Single cylinder TWIN!

Any ideas please? My pal in North Yorkshire has a Spada 1000 1989ish and it refuses to fire on the nearside / left hand side cylinder. After tearing his hair out he has swapped, coils etc and carbs but it refuses to fire. Compression OK, Timing OK checked using a disc on the front. I would nip round with my colourtune but as he is three and a half hours away I need some ideas please before I do please. Thirsk dealer unable to advise, no one old enough apparently. :question:

What was the last thing he did to it is usually a good place to start. Has he ever had it running?
Then check the timing is on the right cylinder. It would probably fire up on the right if timed on the left timing mark, but not on the left.
What ignition system does it have fitted? Is he getting a spark on the left? Are the points opening and assembled correctly?

Bought as a running engine from a damaged bike but not heard before purchase. I’ll ask about ignition system, points and which cylinder it was timed on. Thanks.
P.S. Standard ignition and points and Roger says he has timed it on both cylinders.
I am at a complete loss so am not much help to Roger who is not your average mechanic as an ex Lotus man and also runs an early Morgan three-wheeler he’s had since he was nineteen. Brain wracking required please.
Thanks again.

Check for a spark on both sides so you can narrow it down to ignition or fuel issues.
Assembling the points wrongly is a good one to catch people out. As is leaving a piece of rag up the inlet manifold after doing a rebuild(guess how I know that one!)

Thank you, I have passed on all the info. Let’s hope he cures it soon.

There are lots of dodgy plugs around, but:
Does it run on Easy Start spray? Might eliminate/confirm fuel or ignition.
Has he done basic checks with a voltmeter to check low tension circuit is wired up OK?

Please keep them coming, all passed on to Roger.
The engine is under a cover on the bench now whilst he fits a kitchen but news as it breaks will be passed on.
Thanks again

Contact breaker or condenser not working. Condenser may be missing/ broken/ duff. Each Condenser is attached to timing unit by a screw, and is also an electrical connection, screw could be loose or missing or bad contact, dirt rust etc. Must be clean metal to metal. Contact breaker not opening or wire shorted to ground. Or wire open-circuit. While the contact breaker faces have a reputation for being splendidly long lived, the heels that ride on the cam are not. When badly worn, breaker won’t open cleanly so may not make a spark or a poor spark and timing is all over the place. Guess how I know.


Thank you for the ideas HTH.

HTH is not my initials or “handle”, means “Hope This Helps” :smiley:

Doh! In that case IHIH. :laughing:

Did you swap the carb from one side to the other to see if it went from one side to the other same with the coils and plugs as well happened on my G5 mind only one thing at a time check for air leaks on carbs hope it works if not strip those carbs down there more parts than you think all the best Derek .

Thank you Derek,
Yes that’s the strange thing, swap everything and the same firing cylinder still works but the non firing cylinder still does not fire.
I know Roger is up to his eyes with clock work until Xmas and he intends to have a tearing down session over the Xmas season. I am sending him all the answers as they come in.
All the best

Cured: First problem - dodgy compression tester. New compression test showed almost no compression; head off exhaust valve culprit and aided by a broken piston ring.
Thank you for all your ideas.

Good to hear you’ve got it sorted.

Well that explains a lot!

“Bought as a running engine” well patently not!!!

You don’t just get a broken piston ring just like that, what actually happened? There may be other damage. the cylinder liner could be fooked, there was a time you could have them rebored, not sure now or whether oversize pistons are available any more. :frowning:

Hell! I’ll pass that on. The vendor did offer to change the engine though.

I’d not had my Spada very long when it had a partial seizure going up the M6. (Actual cause is a very long story.) Extraordinary amount of damage.
A rebore wasn’t going to be a permanent solution because the liner was also cracked, not just scored. Also a problem finding oversize piston rings that would fit. In the end it needed a complete new (nikasil) barrel and piston kit. Very expensive mishap. BUT at least in those days (1982 I think) you could buy the new parts easily.