Dead CBR250

[Trow]

Help!

My partners 1989 CBR250R died today on the motorway, when she came to a halt the start button didn't work but things like horn lights etc did, so - Changed the 10amp fuse for the ignition , got it to turn over but it just blew the fuse again... is there a common fault anyone knows about that I can check e.g. CDI unit ??

Thanks

[crazybigal]

my brothers bike was doing this, turned out to be wires worn and shorting to earth, headlight wires! you wouldnt think it would do it.
so check over all the bikes wiring even the stuff that is inside the plastic sheath.
otherwise it could be a number of things, i dont think the cdi would have anything to do with it. if you have a multi meter check your batt voltage and the charging circuit
good luck!!

[Postie]

as crazybigal said, one of your wires somewhere in there is shorting the system. If you can't find it easily, like a loose earth wire mounting point for example. Take it to a sparky to save your time and swears.

[Trow]

Yeh it might be worth taking to a sparky as you said! it could be a lot of hair pulling and teeth grinding

[surfer]

How good are you with the elctrickery stuff and do you want to learn?

You sound like you have a melted wire or earthing connection.

Basically get a volt meter and start at one end of the wiring loom and work you way through it to the other. Put the voltmeter to check for current going through. Start with the part of the wiring loom that has the blown fuse. You will need the wiring diagram which will either be in your manual or you could probably get one off the internet. Best to get one that is printed in colour as this will be easier to follow.

When you get to the fault bit you may find that you have a bad connection which is earthing to the frame or melted wires inside the wiring loom in which case it is easy enough to replace them by cutting them out and replacing them with equivalent wire, make sure you do a mechanical join as well as a solder. Cover with heat shrink on the join. Then recover the that part of the wiring loom with heat shrink as well.

Typical places to look for dodgy wiring are where the wiring loom has rubbed against another part on the bike and it has become frayed and opened up. Like under your tank or seat. You might first try a visual inspection and then a double check with your volt meter.

Enjoy and good luck.
.

[Fatjim]

Any news bro?

You got a multimeter btw?

[Trow]

Hey thanks surfer! sounds good.

Here's an update to my troubles

I removed all the fairings and tank to start testing the loom, what I did was disconnected the generator to test for continuity (to see if there was a dead short in the windings) and found nothing so I though well I will replace the fuse and turn over the engine to see if it blows again which would tell me if the gen was at fault. Engine turned over fine!! so I thought to prove that I would connect it up again and see if it blows the fuse! NO! instead, the bike started and purred away like a cat.. at this point I stood back and scratched my noggin in confusion!

Whilst the bike was running (on carb fuel only) I furiously wiggled the loom to try to get it to go to ground but nothing happened.

At this point I thought I would fire it back together and take a short run around the block, so got the tank on and connected (all the time starting it to see if the problem came back) eventually though the bike lost power and died. I tried to restart but nothing so pulled a fuel line of and found it dry.. no fuel! At that point the battery was quite low from my persistence to make it go so removed the battery and charged it up. When I put it back on I tried to start it again so hit the button, it turned the engine once and blew the fuse! AAARRRGGGHHHH!!!

so to my guessing the most probable root cause must be a intermittently faulty fuel pump, not running and shorting out.. so instead of drinking myself stupid tonight as I should be, I will be removing the fuel pump and testing it on the bench, I await the sparks and hot anger with baited breath!!

I will update soon as to my adventures in electrikkery land

[NinjaNanna]

After becoming a human marshmellow trying to light a pile of greenery with petrol on saturday, make sure you are careful about sparks and fuel vapours.

I knew I needed to be careful but I totally underestimated the danger of the fumes. When I lit the match I became totally engulfed by the fireball, luckly I escaped with only singed hair and a sightly burnt nose. VERY LUCKY

By the way have you got the electrical diagram for your bike? If you do I can probably help you out if you need it

Cheers

NN

[Trow]

yeh, I am on holiday now and promised myself to remove the pump and test it but, I am procastinating badly in fear of losing my eyebrows!!!

I may need to call on your help mate, I do have a wiring diagram but it doesn't have the wire colours on it :-(

If the pump is not the problem then it must be heat related as the bike didn't die again until it was hot.... if that's the case, I have no idea where I would start!!

ahh well, suppose I should don my coveralls and attempt to test the pump.... update soon..

[Trow]

O.k, found the problem.

Looks like the fuel pump was the culprit!! I removed it today and tested it to no avail - she no run !!

will have to find a fuel pump now, will give the dealership a call tomorrow... phew, might have my partners bike ready for the holiday blasts!