimg that you guys told me and I set my valves with them compressed down and at top dead center and when they are not at tdc the rockers should follow the valves right and not have free play betweent the valve and the rocker so if this persists I guess that mean s something is shot and I better look on ebay but more better I see a alba power up coming then when this is fixed it's sold and banshee is on the way
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Old 05-30-2004, 10:54 AM
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Default how to tell if you have bad valves

Alright I just went outn there and tried again and the best clearance I could get is about 1/4" and that's the closest point where the adjustment screw touches the valve So I guess something must be bad wrong. Could the timing being off cause something like this if so how do you check the timing with a light on an atv and also more suggestions about this problem will be greatly appreciated
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Old 05-30-2004, 01:43 PM
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Default how to tell if you have bad valves

Ignition timing has nothing to do with your valve clearence problem. Even cam timing has nothing to do with a "too much" of a clearence problem because the heal of the cam should be on the rocker arm anyway.

Like quadwrench said, you might have a bad rocker arm?

It would be of help to say how all of this came about? Did it run fine and one day you wanted to run the valves and now you have this problem? Did you put a new cam in and now you have this problem? You get the point I'm driving at.
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Old 05-30-2004, 03:05 PM
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Default how to tell if you have bad valves

It cranked up and ran fine but I just started noticing more smoke at the top of the gears and a dramatic power loss so I posted the power loss problem on here and about 4 people said the valves and that just kinda made sense to me also so I then went ahead and took the plastics off and the valve covers off then so I wouldn't damage it anymore and when I actually looked at the valves there was like a 3/8" gap between the rocker and the valve so I am beginning to suspect that was a big problem because I can't even get them close to specs I follow the book step by step and they're not even close I was just wondering what problems could make this happen
Update: I just tried to crank it up and it wouldn'[t even attempt to What I did was just adjust the screw to where it's just enough to stay with the valve without any play and I guess that was the wrong thing I think I just need a new everything in the head
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Old 05-30-2004, 04:44 PM
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Default how to tell if you have bad valves

Not just in the head man, sorry to say, if you have done that much damage, a good chunk of the engine could be damaged if you drove it that long. All them fillings in the head from the worn down rockers and cam have made their way to the bottom end and to the oil pump. Now them fillings have made their way through the entire engine. That's alot of stress. If you would have caught it right away it wouldn't have been that bad, but hearing from what you said the pads on the rockers either wore down completely, and/or the lobes have significantly been damaged on the cam that they don't have the lift they once had. Unless you take pictures there ain't much more any of us can say. Pictures, or a vid of how the quad is running and what not. I've never ever heard of a quad with that much clearance in the valves on the worst of damage I've ever seen at the shop I've worked at. I really don't know how your quad can run setup like that. It must barely be lifting the valves to allow fuel and gas to enter/exit the engine, and that's why you have such a bad power loss. You could change the cam, rockers, and valve guide seals/seats, but that doesn't fixed the problem of the fillings having made their way through the entire engine. No matter how well you clean it, how many oil changes you do, the oil pump could be damaged and the crank bearings amongst the many bottom end bearings could be detrimentaly damage and could go at any point!
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  #9  
Old 05-30-2004, 09:11 PM
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Default how to tell if you have bad valves

Thanks for everyones input I took everything into consideration I have the head off now so later tonight or first thing in the morning I'm going to tear into her and check out everything in a first hand view as of right now the bottom of my valves and the top of my piston is black like it has been running rich which I suspected I don't think my 150 main jet is to much with my pipe and filter when I get her running I might have to take about a half turn out of my pilot

update: I now have the cam out and it looks good on the tops of the lobes but on the side of the intake there seems to be a little chip on it but it seems to be smooth as if it came from te factory like that. I'll update the further I get into this and thanks for everyones help
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Old 05-30-2004, 09:11 PM
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arms, atv, bad, check, end, motor, replace, rocker, shot, start, stays, timing, top, valve, valves, wheeler



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