Cylinders 1 & 2 not firing.

[signart]

Looking for any connections or reason no. 1 & 2 cylinders won't fire on start up. When last run, it ran good but developed a flat spot on acceleration and continually got some worse, but ran well on harder throttle. Set for a few days, now this.
Where I am looking: removed tank, plugged #3 vacuum, direct line to remote tank, eliminating petcock.
Carefully inspected vac lines & manifold caps.
Any ideas where to look next?

[Patrick]

Have you checked for spark at either cylinder ? The front coil runs cylinders 1 and 2.

[signart]

Doh!
Good call Patrick. Went to check fire on 1&2, but inspected coil first and the black/white wire connecter to coil was off. Now firing on six.
Have to install tank and fuel up to see if it remedied my flat spot.

Thanks for being so quick on the draw, and accurate.

[signart]

Starts and idles very well, but not going to put tank back on just yet.  Not very smooth from idle to two thousand rpm. High revs feels strong.  If I hold it at 1500, flutters and burbles a bit. Dumped some Berrymans in the remote tank setup. Been letting it run with squirrel cage fan in front of radiator. Will see if that clears anything up.

[salty1]

Obviously, you may have to pull the carb bank. Also, when is the last time the plugs were changed?

[Patrick]

Well, I'm not sure I'd worry too much about it right now unless it runs really bad. I'd stick the tank back on being careful to not kink the vent line and run a couple tanks of heavy doses of Sea-Foam [full can each tank full] thru it and see if it clears up.

[signart]

It's just that my back-up Valk ('97) throttles up from idle like an electric motor. This, my main Valk ('98) is stumbling just about where you need to release the clutch from a stop, possibly resulting in a stall. I've got all cylinders firing and could ride it, but it looks like gonna have to pull the carb bank to get it where the '97 is before I sell it.

Thanks for all the input and the help getting it to fire on all cylinders.

[salty1]

Sure sounds like the slow speed jets are filling with crud.

[signart]

Going in. ???

[signart]

I have everything disconnected and ready to pull carb bank and last thing I disassembled was my velocity stacks off left side. I was inspecting needles as I go and discovered the vacuum diaphragm torn on top of carb #1. This could be my low rpm problem?
Another problem is quick search on parts availability shows upwards of $90 each! Can the rubber diaphragm be bought separately anywhere?
I hope I don't find anymore of these torn.

[9Ball]

you can buy a set of carbs off a wrecked bike and take your chances that the diaphragms are intact...but if only one is damaged I'd just spend the money on a new one.

they're only $72.04 each thru HDL   

018 PISTON, VACUUM
16111-MZ0-A00  006  $92.12 $72.04

[Patrick]

That tear could very well be your problem. Expensive little critters aren't they !

[signart]

Why I didn't pull these stacks first and find this before I have everything ready to pull carb bank out. I like to do the easy stuff last, I guess. Someday I'll learn.

Expensive and expensive to ship. The better the prices on these, the higher the shipping. Couldn't weigh more than a couple ounces +$17-$21 shipping.