New T20 problem

doug rooney · Post by **doug rooney** » Sat Jul 04, 2009 11:38 am

Took the bike for a test run this morning. I have noticed at times what seems to be a loss of power but today it just died 1.5 miles from my house. Pushed it back for a ways and tried it again. Started up and I took off for just a short time and died again. It's like I just turned the key off? Seems to start ok once it's cooled down. Any hints? Thanks

advant63 · Post by **advant63** » Sat Jul 04, 2009 1:07 pm

i'll take a guess. coil failing when warmed up.

elbert · Post by **elbert** » Sat Jul 04, 2009 1:33 pm

I would guess a problem with the coil too. Bring a spare spark plug to be able to quickly check for spark when it stops, and don't drive too far from home. I belive the coils from the T250/350/500 and the GT250 will fit if you need replacements but I'm not 100% sure.

tz375 · Post by **tz375** » Sat Jul 04, 2009 7:40 pm

Condensor? It's the classic symptoms of a failing capacitor across the points.

Or blocked fuel vent in the tank filler cap.

doug rooney · Post by **doug rooney** » Sat Jul 04, 2009 8:48 pm

My first thought was the coil too. Will check that out and get a couple new condensors. Trust me, I won't go that far from home again until it's right. I pushed that sucker on a gravel road and up a hill for about half the distance. Thanks guys.

doug rooney · Post by **doug rooney** » Mon Jul 06, 2009 9:36 am

Big problems I fear. What I didn't say in the initial post is that I notice a significant knock from the right cyl. Can even feel it when my hand is on the muffler. I think it is related to the lack of oil to that cylinder and the pump problems I have posted before. Smokes nicely out the left pipe but very little out the right. Have tried 2 oil pumps and same air problem persists on that side. I think it runs ok when cold because the piston has contracted but when running awhile, it swells and seizes the engine due to lack of lube. I am away from home for a couple weeks so won't be able to work on it til I get back. Going to take it apart as far as I need to in order to find the problem. May have to get a new piston and redo the cylinder. Won't know til I get in there. I think the check valve oil passage into the cylinder may be the culprit. Oh well, will keep me busy for awhile longer.

Coyote · Post by **Coyote** » Mon Jul 06, 2009 2:16 pm

In your first post you said "It's like I just turned the key off?" A seized piston would feel more like you hit a wall and it tends to flip your butt over the handlebars.
The knock could be nothing more than extreme pre ignition. If that's the case and you run it that way, you're headed for a holed piston. So while you are purchasing new condensors, pick up a new set of points too. Then re gap and set te timing again.

doug rooney · Post by **doug rooney** » Thu Jul 09, 2009 2:22 pm

Thanks Yote,
On one of it's last starts and stops (Dies), the back wheel DID lock up and drag in the gravel. That was in about 3rd gear at only about 20-25mph.