RVF fuel and battery problems

[mamak]

I had a little problem on my way home this morning. My RVF started stuttering and died on me. It was as if their wasn't any fuel. However the tank was more than half full. I switched the ignition off and started the bike again, it ran fine after that.
Is there any thing small that could cause this? I'd hate for it to reoccur but I dont want to start off by taking the bike apart to find that it was an easily solved problem.
The other thing is my battery keeps running down. I've changed the battery and checked the charge voltage while the bike is running and it's fine, this rules out the rectifier and the alternator. I cant find any short circuits either.. However all the sources I've read(Haynes manual and internet) say this measurement should be performed with the engine revving at above 5000rpm. Now what I'd like to know is that does the battery only get charged at 5000rpm and higher? It would explain why my battery is running down as I've been doing mostly city riding lately.
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sliding by the seat of my pants. OUCH!!!

[EuropeanNC30R...]

Funnily enough, recently I've had very similar the fuel and battery problems like you've had on my VFR400 nc30.

Fuel:
When it happened to me I actually had to walk to the garage to get some more petrol, even though the tank was half full. I'ts been said on 400greybike that when the fuel level in the tank gets a bit low, it can expose a problem caused by a weak vacuum and thus the carbs can't get enough fuel.

Firstly check the vacuum hose is connected to the fuel tap correctly, and that your fuel tap isn't blocked. What I did to get around the problem was to convert the fuel tap from vacuum fed to gravity fed (HRC recommended mod for racing).
See: https://akhara.com/nc30/fueltapmod/index.html
Slight performance advantage to this as its said to give better fuel flow at high speed.

Also some redex won't do any harm either - could be some crap lingering in your tank.

Battery:
As far as I know, it might not be charging fully but it shouldn't be running down at tickover etc. I tested the voltage at 5000rpm and my battery was charging at 15V, which is said to be ok. It was still running down last time I went out for a ride though Your guess is as good as mine. I intend to fit a voltmeter display to my dash so I can monitor the voltage on the move. I've heard reg/recs can sometimes play up randomnly.

[mamak]

Thanks for the info, Maurice.
Has the fuel problem recurred?
Also I have a decent reading of 15.5V for the battery but When I take it on long high speed runs the battery doesn't seem to run down. Anyway this weekend I'm going to ride the bike really slow to see if it runs down from being fully charged.
I'll post my result on Monday.
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sliding by the seat of my pants. OUCH!!!

[EuropeanNC30R...]

With recent crappy weather and the fact I live two minutes walk from work I haven't had the inclination to try it out yet. If this weekend is ok I'm gonna take it for quick run.

[Claud 14.7 to 1]

Battery shouldn't run down at idle, even with the electrics on.

Think mine is in the region of 13v at tickover. Well whatever it is, it is more that 12.5v ish input which is what a full battery is.

Does the battery hold its charge when on the bike (bike turned off), or does the voltage go down if/when the battery is off the bike? Could be a leakage if it's going down when connected to the bike (with bike turned off).

Other that make sure your wiring for the charging circuit is all good, with low resistance readings. Doesn't hurt to give all the contacts and connectors a good clean.

Dunno, hate the electrics on those Hondas. Pretty much everything has went on mine - stator, reg/rec and the wires being corroded and generally crappy didn't help either.

[EuropeanNC30R...]

Yeah mine was 13V at tickover. I suspect either my 2 month old battery is duff , or the reg/rec randomnly plays up.

[Claud 14.7 to 1]

Yer that's the thing... And they never go at the same time either. My faults were one after the other and over some time.

Yeah good chance it's one of those two Maurice. Reg/rec are fussy little buggers, mine would work ok untill about 1-2 mins of the bike being on then it would go crazy and start burning up. Hmmmmm

[mamak]

Sorry for the late update. No more fuel problem. There were no blocks or anything. Redid the carbs. It's sorted now so go figure. The o-ring on the fuel tap was gone, replaced that but this doesn't have anything to do with fuel flow. Its just a seal to stop the fueltap from leaking.
I agree with you both, it seems the regulator/rectifier is very temperamental. I eventually found my problem. When revving the bike at 5000rpm the charge voltage checks out. After checking that all the wires had continuity I checked out the regulator/rectifier. There are specific readings to be obtained when checking across the terminals of the regulator/rectifier and the wire harness leading to the battery and from the alternator. The alternator readings checked out (thank God), however the regulator/rectifier didn't. So I guess thats my problem. I hope to get a new unit this weekend.
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sliding by the seat of my pants. OUCH!!!

[Stew]

Did the reg/rec solve your problem?
M has just recently had problems very similar to yours. We solved the fueling problem by carrying out the fuel tap mod but today M was left stranded when her bike just died on her as she slowed down to run right. There was not enough power to start the bike again I rode out to her (from work) and as I pulled up we tried to start it again and it started fine
A couple of bikers had pulled over to see if they could help but they couldn't figure out what had happened and it just seemed like the battery had died with no power, not even enough to turnover the starter motor.
Weird but lovely things these little 400s.
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"Unlike public school you don't need to have your arse up and your head down to go a long way...."