2008 Sunl 250 Wont run.... By thetucks (Read 5,822 times)

[thetucks]

Ok on the flywheel...It has several different marks. from left to right it looks like this.....
I I II

which mark should be set at top dead center with the timing cam?

[kz1000st]

Don't know. The easiest way to find TDC is to remove the spark plug, stick a pencil in the hole and rotate the crank a few times back and forth until the pencil sticks out the most. Then look at those marks and you'll have your answer. I would say the timing is still off. The banging is the engine telling you how unhappy it is that the valves are opening and closing at the wrong time.

[thetucks]

thats what im thinking....the timing chain has been off from the previous owner so I dont know where to put it. I can set the piston at tdc and move the cam to match but the marks on the flywheel dont match.

[thetucks]

I can put my timing light on it and it shows a single mark but is about 1/4 inch away.

[thetucks]

[thetucks]

Ok im on the hunt for a replacement valve cover and rockers. I think there is a problem with mine.

[Alleyoop]

The index mark on the flywheel is behind the large chrome plated screw on the oil fill side of the engine.

loosen both adjusters loose let the adjusters fall to where ever they want to, one or both could flop over.

remove the cvt cover, 2 bolts usually.

turn the engine ccw with the variator nut till you see the index mark.

both adjusters will be level if you are at tdc. note if you find the index mark and one adjuster is flopped over (still loose) you are 180 degrees out turn again till you find and both adjusters are level.

push each adjuster outward then back 1 mark tighten the bolts down..

IF One of the THE VALVE ADJUSTERs is NOT like the other then you are off on the cam chain.
Alleyoop

[thetucks]

I tried that last nite. the intake side will go all the way to the outside and never feel any resistance. the exhaust side does. I have lined up the piston all the way at the top with the cam and it is dead on the second mark(im assuming its the f mark, the first I think is a t mark). when I run the scoot at idle I check with my timing light and the mark is a hair to the right of the notch. and it still wont throttle up.

[thetucks]

okay guys I have got back on the scooter again last night trying to get this thing going. as it turns out I put my timing light on and when I start to throttle up the fire actually cuts out. that is what's making it miss when i throttle it up. the timing is not off. I have already verified that the CDI is good by swapping it with a known good one what else should I check?

[thetucks]

Anyone ever have this happen before? I also noticed that if I have it idleing and I push the kill switch to the kill setting it stays running. but if I push the kill switch to the kill setting and try to start it the scooter wont start. shouldnt it kill it if its running?

[Alleyoop]

Apr 8, 2014 5:54:03 GMT -6 thetucks said:

I tried that last nite. the intake side will go all the way to the outside and never feel any resistance. the exhaust side does. I have lined up the piston all the way at the top with the cam and it is dead on the second mark(im assuming its the f mark, the first I think is a t mark). when I run the scoot at idle I check with my timing light and the mark is a hair to the right of the notch. and it still wont throttle up.

both adjusters will be level if you are at tdc. note if you find the index mark and one adjuster is flopped over (still loose) you are 180 degrees out turn again till you find and both adjusters are level.

[thetucks]

Alleyoop...thanks for explaining it for me. I believe I have them set. What would make it skip spark once I try to rev it up? That is what's happening.

[Alleyoop]

I tell you sure sounds like it is 180% out of time bud.

Now lets go through this again one more time to see if you did it right:

If you loosen BOTH BOLTS on the Valve Adjusters and you bring it up to TOP DEAD CENTER BOTH ADJUSTERS should be loose to the RIGHT. And you should be able to easly move them LEFT and they should be pretty much centered.
Alleyoop

[thetucks]

I have turned the cam 180deg just to check that and it wont stay running there. can you explain something to me? there are 2 times where the piston is at the very top. and on both of them the notch lines up on the flywheel. how do you actually know which one is which? I have tried both and the one I have it at now seems right. I have it set now where its suppose to be. its running the best it ever has. its idleing at 1500rpm but when I try to rev it up it skips the spark making it cut out.

[kz1000st]

It doesn't matter. That timing mark fires the spark plug on both strokes-compression and exhaust. It's called a Waste Stroke. You just have to make sure the cam has both valves slack when the piston is at Top Dead Center. I screwed up the cam timing on a Volkswagen Dasher years ago and it ran like your scooter. Once I got all the timing marks aligned it ran like a sewing machine.