trigger wheel coils

[art]

has anybody had to change the three trigger wheel pickup coils or had any trouble with them ? I am still having poping an low speed stumbling from my valk.I have desmogged it changed the wires an plugs,had the carbs cleaned,got new o rings for the intakes an all new vac. caps for the carbs.A dealer suggested that the coils may be breaking down after the bike gets up to operating temp.My pilots are adj.to 2 turns out an I synced the carbs.I have ordered new exhaust gaskets but have not got them yet.This has been going on for about a year.I have 100000 mi on the beast an it runs good above 4000 rpm. HELP .Art in Or.

[DFragn]

There are only 2 timing pickups on all models. Maybe that's your problem, but I doubt it.
 
I'd wait for your exhaust gasket install. Bad ones would cause the popping, but not the stumbling.

It's possible who ever did your carbs wasn't thorough enough.

It also maybe be good to check all six needle diaphragms under the carb covers for pin holes, seating or tears. Hard to tell how thorough they were with inspection/cleaning or creating damage accidentally. Diaphragm damage can cause stumbling.

I would also check the 1.5" vac hoses on the side of the carbs themselves for splits/cracks by manipulating them. These will cause stumbling too.

Just a few ideas. Hope it helps.

[Kingbee]

Since you mentioned your problems are at low speed, it's not the pick up coils.  My $$ is still on the low speed jets.

[Patrick]

Like the boys said,, your problem like varnished low jets.. Add a can of sea-foam to the fuel tank[well mixed] and go for ride.. Run at a speed that the bike starts to run good at and then start to slow down until it runs poorly.. Keep it there until it starts to clear up then slow down some more.. It may take a couple tanks..If that doesn't do it then its time to get your hands dirty and take the carburetors apart for a good cleaning.. As for the ignition system;; I'm not sure what the dealer is telling you.. The pulse generators live next to the trigger and there are two of these.. There are three ignition coils living under the fuel tank.. I seriously doubt you have an ignition problem.. Popping can be caused by defective vacuum lines and/or leaky exhaust gaskets..have you tried snugging-up the exhaust retainers??

[art]

I am going to replace the exhaust gaskets this weekend an keep my fingers crossed.I did change the little vac.hoses between the carbs

[Udo]

The ICM uses the voltage from the pickups, to trigger the sparks. If the peak voltage is under a given limit (0.7 Volt), the ICU will not generate a spark, and the engine will not run. So, popping / stumbling at low speed is not a indicator for bad pickups, imho.