HELP - Something's gone awry

[Vegan]

I've had my NC30 for a week now - today it was running fine - all of a sudden, after stopping at a light, I pull away and the acceleration felt laboured, I figured I had miscounted my gears - but no - I was in first. I also noticed the sound change - it sounds as though it is not running on all cylinders or something. It's not overheating, but it's not firing up properly now either. FUCK....any clues?

[DingDong]

forgive my ignorance... is NC30 a 2 stroke? if so check the fuel mixture... if its a 4 stroke check the plugs for unburnt fuel (and spark) or check the carbs

[FROSTY:Me]

some theiving streetkid stole 2 cylinders whilst ya was at the lights.
I'd check plug leads and caps.drain the carbs in case its sucked a lungfull of water and whilst in there just check just in case one plug has loosened off.
deeper in than that and youre gonna hafta call an expert

[Gremlin]

I don't want to sound obvious, but you aren't low on fuel are you??

Do you have a reserve tap??

[Vegan]

Yeah - checked the fuel - still a decent amount in there and only done 80km on the tank so far I think.....has a reserve tap yes - what seems to be happening is this. I leave the bike for an hour - start it up - runs ok....running normal I think, then after about 2 mins it decides to run all f@#ked again.....then when i get on the clutch, the revs drop and it cuts out (even with choke on). Thankfully I actually made it home....Battery is also dying on it...charge drops right off.

It's as though something heats up and then fails? - leads? I don't really know anything about bikes so I guess i'll be taking it to someone who knows something.

[HDTboy]

Sounds like you may have a dodgy coil, I'm not sure how they're set up on NC30s.

Freezing the coils (in the freezer) sometimes works as a temporary fix for cars

[Vegan]

How about the spark unit or pulse generator? Reading the trouble shooting guide atm..... feck it - the shop can deal with it - I can only hope it doesn't cost me a bomb

[Vegan]

Or the rectifier - ? the more I read the more likely it seems to be the battery or rectifier....

[sAsLEX]

run it for ya two minutes or however long it takes to run shitty then compare the temps of the headers either with careful application of fingers or a fancy infrared thermometer

this will isolate cylinders if its just one or two bung, or if they are all the same temp then it could be reg/rec

but i would be looking at sparkplugs first off, you get them cheaper at repco than the bikes shops as well

[wendigo]

Yeah - checked the fuel - still a decent amount in there and only done 80km on the tank so far I think.....has a reserve tap yes - what seems to be happening is this. I leave the bike for an hour - start it up - runs ok....running normal I think, then after about 2 mins it decides to run all f@#ked again.....then when i get on the clutch, the revs drop and it cuts out (even with choke on). Thankfully I actually made it home....Battery is also dying on it...charge drops right off.

It's as though something heats up and then fails? - leads? I don't really know anything about bikes so I guess i'll be taking it to someone who knows something.

Sounds like the regulator/rectifier unit is toast ( or possibly the alternator is going).

The fact that the bike starts ok after an hour gives the impression that the battery has had some time to build up residual charge so it runs fine for a short while. As soon as this charge is used up it, bike starts misfiring.

Things I'd try:
1. Turn the lights of (if your using them & if you can) - if it runs better /longer before misfiring you know the problem is electrical. Conversly flick the headlights onto high beam at idle & see if it dies.
2. Charge up the battery - I'd the same sort of behavioutr on an NC23. What I found (among other things - see later) was that the electrical power output from the alternator & the amount of power used by the system didn't break even 'till about 4-5000 revs. Hence pootling around in traffic at low revs caused the battery to slowly discharge itself.
3. If the battery is old & doesn't hold its charge, biff it.
4. Check for loose connectors & that the connections are good.


Give those a try and let us know how you get on. Hopefully that will do the trick & if so do, not read any further.


If the above doesn't work, my money is on the regulator/rectifier unit for your present problems. I'd a grey import CBR400RR. Within a month of buying, it the regulator rectifier unit went (the give away was when I stopped at a traffick lights & was enveloped by the stench of rotten eggs. The battery was getting cooked). Went in & got the rectifier replaced under warrenty. At the time I was told that the regulator/rectifier unit was the bug bear of the CBRs. Don't know if this was true or not but it certainly happened to me. I went through about 1 regulator/rectifier unit per year after that. This time the symptoms were pretty much as you describe. Driving along, suddenly misfiring, battery flat as & again the occasional wiff of rotten eggs - this time from the unit itself. Fortunately when the aftermarket units went they burned themselves up as opposed to cooking the battery up as well. This continued for about 4 years until eventually the alternator blew. Went to the local breakers where they had several rewound alternators. It solved all my electrical problems. Not only did I stop blowing reg/rect units like clockwork, but it also solved the problems I was having in point (2) above. Moral of the story? Ultimately my problems where caused by the alternator, not the regulator/rectifier.

[Vegan]

Thanks for the help guys - appreciate it. Today the battery DID die much faster - I put the lights on....but then the residual charge is less and less each time I start it...so, either the battery is F#$Ked or it's not being charged I guess. So i've bought a new battery. Can anyone recommend where to take the bike to have the autoelectrics checked?

[vifferman]

Can anyone recommend where to take the bike to have the autoelectrics checked?

Depends where you are. It's easy enough to check, if you know what you're doing. Someone like Kerry at Motohaus can sort you out, or alternatively some KBer with a multimeter could diagnose it for you.

[wendigo]

Can anyone recommend where to take the bike to have the autoelectrics checked?

Sorry, can't help you there.

What I would recommend is to get yourself a Haynes manual (http://www.haynes.co.uk/webapp/wcs/s...3507&langId=-1) and a voltmeter & do it yourself. As vifferman says it's pretty simple & it'll save yourself money pretty much straight of.

Can you get your hands on a multimeter ? If so check this out
http://www.vsource.org/VFR-RVF_files/Bvfr400r-mi.htm

About 3/4 of the way down the page
->"Reg/rec regulated voltage/amperage 13.5-15.5v (0-6A) @ 5,000rpm"

so
(1) wip the seat of (I'm assuming here that the battery is held under the seat)
(2) attach the voltmeter across the terminals of the battery
(3) note the voltage of the battery with all the bike electrics turned of. If the battery is in good nick & fully charged it'll be in the region of high 12ves to low 13 volts
(4) turn on the ignition, note the voltage again, then start the bike.

If the voltage reading is higher with the engine going than when the ignition is turned of the battery is charging, else it is discharging.

(5) rev the bike up to 5k & see if the voltage is within the given range. If it's wildly above it, you're toasting the battery & the reg/rectifier at least is munted. However my guess is that the voltage will be below that given. If so , the good news is that you're old battery might not be totally fucked. The bad news is again you've got problems with the reg/rectifier/alternator.

The final thing to check is that you don't have something shorting out & sucking excessive power out of the system. If something is shorting, the voltages read are goingto be lower than expected. To test this:
Turn the ignition of, switch your multimeter to read amps (and tens of amps at that, NOT milliamps - get this setting wrong and you'll be buying yourself a new multimeter), and attach the multimeter inline with one of the terminals. If the the reading is not 0 amps, something is shorting. Make sure the lights are of & switch on the ignition (DO NOT START THE BIKE - if you do, with the multimeter still attached , you'll probably cook it). If the power draw is excessive (I seem to remember the CBR using ~1 amp with just the ignition on & no lights, though don't quote me on it & I can't imagion a VFR being much different), again your charging sub-sytem is probably ok & you have problems elsewhere.

Then again, after all that writing I see I've forgotten to point out the obvious. Firstly, have a look at the regulator/rectifier unit. If there are any signs of soot or burning, its munted. Also sniff it. Generally when electronic components burn out you get a healthy burnt metal/plastic & rotten eggs smell.

[Vegan]

LOL (i'd rather the battery be the only thing that IS fucked since it's only $50to replace ) - I'll try this out - problem is - My pillion seat is stuck on - does it matter? Or can i slide the fairings off the rear with the pillion still attached? (Ie - remove the 6 bolts and unplug the rear lights). Cheers for the help guys.

[wendigo]

LOL (i'd rather the battery be the only thing that IS fucked since it's only $50to replace ) - I'll try this out - problem is - My pillion seat is stuck on - does it matter? Or can i slide the fairings off the rear with the pillion still attached? (Ie - remove the 6 bolts and unplug the rear lights). Cheers for the help guys.

Whats the seat stuck on with?