Hard to crank when hot

[hmmmnz]

bike is a 2001 vtr1000
new battery, decent new reg/rec
stator produces decent ac voltage when running,
reg/rec is producing a decent and constant 14.4 ish vdc

when the bike is cold it cranks over fine and fires into life no problem

but if i ride say 10 mins or more and get the bike hot,
stop, and then try and start it, its like the battery doesnt have enough power to turn over the bike.

wait until its cold, say an hour, then it'll turn over and start fine.

its like some thing is tightening up when it gets hot,
but ive had it happen and had the mrs come with jump leads, and its started, so may be its some parasitic load when the bike is on.


I've cleaned all the feed wires that come off the starter relay.
added an extra earth from the battery to the subframe


In the garage I ran it up to 105'C to make sure the fan kicked in.
Stayed at a constant 14.4 with the lights off, and 14.3 with them on, 14.3 with the fan on as well.

A constant 0.6amps to the battery
And more when the lights were on.

Turned the bike off,
Voltage was 13.2v

Waited about 5 mins to simulate getting gas,
Temp was sitting at 87'C
Tried to turn over, drawing peaks of around 320amps
Averaging about 200amps, but not Turing fast enough to start.

Voltage was 13.01volts
Temp. 76'

I waited 30mins

temp had droped to 53'C
and voltages was 13.07V

turned over and started easily.

-

wtf is going on,

some thing must be expanding when its hot and increasing the resistance on the drive train making it hard to turn over. Or may be the main starter cables are poked/ too small to do the job when hot

any guesses?

Cheers
Hmmmnz

[Wicky]

A clicking starter relay is a sign that there's some eclectrickery getting through but not enough to turn the starter motor.

What's the terminal connection like under the rubberhood on the starter motor? Any sign of corrosion on the nut & bolt.

If you short the starter relay does the starter motor turnover okay?

Same battery?

Fri Sep 16, 2016 7:14 am

It's a brand new lithium battery that I've fitted a couple of days ago.

[Watty]

Have you recently fitted MCCT''s?

[hallie]

Had similar problems and I stripped the petcock diaphragm to check for pinholes/tears. None present but it was gunked up so I cleaned it up and that seems to have sorted my problem. Worth checking out

[hmmmnz]

No manual cct's ( they are sitting here, waiting though)

Starter relay doesn't click. It pulls in fine, but the starter motor struggles.
A new one is on the way though.


The starter motor nut looks a bit sh1t, I have a mate sending a good used secondhand unit up.

Battery is a nice 14ah exide unit, I don't trust those lithium ion batteries, never had much luck on another bike.

I've ordered some new cable.

For future reference the stock cable is AV15 cable (crazy Japanese numbering for #6 awg)

Which is about 13.36mm2 so I'll replace that with 16mm2 oxygen free flex cable. And some decent lugs.


Cheers for the ideas guys, much appreciated

[sirch345]

I had a similar problem with my Storm not so long ago, it didn't like starting when hot. It turned out the starter motor needed servicing. So definitely worth trying another known good one,

Chris.

[hmmmnz]

Right update,
I replaced all the starter cables with 16mm2 cable.
With decent hydraulicly crimped lugs,

DSC_0986.JPG (2.69 MiB) Viewed 2180 times

I cut the original cable open, and the copper had turned black.

DSC_0985.JPG (2.39 MiB) Viewed 2180 times

I replaced the starter motor and gave it a quick Polish on the wire wheel

DSC_0989.JPG (1.97 MiB) Viewed 2180 times

And since everything was out of the way, replaced the cam chain tensioners. As well.

Also had a leaking fork seal, so killed that bird whilst I was at it.
I hate not having a center stand!!
Made do though

DSC_0979.JPG (2.78 MiB) Viewed 2180 times

Heres a start up video as well.




So all is good in the world

Cheers for all the help guys.
Much appreciated,

[AMCQ46]

nice work, bike is looking good


Post up some photos of the little Suzuki as well, it looks cool

[sirch345]

Happy days, good work with replacing those cables. As Al says, your bike is looking good, and starting very nicely

Is that little Suzuki a B120

Chris.

[hmmmnz]

Yeah a little 76 b120,
I bought it for the mrs a couple of years back,
I had one in nz which she loved, so I got her the little pink one for her to commute to school on (she's a teacher)

Here's a little start up video


And the bridgestone rs200 2 stroke twin I've just "finished"

[sirch345]

Yeah a little 76 b120,
I bought it for the mrs a couple of years back,
I had one in nz which she loved, so I got her the little pink one for her to commute to school on (she's a teacher)

Here's a little start up video


And the bridgestone rs200 2 stroke twin I've just "finished"

Wow that makes the B120 41yrs old this year.
I used to work with a guy who had one of those many years ago, he used to ride it in all weathers come rain or shine as he had no other transport. That little Suzuki just kept going and going for many years, mind you he did have it serviced regularly and he never rode it hard.

Good to see one again and thanks for posting up the video's. Listening to the B120 took me back

Chris.