Scooterotica

Guys, had a muggy 185 (mate's) which was running poorly at weekend in that after running for about half mile it would suddenly just die. I had a go and found he was riding it on normal petrol and the tank was virtually empty, so thought it was dying because the petrol was not turned onto reserve, then looked down and found petrol peeing out the carb and a puddle on floor. SO we put another 22mm Delorto on the bike, filled the tank with petrol and it ran much better.

Before the above we changed the CDI as there was intermittent sparking, so I believed we had dealt with two problems at the same time, all was well, and he went home. Then yesterday he did a 10 mile ride on it, and all was fine, but he said when riding the bike back from he's ride it felt hesitant and he struggled over 30mph . OK so we thinks, lets just change stator (as we had done the other usual change overs) , which we replaced with a new BGM one. As we were setting the timing and I had the strobe gun on the flywheel I noticed the flywheel was moving inwards and outwards ??? and on low revs the bike was fine, but on mid to top range it was backfiring/mis-firing.

On further inspection , me physically pulling on the flywheel there was some sideways play through to the chaincase (as though all was moving a few mms) . A mate said try tightening up the front sprocket screw which may have come loose and the crank thus moved out slightly into the mag flange. I tried the sprocket bolt but that seemed to be torqued up correctly and no wear mark at all was found inside the chaincase as you might expect.

I'm presuming the flywheel movement is enough to cause the problem above with mis-firing , anyone had this before ??

Could your main bearing on the drive side be either worn or loose allowing the crank to move in and out when you pull and push the flywheel ?

Yes it turned out to be the main bearing and a very worn out L.I crankshaft. All now replaced with GP crankshaft and new bearings and seals......We found a number problems, but ultimately the issue with it cutting out seems to be a work throttle slide on the SH 22 carb.......now has a Jetex (for now) and running well all round

I'm running in a GT186. At 1/4 throttle its fine, hold it at 1/2 throttle for a minute or two and it dies. Twist the throttle open and it bursts into life. It died a couple of times, started up again no bother. I changed the plug but that made no difference. Can't see it being carb related as it runs fine when cruising. Stator?

Good point a.j.....admittedly the stator was changed firstly from a BGM model to a standard SIL one, but it still did it. Then the carb was next fitted and bingo issue resolved and he's done a thousand miles since. I must confess however, the carb is drinking too much fuel so think he needs to get it dyno'd and down jetted I guess..

This is it you see. At 40 mph (still running in) it slows down fine at junctions. But doing 45 mph + for a fair length of time, it dies at junctions, yet starts first/second kick again & I crack on. Cant see it being a carb issue surely, there's no intermittent running problem when cruising, or starting issues. Yet if I shell out for a new stator & it is the carb, well, wasted my money haven't i.

the way you describe it it could be running out of fuel, check your filler cap has a hole so its not airlocking, then i would do a flow test out of the fuel tap and see how long it takes for a pint of fuel to come out, if thats ok check the carb filter and fuel lines for blockages, or just replace, what carb are you running ?, check internals jets and fuel valve for blockages and debris, if all ok it could be electrical. i would change plug and cap followed by cdi, i presume your electronic, if still gives the same symptoms could be stator, also try with your green wire to the ignition switch disconnected. a lot of things to try, good luck im sure you will find the problem with a bit of trial and error.

holty

Just did it on a dyno. Carbs set up properly. Got to be electrical. Something is making it cut out at persistent mid range. As soon as it dies and comes to a stop it fires up first kick. Could be the Augusto...