Assembly completed but won't start. As far as I can see valve timing is correct, engine "feels" OK to the kickstarter (seems to compress OK), spark at both plugs (electronic ignition), timing correct to the marks, new carb floats/jets, etc. but no joy, just the occasional random bang. Even tried taking the silencers off. Probably something silly but can't fathom out what at the moment. Any off the wall thoughts welcome!

If your getting the occasional bang, then the timing is out. could be as much as 180 degrees..

Did you use the crank locating tool or just spin the crank until the timing mark lined up on the rotor?

Also what EI is it? I know with the Trispark, you have to align it as per the instructions then rotate the timing plate clockwise (key switched on) until the light goes out. if the light doesn't go out then you need to reposition the rotor so that it can.

With any EI, check the magnets on the rotor can hold its own weight off a spanner, if one magnet is weak, the motor won't run.

Thanks. It's a Wassell set, it's new so I think rotor megnetism should be OK. I understand it's a wasted spark system so can't be "wrong cylinder" as it were. Has 6V coils and sparks on both plugs. It's timed to the timing mark on the alternator rotor, have checked piston position vs timing mark which seems (loosely) correct i.e. fairly close to the top of the stroke, but not done vs crank locating tool. I guess that's next!  Thanks   

Something as simple as swapping the HT leads round maybe?

Quote from: wardy on 02 October, 2023, 11:30:03
Thanks. It's a Wassell set, it's new so I think rotor megnetism should be OK. I understand it's a wasted spark system so can't be "wrong cylinder" as it were. Has 6V coils and sparks on both plugs. It's timed to the timing mark on the alternator rotor, have checked piston position vs timing mark which seems (loosely) correct i.e. fairly close to the top of the stroke, but not done vs crank locating tool. I guess that's next!  Thanks   

If your using the mark off the alternator only, its posisible that your other mark is after TDC, which would work with the backfire in the exhaust.

I would still check the rotor though. I had a brand new Boyer have this issue.

Another thing to check is the black-white and black-yellow wires are going to the right ones, as the ignition will retard instead of advancing.

Also ensure you have a dedicated wire from where the red on the black box goes to the coil, back to the battery positive. Also ensure your coils are wired in series, not in parallel.

But yes, crank locking tool is the best way, it keeps the crank locked whilst your setting it all up, it can easily drift off timing when screwing the rotor allen screw tight.

FYI regarding locking crank for timing in case you haven't already got the info.

is there fuel on the plugs?
i had the same thing and it was a poor , sticking float and needle.

Thanks all for your help. Have checked the flywheel timing slot which is perfectly aligned with the one on the alternator rotor. Sparks on both plugs, wires correctly connected and it's a wasted spark system anyway. Tried squirting some fuel down the intakes which provoked a better response so I'm on the "fuel system" tack this weekend now. Fingers crossed!

electronic ignition is good but the pick up rotor gap has to be spot on to fire correctly or at all. if the correct gap is 0.03mm for example, then i also set the plug gaps to that clearance.
unless the pilot jet is blocked it should fire up.
another thing to look out for is a slipping clutch. you may be turning the engine over too slowly to fire even though your kicking madly.

I don't know if you saw my recent thread on poor starting but I found that over rated resistor caps were an issue. That and a new coil that lasted 4 miles! I had success by putting unresisted caps on.
I would check the power getting to your electronic box with a bright bulb, brake light or similar, better than a volt meter as it puts the supply under load so if the bulb flickers or is dim you know where the problem is. I would not assume the pilot jet is clear even on a new carb. I've have read countless threads finding blockages in new Amals in the past. Not sure if it's still a problem.
just to state the b&%$£ing obvious, I imagine your battery is up to 12.7ish volts. My Vape ignition (Wassel) is great but does not suffer weak batteries and that you are tickling the carb till petrol comes out.
Good luck, I know how frustrating this can be!
Cheers Glenn