1999 vfr800 refusing to crank over and start

Hi to all the VFR people.

I hope you can help and bear with me as I'm a mechanical dunce.

So I followed the brilliant advice given and changed the reg/rec for an electrix one (I'm in the UK) plus carried out the drill, and fitted a new battery to be on the safe side. All was fine... until recently.

I'd been out for a few early season rides with no issues then one day I rode into work and have to pull up to open a gate. Tried to start the bike again and it reset the clocks and wouldn't crank over. It sort of tried but barely and not enough to start. The fuel pump primed and no kill switch issues, or not being in neutral or anything like that. The temp was around 98 - 102 c at that point. I parked it up and left it for the day, until going home when it started again, not strongly but it did start.

I had no other issues and had the bike serviced, and rode it a couple of times without issue. I recently went out for a decent length ride and upon returning home the same thing happened with it not cranking over properly. I took the rear fairing off and the yellow cable connector from the stator to the reg/rec had burnt (hopefully photos included). Bugger.

I've stripped the connector, connected it back together with solder and heatshrink sleeve so I could perform the drill but I can't get it to crank over to do most of the tests. Battery is charged, tested, and fine, as is spare battery. Fuses seem ok. I didn't find any other crispy wires or any other burnt bits.

I carried out the stator test for resistance, which 0.5ohms on all cables and continuity was fine. However I can't start her up to carry out and more tests. I've since stripped the solder and temporarily connected them in case it was my soldering and still nada. The lights all come on fine, horn strong, it seems to prime fine but drops quickly when I try to crank it then just clicks. It's really difficult to bump it where it's stored but tried a few times anyway with no joy.

With zero knowledge off the top of my head I'm guessing the stator is gone but I'm just completely guessing. I bloody love this bike but I'm getting really frustrated. Any help is appreciated and sorry if I come across as stupid or missing anything ridiculously obvious.

Thanks in advance everyone.

 

Trying to upload a video of not starting but can't seem to get it to work.

 

Battery tested how? Testing with just a voltmeter is not testing. A battery needs to be load tested. Your initial description sounds like it could be a failed battery. I've dealt with two suddenly failed batteries on two separate VFRs within the last 3 years. Clocks reset and bike barely tried to turn over.

If battery is definitely good, I would then start looking at starter and starter relay items. Main fuses and their holders. Ground connections.

The stator shouldn't have any say on the bike's ability to fire. If everything else is fine, the stator can be completely unplugged from the regulator and the bike will start and run for a while solely off a good battery.

Don't do anything drastic until Grum chimes in.

 

Thanks for the reply, I really appreciate it. As you can tell, I have pretty much zero knowledge hence the wild guesses.
Do I need to take it to a garage to be load tested?
I'm happy to buy another battery, and can pick one up in the morning (we have coronation bank holiday so shops closed). The one I bought to replace the other was a YUASA YTX12-BS, do that sound right?

Thanks again for the help

Edit: I've been to the bike to try and start it while holding the voltmeter on. The voltage drops from 12.9v to below 6. I don't know if that's significant I just thought it might add more information. I've no idea if that's normal or not.

 

Any reputable auto parts store has a battery load tester to check customer battery condition here in the states. Is that not the same case in the UK?

 

I have to confess it's not something I've looked into before. I think there's a couple of places I can try near to work tomorrow. We are not quite as equipped as the states for big auto parts stores. It's mainly Halfords and Kwik fit type places. Both may do the service though.

Thanks again for the help.

 

Any reasonable small garage will have a battery tester in their tool kit, as should any motorcycle dealer worth doing business with.

 

If you have access to a car and jumper cables, I would try a jump and see if that allows the bike to start. Batteries can fail through internal shorts and they can still show a decent voltage on a meter but seriously lack the necessary current to spin the starter and fire the ignition and injection. If the battery is badly enough shorted it can cause enough current leakage to defeat the jump battery too in which case you should pull the bike battery out of the circuit.

 

This isn't a proper diagnostic of any sort so take the battery in to a shop, but I usually find the following signs when a battery is toast. The voltmeter will read the 12.5V, vehicle barely tries or won't crank, putting the battery on a smart charger will return a fully charged status very quickly. Like within 10 - 30 minutes. If the battery were truly depleted but still of good capacitance this charge time would take MUCH longer.

 

Great advice already.
- You've measured between phases of the Stator as being OK, the most common failure mode of the Stator is a short to Ground. Make sure you measure infinity between the three yellow Stator wires and Ground. The burn up of the Stator connector is a common issue.
- Measuring only 6 odd volts at the battery while cranking doesn't sound good at all, doubt that injectors could fire at that voltage. So battery capacity seems down. Are your battery terminals clean and tight? Absolutely need to confirm the health of your battery.
- Check the state of Both Main Fuses 30amp. Especially the fuse holder, wiring and inline splice for Main Fuse B.
- Remove and closely inspect the Red plug from the Starter Relay. The main Red wire connecting to Main Fuse A housed in the Starter Relay can suffer badly from overheating and high resistance connection this can melt the red connector plastic shell.
- You might have starter motor or starter clutch issue, if a known good battery doesn't crank the engine.
- As soon as you get the bike running, verify your charging voltage generally 13.5 to 14.5 volts. Check this at Idle and 5000rpm both hot and cold engine.
Good Luck.

 

Thank you Grum, that's great. Also thank you vfrgiving for the great advice, much appreciated. And to Terry and 50th.

So I took the battery to a battery specialist who load tested, and you're all correct - it was farked. Went back to the place I bought it from, who replaced it under guarantee. Before I put the battery on I checked both main fuses, the fuse holder and the red plug plus the wire connecting - all clean and no signs of burning at all. Popped the battery in, and she cranked over and started straight away. Phew, happy joy!

You are all fantastic

The only burnt part was the Stator connector. I have a spare connector and reg/rectifier but is it better for me to solder and heatshrink instead rather than use another connector? If of course via the drill and charging voltage that everything is ok. Can the connector burn up without any other issue?

A final thanks, this forum really is a brilliant place!!!

 

On the 3 yellow high voltage lines from the stator to the regulator it is most definitely better to solder and heat shrink. Neither of my VFRs have that connector anymore. The plug on the 12VDC side of the regulator I've left alone.

 

If you can source some use glue filled heatshrink.

This provides a waterproof seal and prevents any future issues.

And congratulations on getting bit running. Fault finding is all about being systematic and only changing one thing at a time.