Topic: Firing on 2 cylinders after rebuild

[Gavin]

Hi All

Well, after toasting my own success at rebuilding my 550 engine (after a dog broke off and jammed the transmission), I now realise I may have been too hasty.

Whe I fire her up, which is taking a few more kicks than normal, but it does need a new battery. She only runs on cylinders 2&3.

I've taken a peek at the points and only the points for those cylinders are firing. So before I start taking bits apart, can anyone give me a few obvious checks or parts to inspect.

My thinking is that possibly a coil has blown. Failing that it's time to start re-wiring or something.

Cheers

Gav

[Cvillechopper]

I'd make sure your connections are good for the leads from the points for 1 & 4 to the coil.  There are 2.  One connection somewhere just behind the right hand side of the engine probably behind the side cover or close to there.  The other is at the coil.  Also check the ground for that coil.  If this doesn't work, switch the leads on the coils and see if 1&4 file and 2&3 don't.  That'll tell you if it's the coil or not. 

Good luck.

James

[Gavin]

Good advice, thanks for that mate. I'll see if I can isolate the issue that way 

[750goes]

check continuity from coils to points - check plug leads and caps for good contacts..

[TwoTired]

If it has been a while since the bike ran, the 1-4 points could have oxidized and no longer carry current.  File the point conrtacts, reset the gap and static timing.  If you have a voltmeter, you should have voltage across open points and zero volts when they are closed. (Key switch and run switch on, of course.

Cheers,

[Gavin]

Tried poking at everything with a voltmeter yesterday. Even got the Haynes manual out too!

No spark or voltage from the points feeding cylinders 1-4. I've ordered up a NOS Honda coil and will try dropping that into the beast to see if that cures it.

I've just got a new battery too as the old one (only 3 months old) seems to have failed. Was thinking I might order up a new pattern-part regulator/rectifyer too as a new Varta battery and possibly a coil failing so quickly seem a bit suspicious to me.

Alas I can't get the plugs out to check that fuel's getting into cylinders 1&4 (plug spanner also on order) but running attempting to start with just those cylinders connected does produce a backfire so I'm guessing something's going on in there!