Join Date: Jul 2011
Location: Cornwall, England
1986 VT1100c Ignition problems -Help!
Hi - I purchased my 1986 VT1100c a year ago with a duff gearbox (no third!) and various other mechanical & electrical issues. I've been working on it ever since. I've now rebuilt the gearbox (worthy of a 2nd post in itself!), and replaced/reconditioned many, many other components (probably worthy of several more posts!).
Bike now starts and is fully MOT'd. However, it will still only run on its rear cylinder (a problem that pre-dates my ownership) and the solution is still elluding me.
Both cylinders have been pressure tested and have virtually equal & good pressure.
Both coils are good as are all HT leads (excellent sparks from all 4 plugs & internal/external resistances well within spec).
Resistance on all 3 pulse generators is fine (Cam plus both crank) - although I've changed both crank units with known good ones to confirm).
Rectifier has been replaced and is working fine.
I've swapped out (and back) different sets of carbs and the problem remains the same with both (again, one is known good - both are VT1100c specific) - plenty of fuel getting to the plugs.
Timing position has been checked and confirmed OK against timing marks and also by having the front cylinder cover off to check physical valve positioning is correct against this).
Primary (A) CDI unit has been swapped out with known good unit.
Only other symptoms are that rt hand exhaust does occasionally backfire & you get occasional 'flashes/pops' of fuel ignition activity from the front carb - whilst the bike is running.
Bike starts fine from cold.
Any suggestions or inspirational ideas would be more than welcome/appreciated! I can now offer a source of spares, knowledge, advice, empathy, sympathy, etc. to any/all fellow Shadow owners who've experienced problems & needed to demonstrate particular determination to overcome them - and/or several cases of beer or bottles of wine to anyone who can help me over (what I really hope is my last) major hurdle before I can get back on the road!.