Electrical issue on 4th gen

I posted elsewhere that I thought it was time for some maintenance on my 4th gen 750. Got her all back together this morning and now after riding for a while, when I turn her off, she doesn't want to start again.( well at least until she cools down)

It happened on the way to work this morning, started raining so stopped and turned ignition off. Got gear on then went to restart and it seemed the battery didn't have the power to turn the engine over and she wouldn't start. Fortunately I was outside an auto shop and a guy had a jump start pack which once connected fired her up as normal.

Rode to work after promising to drop 6 pack of beer back at some stage:smile: for helping me out of a tight spot and once I stopped at work I tried to restart the bike again, with the same problem wrrr wrrr then nothing. Ordered a battery which was sent via courier to me today. Now the interesting thing is I checked the bike several times during the day and it started first time and as per normal, no problem evident

Started first go when ready for home tonight and checked once home by turning off and trying to restart again, same bloody problem again wrrr wrrr then nothing.

Seems that as the bike get's hot something is shorting or the battery has reached the end of it's life.

I have just replaced air and oil filters, both left and right side engine cover gaskets, spark plugs and head cover gaskets.

Could I have stuffed something up when I had her apart(very vague I know) or should I fit the new battery(as I write this I think that is probably my first step)

Any suggestions would be greatly appreciated.

Oh and I am pretty sure the RR has been replaced as the one on the bike has large fins on it? could it be another electrical issue as there have been no warning signs in the 5 months I have been riding her?
Thanks
Shane

 

Been home two hours so thought I would check the bike again, bloody thing started first go again.

Seems to me, it couldn't be the battery? arrrggghhhh not a dreaded electrical issue, I am not fond of those.

Any ideas?

Will have a look at wiring tomorrow after I finish mountain biking on my new bike I finished building recently. Maiden voyage tomorrow:biggrin: hope it's not too wet.

Will check all fittings where I was working last week on the bike and see if anything looks sinister.

Cheers

 

If you've got the battery I'd go with that but check hot and cold that the RR is doing it stuff

Good Luck

 

Usually if a battery 'comes back' after a couple hours on its own without charging it's probably good. Rules of thumb...battery discharges prematurely while sitting - weak battery...battery goes dead while riding - charging system issue.

Your next step is to inspect charging system. charge your battery, or put the new one in it (good fully charged battery should be around 12.6VDC). Go for a short 10 minute ride. Access your battery terminals (make sure they're tight while you're at it) and put a DC voltmeter across them. Rev the bike to around 4000 RPM and read your voltage. Report back with your findings.

If your charging output is good, you should read around 13.5 - 14.5 VDC with this test. Much less than that and you need to further inspect wiring, stator and RR to narrow the problem down. Electrical? Don't worry, charging systems are as easy as it gets and we'll guide you through it. If you don't have one, you can buy a cheap voltmeter at any auto parts or electrical store...no need to go fancy for this. BTW, nice pedal bike.

 

From your description, I suspect the problem is in your starter circuit, as opposed to the ignition or charging circuits. I would check your starter relay for loose connections etc. I'm not an expert so this could be totally wrong, but HTH, good luck and let us know how it goes.

 

Thanks for the info guys and will check in later.
Time to go buy a voltmeter after my mtb ribe and do some testing.
Will let you know what comes of it.

 

Well Dizzy I had a look and connectors and wires seem okay.
Went for a 15-20min ride and just checked the readings.
Before ride battery reading 12.43 dcv with ignition off
After ride at idle of approx 1200-1300rpm battery reading of 12.66dcv
And at 5000rpm reading of 14.3 dcv.

Turned off and restarted, did again and each time it gets harder to turn over. Could it be the starter or is the battery reading too low at idle?
All of this has been done with the old battery connected.
Should I connect the new battery and do the same tests?
Thanks
Shane

 

Good job. looks like charging system is checking out OK. A lower voltage at idle is normal. A good fully charged battery should be around 12.6VDC, so you started out with a partially discharged or weak battery.

Alright, let's try a little stress test for your battery. Go for your ride again, do the same thing (get it too fail). This time, bike not running, key off...read your battery voltage. Leave the probes on the battery terminals (if you don't have little clips for the probes you might have to get beverages and have a helper over), turn the key on and see what your battery reads for VDC. Then, turn the starter motor over while watching what the voltmeter does. Being a very large load for your battery, you're gonna notice a voltage drop. A good strong battery will keep the voltage well over 10 or 11 VDC. If you see much less than that, good chance your battery is getting weak and you should replace it, or charge it...get it tested.

A couple less likely possibilites are starter relay (as slothrop suggested), the starter, or the wiring. You can easily test the starter relay. Find it by following the large positive cable from the battery, it will go directly to it. You will also notice a large cable going directly to the positive lead on the starter motor from the relay. The most definitve test for the relay to test voltage drop across the two large cables. Pull back the rubber boots that cover them (careful not to ground the terminals or your probes when you're doing this) and check the VDC across the two large terminals. You should read around 12.6 VDC (same as battery). Engage the starter button and watch what happens to the voltmeter. If you're starter relay is good, the voltage should drop to nearly zero while the starter is turning. If you're reading much more than 2 VDC approx, it starts to look like the relay might be in question.

That should give you enough testing to do for awhile...let us know what you're finding.

 

This thing is giving me grief,haha.
Have just done the VDC check as you mentioned after riding and getting the starter to fail.
Key off battery reading 12.15DVC
Turn ignition on and reading changes to 11.7DVC
Then turned starter and reading dropped to read between 5.6-6.5DVC

Thought you beauty it's the battery, so seeing as I had the new one sitting here I prepped it and put it in.
This gave me the following readings
Key off with new battery 12.72DVC
Key on as above 12.25DVC
Then whilst hitting the starter 7.8-8.4DVC
Seems it ain't the battery as she will not turn over again at all now even with the new battery.
I am thinking now it may be the starter relay as when trying to start there is a loud clacking? noise from where the starter relay is.

I have located the large cable that runs from the + terminal on the battery to the starter relay, though I am struggling to find the end of the cable coming from the starter motor and or going to the starter relay.
When you say to check the VDC across the two large terminals, do you mean at the starter relay or at the relay and the starter motor?
Thanks again dizzy.
I'll get to the bottom of this eventually.
Good thing is I have learned about testing voltage etc.
Cheers

 

Well Slothrop you may well be right as after doing some testing it appears the R?R etc and battery are fine.
Am going to do the test on my starter relay that dizzy outlined below and see what reading I get.

Relay connections and fuse are all good and interestingly enough I found a burnt out old fuse where the replacement/spare fuse(30amp) sits in the relay housng.
Maybe the previous owner had the same issue. The fuse being used is fine although I replaced it anyway to be sure.

If the starter is the issue should I get a new genuine item and what could be causing the problem, wiring to from the relay is my guess and may be I should replace that at the same time?

Will see what happens in the morning.
Cheers

 

A good fully charged battery should only drop one or two volts when you engage the starting system. Yours is dropping nearly 4.5VDC. When you find out what's consuming the excessive voltage, you'll have found your problem. Think of it this way. Any load, cable, connection point consumes voltage. A good connection or wire will consume very small voltage...usually less than than .1 VDC. A load, like your starter will consume more VDC. By probing various sections of wire and connections you can find this out.

For example the starter relay essentially makes the connection between your battery and starter across the big cables when you hit the starter button. Ideally, you'll have nearly all the battery voltage going to the starter. If there's a poor connection inside the starter relay...it will consume more VDC than it should, and the VDC going to the starter will be reduced. So to test the relay directly, read the voltage across the big cable terminals (on the relay) when you hit the starter button. Ideally the voltmeter should read very small amount...like .1 VDC...if you read 3.0 VDC...it indicates a poor connection inside the relay. If you did the same test...but placed one probe on the positve battery terminal, and one on the starter terminal...it would be essentially the same test, but you'd also be reading the voltage drop on the connections and cables in addition to the relay. So let's say you probe the positive lead post on the battery and the adjoining post on the starter relay and found it was consuming 3.0 VDC when you hit the starter button...in that case you could infer a bad or corroded connection somewhere between those two points.

If I were to guess, I'd say it's starting to look like the starter may be the culprit. But with a little 'probing' you don't have to guess.

 

Phew this is getting interesting and will do test on starter relay today.
Figured you were referring to the two cables that mount onto the relay, under the rubber cover.
Will test across these and check battery cable(+) as well while I am there.
When I checked the relay connections yesterday they seemed fine and were nice and tight.
As mentioned above the spare fuse(30amp) was an old blown fuse, so maybe PO has had issue before.

Be back in a couple of hours with more results of testing

 

Did the test on the starter and all is good
reading with ignition off 12VDC
ignition on 12.45-12.5VDC
and when I hit the starter it drops to almost 0VDC (0.2)
tested the positive lead and that drops to almost 0VDC as well.

Seeing as the restart is harder when the bike is warmed up/hot could it be a faulty R/R?

This is driving me crazy.
All my connections look really good as do the cables.
The R/R has a number SH701-12 T3.7 191

 

The saga continues.:crazy:
Thought I would do some testing on a cold bike at first start this morning and got the following readings

Ignition off 12.52VDC

Ignition on 12.03VDC

Starter held to start dropped to 10.99VDC

Engine idle approx 1200rpm 13.4VDC

Engine 2500rpm 14.5VDC

Engine 4000rpm 14.3VDC

Engine 5000rpm 14.1VDC

If what I have read and understood all these readings are pretty well spot on

What other accessories could drain the battery when running so that it wont restart when hot?

 

...An overheated R/R will stop functioning properly at a certain temperature, and show normal function when cold. Ask me how I know.

 

Bet there is no reason for me to ask as being an owner of the vfr you will have run into this before:biggrin:

I am starting to think that is the issue and what is the best R/R to replace with.
What did you install, was it the VFRness and R/R from wiremybike.com?

Thanks VTViffer

 

I don't understand why you would think this based on your testing...you've already checked the charging when hot and the symptoms were present. If you have doubts, by all means get it hot and double check it. Charging system tests at the battery are reliable indicators...if you have over 14 VDC at the battery at a modest RPM your charging system is fine, including the R/R...trust your meter.

Note when your bike was working (cold) the VDC at the battery only dropped to 10.99 when the starter was engaged, which is normal. When you did the same test hot and failed, the voltage dropped to under 8VDC. Yet the initial VDC was about the same...around 12.5 VDC.

Sounds to me most like you have bad starter. Most likely the armature windings are leaking to the core of the starter (it's shorting out) when hot. I've seen this very thing many times on Honda starters. The best fix IMO is to replace the starter.

 

I agree with VT Viffer, it is your R/R. We probably share the same learning experience. I don't know about him, but I was 100 miles from nowhere when I learned.

 

I hear what you are saying and is there any way to know or test if the armature windings are leaking?
When you say to replace the starter, are you referring to the starter motor.
Is this an easy job to do?
Cheers

 

I don't know how to test a starter for this problem, but it's pretty easy to yank it out, provided your fairings are already off.