So had the NSR at a local race day. Ran it hard for the first two races (didn't do all that well but that wasn't the bikes fault) but with 5 mins to go before the final race, the dam thing wouldnt start.

Got it to run for about 10 secs with a few revs, but it died when I let it go to idle. Gave up on the race and packed up.

Today I removed the tank, drained the carbs, cleaned the plugs and put it back together. Choked it and kicked it over and it ran. Let the choke off down to idle and it died. Repeated the proceedure but no luck at all.

Battery seems fine as servo on turns with the ignition.

Anyone care to give an opinion on what is going on? It has done plenty of running with no setup changes (apart from new head gaskets last week) so I'm perplexed.

Had the same at a race years back and it was the battery. Despite the servo moving did you put the battery on the charger??

racer38 wrote:Had the same at a race years back and it was the battery. Despite the servo moving did you put the battery on the charger??

Just tested the battery and it is showing 9.2v. Have put it on the charger and will report back the result when it is fully charged.

You've lost at least one cell at 9V so just replace it.

nxrsr20 wrote:You've lost at least one cell at 9V so just replace it.

I suspected something strange like that, seeing it was running fairly hard and should have been charged fully. Is a faulty battery a likely cause of my problems?

Pretty annoying having a fairly new battery crap out though.

If it is a cheap chinese battery, then no surprise that I new one would pack it in. It could be anything from sulfated plates to loose internal connection. Hopefully you haven't thrown out the receipt and you can get an exchange.

The incorrect battery voltage can make the bike do all sorts of strange things.

nxrsr20 wrote:If it is a cheap chinese battery, then no surprise that I new one would pack it in. It could be anything from sulfated plates to loose internal connection. Hopefully you haven't thrown out the receipt and you can get an exchange.

The incorrect battery voltage can make the bike do all sorts of strange things.

It's a Motobatt one. Had it a year but only 30 odd hours of use. Regular starting but occasional periods of no use.

Anyway, I should probably look at a new one. Will change it over with a friends one and check the results.

Best you investigate your charging circuit. The motobatt batteries are very durable even in complete loss systems (my experience so far...)

greggo wrote:Best you investigate your charging circuit. The motobatt batteries are very durable even in complete loss systems (my experience so far...)

That's what I have been told. I'll do a test to check the regulator etc. Otherwise I'll whip the carbs apart and give them a clean and report my progress (if any).

motobat batteries are prone to faults, we ran them at work for a while and the shop would have replacements waiting for when I came in with a problem one

paul wrote:motobat batteries are prone to faults, we ran them at work for a while and the shop would have replacements waiting for when I came in with a problem one

This is the Paul from KOR on sunday right? If so, you know how I mentioned the NSR hadn't missed a beat so far...?

Anyway, that's interesting. There seems to be a bit of disagreement about these batteries. What would you suggest instead?

If the bike starts and runs fine on the choke I would clean and check the jets as you mentioned if it dies as soon as the choke is off. Sounds like a blocked jet/jets to me.

Or maybe an air intake between carbs and cylinders?
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Start with the charging circuit before getting your hands dirty in the carbs (not that what you are planning in there will do any harm).

First cause is the flat battery, checking the charging circuit will tell you if it was faulty or not. Hondas reg/rec units from this era are known to be a bit dodgy (ask anyone with a honda 400 - I went through 3 or 4 personally).

If the battery is simply co-incidence you might also have an issue elsewhere - but I very much doubt it.

If you want to go all gucci on the battery, get a gel one.

yeh, its me

there is some mixed info but I can tell you that last year I returned about 30% of the batteries we used, kept getting new ones for free so no big drama

yuasa are the best acording to my mate whos a auto sparky