Why doent the bike run after an impact?

[bobsdevilishgrin]

I recently came home to find my 1989 CB1 laying on its side. Came to find out the landlords sister hit it with her car, aside from the obvious plastic damage, the bike will start, but when I give it gas it will not accelerate. Instead it sounds like its running out of gas, and will quit as long as I keep throttling it. If I let off the throttle it will resume idling. I think the fuel pump is damaged but I dont want to replace it if its something like a dead man switch or if there is a fuel cutoff relay or sensor somewhere. I have attempted to look these parts up on OEM sites but have not been able to find them anywhere. Cn someone please help??? I love my CB1 and have waited out the winter to ride, and now that spring is here I cannot ride!

[pinpoint]

Sorry to hear that mate

Could be the fuel cut-off relay - which is a mysterious small black wiring box under the left cover. It stops power to the fuel pump in case of accidents.

Mine was tripped when I cleaned out all fuel traces - I had to bypass the pump with gravity-fed carbs before it would turn the power back on again to the fuel pump. Maybe try that? Just connect the fuel pipe straight from the tank to the filter, to the carbs. Then, after a while, try hooking up the pump again.

This will let you ride around (the bike doesn't really need the pump) and if you keep having the same problems you can know for sure that it's not the fuel pump!

Cheers,

PS - My pump isn't working either at the moment, but the wires giving it power read 12v with ignion switch on. And the pump itself works when hooked up directly to the battery - any help on why/how to fix much appreciated!

[clarkdw]

Pump only pumps when there is spark ie: engine running or turning over. After you run the bike out of fuel it is usually a supreme beotch trying to get the carbs full again before killing the battery. That is why your trick of bypassing the pump helps. It will only run without the pump if you keep the tank somewhere above half a tank.

The fuel cutoff relay is not like a tipover switch. It is not related to the attitude of the bike nor is it related to impact. It only allows the pump to run if the engine is running or sparking while trying to start.

You may have disturbed some junk in the float bowls and blocked some passages in the carbs.

[pinpoint]

Thanks!

I guess those little black boxes are not so mysterious after all. I knew someone here would know!

Sorry for being thick, but why would the wires to the pump show 12v when the engine isn't ticking over? (i.e. the ignition switch is on, but I'm not touching the starter button).

Don't know if it's relevant, but when I hit the start button the voltage drops on those connectors to about 9v...if that makes any difference. And when I do hit the start button (with the pump attached) it doesn't shoot out fuel - (even though I know the pump itself works fine).

[bobsdevilishgrin]

Well, I managed to get it going today after I realized I had taken out the air cleaner plate to get it replaced a while back. (before it was hit) Then I ordered one from a local bike shop and they sent me a cone filter for a single carb. Needless to say, I couldnt use it and never got back over to reorder the proper air cleaner and never put the old one back in. So I tried that today and what do you know, it ran fine. On the topic you were asking about the voltage drop, if you were saying that the voltage dropped to 9 volts while you were cranking it thats normal due to the starter drawing more current. Also in the case of many electrical devices it simply draws more current to start the electrical device than it does once its running. And with that something I noticed after I got mine running that the pump wasnt steadily putting fuel into the filter, rather it was surging every couple seconds into it. Dunno if that helps or not, but thanks for the replies to my query.