cutting out on one cylinder.

[johnD]

Hi all.
Have you missed me? What with the aphalling weather and a new project Ive not been out on the Kat much. Took it out and it started to miss a bit, put it down to needing a clearout. That got progressivly worst.
At startup, one cylinder would be cold, could be number one, or number two, seemed to alternate. As you would, (owning a Suzuki), I reached for the NGK catalogue and ordered up a set of, expensive, plugs.
A little better for a short while, then back to this erratic running. It could, of course, be the usual blocked jets, but not with these carbs. Looong story cut short. I eliminated all the usual suspects, scratched my head, then a clutch at straws, I replaced the plug caps with those I had ordered for the project. Yup, normal service resumed.
Now. The original plug caps have a resistor inside. Some of these caps are demountable, look for a slot in the plug connection to unscrew. Took mine apart and found a tensioning spring against the resistor, red rusty, as were the internals of the cap. She now starts and ticks over steady as a rock again.
These BS32 carbs have certainly proved their worth, even after standing for two months or more, she kicks up first push of the button, even with dud plug caps!

BTW, Ive been given a very sad looking VVT 400 Bandit, sandblasted the frame and tank, fully resprayed and finally assembled. Still jobs to do, but its first road test this week. Engine sounds very solid. These things are claimed to have 57 BHP..... we will see.
Cheers.

[Smallkat]

Of course we missed you! Especially your step-by-step carb swap (with photo's)! Hint, hint...

These old bikes love to keep us on our toes. Glad you got it sorted and imparted the knowledge on here so that when it is inevitably our turn, we know one more thing to check.

[johnr]

if youve removed the resistor caps, why not buy resistor plugs instead, theyre usually the same numbers as the ordinary plugs but with an 'r' added on the letters at the start.

[johnD]

Hi John (et. al.)
Seems that all the plugs I have looked at are resistor plugs anyway. But, this is the reason i hate wasted spark ignitions with a vengence. Consider. One coil winding is split between two plugs. Should one plug have a high resistance, bad lead, fouled plug or as in my case, high resistance plug cap, the ignition spark will take the least line of resistance, through the good plug/lead/cap. Makes it very hard for the duff cylinder to clear itself if the spark is weak or non existant.... especially at low, or, surprise, startup revs.
A seperate coil per cyclinder would obviate this, but.... would cost more and need space to fit. a proper seperate ignition pulse/coil per cylinder is the optimum ignition system, but the cost accountants would commit Hari Kiri.
(Those unreliable Italian Aprilias actually DO use this method.... Never miss a beat.)
Cheers all, finally some sunshine, down to Barton tonight for a mooch and an inedilble cheeseburger n' chips.