1986 honda cbx250rs sparking too quickly

[Speedracer]

Bike was working fine, then it would only push start (won't start on the starter) so I've taken the plug out and it's definitely sparking a lot faster than it should (starting on the starter) as if it was a 2 stroke not a 4 (At least twice as fast as it should).

Before I checked the plug I shoved a lot of engine start in and it eventually let off a terrific **BANG** out the airbox and the bike briefly caught fire (a few times lol) So it could have a weak spark as well if that helps...

I also hooked up a car battery to it which made it turn over a lot faster but this didn't fix the problem???

Anyone got any ideas where I should start looking?

[kevfromcoro]

Anyone got any ideas where I should start looking?
[/QUOTE]

For a fire extenquisher....1st..

[Squiggles]

I expect you'll find the engine has no idea whether its at the end of the compression stroke or the exhaust stroke, so sparks at both... (either that or i completely misread previous posts)

[xwhatsit]

Bike was working fine, then it would only push start (won't start on the starter) so I've taken the plug out and it's definitely sparking a lot faster than it should (starting on the starter) as if it was a 2 stroke not a 4 (At least twice as fast as it should).

Before I checked the plug I shoved a lot of engine start in and it eventually let off a terrific **BANG** out the airbox and the bike briefly caught fire (a few times lol) So it could have a weak spark as well if that helps...

I also hooked up a car battery to it which made it turn over a lot faster but this didn't fix the problem???

Anyone got any ideas where I should start looking?

It's what's called a `wasted spark' ignition system. It's supposed to do that; the pulser is on the end of the crank, not running at cam speeds, so it sparks on the other rotation too. Doesn't hurt it at all, I've seen certain literature claim it helps clean the spark too, but I don't know about that. Probably just done because it's simpler and lighter and less likely to go wrong.

Dunno about your starting problem; if it will still start by push starting it, maybe it's just a matter of a weak battery system (i.e. you're using all the juice turning it over with the electric start, there's nowt left for the ignition system). But then you say even hooking up a car battery to it didn't get it going, despite having enough juice to turn it over even faster. Got a workshop manual? Perhaps do all the alternator tests etc. The RFVC 250s are supposed to be reasonably resilient despite top end problems, don't hear much about electrics. But then again most of them were kickstart, not electric start.

[Speedracer]

Cheers guys
Might try concentrating on the weak spark bit then.