KymcoForum.com
Scooters - 125 to 300 => Grandvista 250 => Topic started by: Hueffenhardt on April 12, 2014, 08:49:41 PM
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I am attempting to adjust my valves. I know what top dead center will look like when it is there, but I don't understand where to find what I need to crank to turn the flywheel to top dead center.
On the muffler side, just above the motor oil dip stick, I found a plate with the word "KYMCO" on it. I removed it and found what almost looks like the top side of a spark plug. Is that what I am supposed to turn? I can't seem to find a socket in my set that really fits it and there was a tool that came with the scooter that is stored under the seat that doesn't seem to fit either. But, is this even the right thing I am supposed to turn? Help please.
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I solved my own problem. The answer is on the transmission side of the scooter. When I take off the cover for the transmission there is a crank shaft that one can turn (19mm socket) that turns the flywheel by means of a chain.
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You have to align the two small holes on the sprocket with the cylinder head edge, so the big hole is on the top.
(http://i813.photobucket.com/albums/zz56/als01seville/ALS-TRIKE/CAMSPROCKETTDC-1.png)
Also the T mark on the magneto wheel, from the right side of the crank case, for the 250cc engine, here is a little plug that needs to be unscrewed to view the magneto wheel markings. The T mark on the magneto wheel needs to be visible trough that hole. Something like this:
(http://www.scooterfocus.com/timing.jpg)
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Take the sparkplug out first. Otherwise you will be fighting compression.
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I can't seem to find a socket in my set that really fits it ... Help please.
I used a standard 3/8" 20mm deep socket.
Download My pictures. You will see my air impact tool which is not needed.
http://www.wecandobetter.com/dnload/Kymco/Valve_Adjust_Sparkplug.zip (http://www.wecandobetter.com/dnload/Scooters/Kymco/Valve_Adjust_Sparkplug.zip)
Since this is a single cyclinder, single cam motor you can remove the spark plug to make the motor easier to turn and once the piston is at top dead center you can adjust both valves at the same time. You know you are at TDC because the cam is not pushing on either valve. If you continue to turn the motor you will see one valve open then the other then TDC. Take your time adjusting. I made my valves too lose and had a distinct "ticking" noise which is incorrect. Went back in and readjusted to correct spec and no more ticking.