Scooter just suddenly stalls while riding

[ma573r0fwar]

Hi all.

I am having some problems with my Suzuki SJ50QT scooter, which uses the same type of engine as the Suzuki Sepia ZZ.

about 3 times or so, in the last 1000km, it has randomly just stalled on me while in the middle of a ride. The way it stalls though doesnt just feel like the engine is just shutting off. It feels like something is jaming the engine up as when it happens, im usually stopped on the side of the road rather quickly. However, the last time this happened, the engine didnt stall, but it bogged down hard, as if something was putting excessive strain on it, when it stopped on the side of the road, the engine was still running, but at a slow idle (not rough, just slow). After pinning the throttle back, it took off again and rode fine. (I dont usually pin ther throttle)

Everytime this has happened though, when the scooter has stalled, it starts right back up again and rides fine, like nothing ever happened. The scooter is currently at the mechanic, and he checked my carburettor, but found no problems, hes also replaced the spark plug, but im certain this isnt the problem either as its cut out on a different plug also.

What could be the problem here? Is the scooter slowing down hard and fast normal if the engine has stalled while riding? Or is it an indication that something is jaming up the engine? If so, what could be jaming it up, is their anything in the transmission that could cause this?

Thanks

Nathan.

Also, the scooter has about 9000km on it (roughly 5592 miles) and is 6 years old (2005 model)

[mainepeace]

You may want to check the variator. The rollers could be worn unevenly causing the binding. Or it could be something in the clutch. Does it make any weird noises? Perhaps the belt is catching on something in the CVT case (assuming you have a variated system, of course).

Greg

[ma573r0fwar]

Hi Greg, thanks for your reply. The scooter is currently at the mechanic, but all he did is drain the carburettor and check the gas for water, in which he found none. Then he road it around the block a couple of times and said its running fine. I tried asking him to check the transmission, but he didnt and just said he thinks there is nothing wrong with it. I was wondering, id the rollers in the variator are unevenly worn, causing it to bind, wouldnt that stop the scooter from running completely? Rather then bog the engine down intermittently? Because like i said, the engine fires right back up again straight away, and the scooter can run fine for another 800km after.

[skuttadawg]

Does it bog or stall when you decelerate ? I had a tiny crack in a piston and I would have to give it gas just before I stopped to keep it running . Does you scooter have the same performance prior to the issue ? Does it do it at low and high speed ? If you have an EGR hose on top of the head remove while running and if you see smoke you may have a cracked piston like I did or other internal problem

[ma573r0fwar]

Hi skuttadawg. My scooter runs perfectly fine, as if nothing is wrong, right up until the very second it cuts out. I dont have any problems with it bogging down while slowing down either and everytime it has stalled, i have been doing about 50km, but its always just random. I dont think the piston has a cracked head, as the piston in there now is only 1500km old, and it did this once on the old piston aswell.

[wooddogg]

Did he change the fuel filter?

Also check to be sure the spark plug wire is tight to the plug.

Good luck, wooddogg.

[♣Luke♣]

ok, here's my precious suggestion: i hope imnts2 won't rudely jump in the picture and correct my statements again...seeesh!

do this: ride the scooter,as soon as it bogs down, remove the spark plugs and see if it's wet.,,if it is,then there is too much gas goin inside the combustion chamber, too much that the plugs cannot burn it...check the fuel system/ with emphasis on carb float and petcock and basically everything else that is essential in controlling the gas flow.

quote: " the scooter stall and start right back up as if nothing happens" ....exactly,, because when the time you are re-starting the scooter,the excess fuel inside the combustion chamber has dried up, then if you throttle up, gas starts flooding the plugs again,,,notice that it doesn't stall when idle?? because the gas flow is just enough for the spark pug to burn,,but as soon as you throttle it dies.....go figure..!

these are all based from my experience...not by the book!

remember,i owned a chinese scooter once in my life,,and i'd consider it the most exciting part of my life.,,it tested my "tolerance" (in every sense of the word)..lol

[relaxinrob]

You are occasionally pulling particulates through your fuel filter and it temporarily clogs your main jet. You need to replace your fuel filter with one that filters to at least 10 microns. Then you will be fine.