rough running

[robsgreen]

Hi guys
I recently rebuilt my bike and all seemed well. Ive done about 100 miles on it now and its developed a problem. When I start it from cold, it runs really well and idles smoothly. As soon as I take it for a run of say 5 miles and its fully warmed up, the idle becomes rough, almost like its miss firing which then causes the engine to start clattering ticking over and also the top end sounds a bit rough. When its cooled down, its completely back to normal, idling smoothly and quietly. The engine has been fully rebuilt. The carbs were stripped and cleaned by myself with all new jets including the slow running jets. I have balanced the carbs manually as per the manual. Is my problem with the slow running circuit? the bike rides well, revs cleanly and accelerates well, but on small throttle openings, you can feel / hear it missing. When I brought the bike, someone had stripped the 3 spark triggers off the back plate so these are set up as close as I can at 120 degrees to each other. the gap on the rotor tip is 50mm. how critical is their positions. I have also noticed the advancer can move slightly backwards and forwards along its shaft. Is this normal? I dont believe I have a mechanical issue as the engine is quiet and goes really well. If its the carbs, why would it run well warming up and then start playing up when its hot? I have been running it with un-leaded, but someone told me that super unleaded is better as normal unleaded can leave deposits in the carbs?Any ideas guys would be appreciated as always.
Regards
martin

[Goss]

Sounds like fuel starvation, usually these problems are at lower revs. May be worth checking the fuel tank vent.

Regards

Goss

[robsgreen]

Will have a look at the vent, but did notice when i was checking the plugs that one was finger tight and might have been leaking when the bike was hot? will try it this weekend to see if there is an improvement.

[EMS]

It may be a long shot, but sometimes, bad coils show when the bike is hot.

[NobleHops]

It may be a long shot, but sometimes, bad coils show when the bike is hot.

I think I read a cool trick here - removing the tank and running the bike in the dark to see if sparks were visible through cracks in the coil.

[robsgreen]

Hi guys
The coils are brand new so hopefully there shouldnt be a problem there. I will take it for a run this weekend. Might also try and turn the air screws out another 1/4 turns out as well. currently set at 2 1/4 out.
keep you posted

[Mouse]

Check your plug wires.Problem could be a loose connection.
I had new wires but bike would drop 1 cyl when hot and cruising along found No# 3 cyl wire not properly attached to NGK plug cap.

[robsgreen]

Yes, good point. Will check this out as well
Cheers
martin