Hi everyone,
I have a 2001 Yamaha Wolverine that I bought last year. Runs great but has always had a little trouble starting. If I put the choke on it starts right up but without choke it's tough. So I finally decided to adjust the valve clearances. I've never adjusted valves before but have the repair manual. So I started by taking out the spark plug and finding top dead center. I then adjusted the intake valve which was a bit loose, so I tightened it up until it was within spec. I then went on to check the exhaust valve and found that I couldn't get any feeler gauge to slide in, so I loosened the jam nut and tried to loosen to the adjustment screw and the screw would not turn at all. I tried to use a pair of needle nose pliers and it still wouldn't turn. I was wondering if anyone could tell me what would cause this to happen? I was wondering if I mistakenly didn't have top dead center on the compression stroke if this could cause the tightness on the exhaust valve and make it so the valve was too tight to be loosened? If that isn't what would cause that too happen, does anyone know what I can do to get the screw to loosen so I could get the valve clearance within spec.

Any input would be greatly appreciated! Thanks

 

Check that you haven't been on the exhaust stroke by turning the crank through 360 degrees. If the exhaust valve goes down, you were on the right stroke before, if it doesn't, and the valve now has clearance, you were on the wrong TDC, but will now be on the right one. I stick my finger on the plug hole, if it is trying to blow it off, I know I am on the right stroke. I don't know why Yam uses those stupid square adjusters, screwdriver slots make life easier. I guess you could buy the official adjuster tool.

 

Hey there,
thanks for the reply, I will check that out to see if I was on the wrong stroke and the tip about putting your finger over the plug hole sounds like a good way to know. One of my buddies mentioned a trick he used to do on an old dirt bike by putting a screwdriver in the spark plug hole and turning the crank lightly and the piston would gently hit the screwdriver head which apparently would also do the same thing though I'm not crazy about that idea. Thanks for the advice, I'll try it out and let you know if I got it worked out or not.

 

Very simple on a 4 stroke to find TDC. Don't get confused by intake,compression,ignition and exhaust strokes. If you have access to the crank shaft nut,just turn the engine over slowly and look at the intake rocker arm(s) only. As the rocker arms push the intake valves down and begin to come back up,you can place a straw if need be in the spark plug hole. Watch as the straw reaches the top of it's travel.You should have another plug to check for the tdc mark. You should be right on it or very close. Then you can adjust the valves.