Ignition - Aargh!

[Baffled]

Can anybody help please - I have run out of ideas? My 500 has a misfire under load which has progressed to the stage where it will start and idle beautifully, but as soon as I try to move off from standstill, the engine staggers and cuts out. I have gone through the diagnostics prescribed in the blue manual and I'm satisfied that I'm getting a good fat spark at both plugs, so current generation, transducers and pickups are working OK. But I still can't put any load on the engine. Any bright ideas?? Thanks, Baffled.

[morini500dave]

Hi,I've had a similar problem,try the cheapest option first if you have'nt already is change the spark plugs
Dave

[hendre]

and if you want to go for the expensive option: http://www.elektronik-sachse.de/ZDG3/MO ... ini_en.htm

[MickeyMoto]

Hi,

My 500 did this and it was down to carb sync. I could pull away with no throttle but as soon as I open the twistgrip it died, mind you they were way out.....

Probably doesn't explain the misfire under load, though. Could be the magneto coil breaking down under load?

Mike.

[boris tarpit]

. . Does the flywheel need remagnetising?? . .

[EVguru]

Most ignition problems are fuel related!

The reverse is also true!

Try opening one or both of the enrichment levers.

[Baffled]

Thanks for your replies, chaps. Your wisdom is appreciated. I'm tackling this by doing some more investigative work at the moment. My money is on an electrical component breaking down under load - the favourites would appear to be either the stator or the condenser part of the transducer. I'll post again when I have learned more. Cheers. Baffled.

[Baffled]

Full marks to EVguru! After exhausting all ideas on the electrical front, I removed, disassembled and cleaned the carburettors. There was not really much muck or anything in there, but I'm pleased to say that the bike now rides beautifully again. Not sure what it was in the end, but it certainly seems to have been fuel-related. (Could be something to do with the stuff we buy for petrol these days - it hadn't been ridden for six months or so and the petrol might have gone off or something like that.) Anyway, job done - for the moment, anyhow - and something for all of us to bear in mind in the case of running difficulties. Thanks to all who helped. Baffled.

[Daddy Dom]

Funny, this procedure also cleared up my ignition problems. Things were further improved by checking everything like float heights, the float-needle's Viton tip condition, that all jets were tight, plus a pair of Dell Orto carb service kits with all their new gaskety and O-ringy goodness. Hell, I actually just replaced every brass part I could source.
(BTW, if you do get the service kit you'll probably find a few things in the Dell Orto pack aren't needed.)
Cheers,
DD