Faulty coil ?

[tomo]

Been noticing recently on rides out, that at around 45-60mph the bike feels like the bike loses a little power, almost like missing on one pot, difficult to describe but then picks up and runs ok again. Last week-end, see my post in the discussion area, had to change the kill switch/starter switch gear. Went for a ride but found the revs slow to drop. Checked and it was down to a cable adjustment, when the bars were turned to the left the throttle was stiff to return. So adjusted, made sure throttle snaps back when bars turned fully right and left. Took her out again and bike ran like crap and could not get above 30mph, also revs still slow to drop. Back home a check showed no spark at No1 and No4 pots. Guessing there is a faulty coil ?, could explain the slight missing over the last few months, but seem to recall when a coil goes bad it is pretty much immediate. Would a dodgy condenser be more likely ?. As for the hanging revs, could that be connected in any way ?. I know that is a classic symptom of an air leak at the carb/engine manifolds or carb/airbox, but it only just started after I changed the switchgear and adjusted the cables. Best part as mentioned in my other post, the odometer is reading 66642 !. Any thoughts or advice on this would be appreciated. Have`nt had the chance to try investigating for loose connectors etc yet.

[Nessism]

Is the charging system working and do you have a good battery? The DC voltage across the battery at 5000 rpm should be in the range of 14.5 V. Are the valves properly adjusted?

[tomo]

Thanks for the reply sir, much appreciated. Charging system checks out ok and the battery is good, only recently fitted a new one. Valves I need to check, been a while since I did that last and she is a bit tappety. Still thinking coil or condenser for the sparkless 1 & 4.

[Grimly]

GS coils are very long-lived, but when any coil fails it's fairly common for them to fail when hot.

[tomo]

Problem solved and I am feeling like a bit of an idiot !. Took the tank off today to get at the coils and the one for pots 1 & 4 had one of the terminals disconnected, think I must have caught it when putting the tank back on at the week-end. Connected back up and very carefully put the tank back on. While I was on, also noticed the vacuum pipe to the petcock was a loose fit, so snipped the ezpanded end off and re-connected. Good fit now and tightened up the clamp. Took the bike out for a test spin and ran fine. Also noticed the hanging revs issue much improved, so guessing the loose pipe may have been to blame there. Revs drop ok now, but not as quick as they should, so suspect an air leak still, but have to wait until I win the lottery or can save up for new intake & carb boots. Can`t believe how much those are now !!. Anyway, thanks for the replies and advice guys, much appreciated.