Perplexing 85 VT 1100

[Snow Shadow]

I recently acquired the bike to fix up over the winter. Here's the problem. the bike starts fine but only fires on the rear cylinder untill the temp comes up. Then the front pops a few times and seems to run fine after that. Some history to rule out other causes-New plugs-Replaced spark box-Coils tested good-Carbs cleaned and are good-Plugs removed and plenty of spark. The unusual thing that I've found is that if I partially remove the spark plug cap just enoph from the plug to cause an ark, while the bike is warming up. The front cylinder will fire properly. It doesn't matter which side I do this to. Any Ideas its got me a little baffled.

[93gc40]

Start by acttually testing the ignition components with a VOM, as per the instructions in your manual. Sound like bad SP wires at the least. Next verify that the carbs are set to the correct INITIAL adjustments. More adjusting may be required after warm-up. Is the Gas fresh? Is the battery Strong, having 12 volts is only a partial answer.

[Snow Shadow]

The battery is new and I have tested all that I can with a VOM Coils & pulse generators.
Ive set the air fuel at several different setting from 2-4 turns out to see if it made any difference it did not seem to. Im going to try new plug wires next Any suggestions on the best type of wires to replace them with, And thank you very much for the reply.

[93gc40]

Could just be a stuck or out of adjustment float valve. Could be bad plug or plug wire connector. Could be out of adjustment choke. Just for giggles have you tried swaping the coils? Could be the carbs are way out of sinc. Especially if they were seperated during cleaning. Where the pilots and chokes removed for cleaning. Could be leaking intake boots. Could be leaking slide diaphrams. Leak could be pin holes or tears or it just didn't seat right, in the grove. New battery, does not mean its a fully charged battery or garantee its good.

[John Hopkins]

Sticky valve??

have you tried a compression test to compare cylinders.

150psi would be nice.

John.

[Snow Shadow]

Compression is good - Carbs have been cinched- Runs excellent when its warmed up. Only missus when first started,

[number13]

Either bad spark plug wires or bad Sp caps. Replace them all.

[PainterD]

Check the coils over with a fine tooth comb. They've been known to crack (real fine crack) causing them to expand when warmed up, and contract when cooled off, which causes all kinds of headaches. Just sayin'.