Tight Exhaust Valve=Hard Starting?

3 replies to this topic
  • finglan

Posted November 04, 2002 - 03:06 PM


The last time I took my bike out it became harder and harder to start each time I shut it down. I changed the plug with the same results. I then tried to slightly adjust the pilot screw which made it way too lean.

Since then I have cleaned the carb throughly twice and tried all kinds of different jetting. I had over 400 miles on the old jetting w/out any problems. This led me to believe there was something going on besides the jetting, but I could not find the problem. I do get a good spark on the plug, so the coil must be fine. The bike was either too rich or lean as I tried every jet in the series. It would also kind of give out a fart from the tail pipe when I shut it down. I had the stock 165mj in when I had the original problem and recently noticed that there is a small spur just inside the rim of the jet. I have no idea how it got there. It may have caused some of my problems. I have tried so many different jetting setups that I am convinced there is another problem.

I just checked the valve clearences and found one of the exhaust valves to be .025mm too tight. The stock pad was a #175 so ordered a #170. All the other valves have not moved at all since I checked them last year.

Would a tight exhaust valve cause any of these symtoms?

I plan to take another look at the carb to see if there is something that caused the spur on the mj. I have never seperated the section held togather by the four screws w/the yellow paint on them. Is there something I should watch out for when taking this section apart?

Is there anything else I should look for?

  • sabin

Posted November 05, 2002 - 09:03 AM


if it was .025mm (how do you measure it to 0.005mm?) and it has to be 0.20mm-0.25mm and your pad is 175 you have to order pad#155 to make about 0.23mm clerance

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  • finglan

Posted November 05, 2002 - 10:31 AM


I thought the pads came in .05mm steps. This would put me right in the middle of the specified range. I was at .175 + the .05 would put me at .225

  • sabin

Posted November 05, 2002 - 12:27 PM


Pad# 175=1.75mm you can easily measure it...


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