Kawasaki GT500 wont rev

Hello all,

I just got a used GT500 everything seemed spot on. The petrol was very
low and it started spluttering a bit so I moved over to reserve after
which it starts and idles perfectly but when I try to accelerate it
just dies. If it does rev up slightly the rev meter drops right down
to zero as soon as I try to accelerate.

Could this be dirty petrol/water or does the fact that the rev meter
drops to zero even though the revs seem to me to be higher indicate an
electrical fault?

Many thanks,
David

 

Well, except for the fact that there's no such bike. GT550 perhaps? Or
an old Suzuki 2-stroke triple?

Well I'd suggest as a starter you put some more petrol in it - if it
was low enough to be on reserve how do you know there's enough to run
properly. If you've done that and it's still doing it then it'll most
likely be the old "Shit in the carbs" problem.

Unlikely to be connected, unless you're saying that the whole
electrical system is turning off, in which case it may be a faulty
kill switch or a stand/clutch interface switch.

--
_______
..'_/_|_\_'. Ace (brucedotrogers a.t rochedotcom)
\`\ | /`/ DS#8 BOTAFOT#3 SbS#2 UKRMMA#13 DFV#8 SKA#2 IBB#10
`\\ | //'
`\|/`
`

 

Well, except for the fact that there's no such bike. GT550 perhaps? Or

Yes it's a GT550. Thanks all - as always very helpful.

 

Yes, absolutely. I'm assuming you mean GT550, btw.

I had this on a GT750 (same instruments): the moment it started playing
up, the rev counter needle plummeted.

In my case, it was the sidestand switch, so start there.

 

Ding. The latter.

 

Well, Albrecht, the symptoms are identical to what I experienced on its
sister model.

 

Yes I filled it earlier and it improved slightly after 5 miles at 5
miles an hour (I made it back to the office) - I just went down now
and checked it and it seems perfect.

David

 

Well, Albrecht, the symptoms are identical to what I experienced on its
sister model.[/QUOTE]

Extrapolating again!
--
_______
..'_/_|_\_'. Ace (brucedotrogers a.t rochedotcom)
\`\ | /`/ DS#8 BOTAFOT#3 SbS#2 UKRMMA#13 DFV#8 SKA#2 IBB#10
`\\ | //'
`\|/`
`

 

Thanks - I think I can short the switch easily enough.

 

Extrapolating again![/QUOTE]

Absolutely. But you tipped the sidestand switch as well.

On the GT750, it was misfiring and it was a nearly new bike, and I was
wondering what it was - fuel? Plugs? And then I saw the tacho needle
dropping, as dead as a flat hat, and the penny dropped with it.

 

Remove what would be the sprocket cover if the GT was chain drive.
You'll have to remove the gear lever first. Behind the cover, there are
two wires that go from the switch into the loom. They just plug in,
male/female.

Unplug them.

Plug the connectors in the loom together, male/female.

Job done.

(I see you've sorted it now, but on old Kawasakis it's an essential
thing to do anyway).

 

Absolutely.[/QUOTE]

Heh. Just a nibble, really.

I've never had personal experience of this on the kwaks[1] I've owned,
but it's a perrenial problem, so always worth a guess.

[1] GPZ550, GPX600
--
_______
..'_/_|_\_'. Ace (brucedotrogers a.t rochedotcom)
\`\ | /`/ DS#8 BOTAFOT#3 SbS#2 UKRMMA#13 DFV#8 SKA#2 IBB#10
`\\ | //'
`\|/`
`

 

The thing is, if it's a fuel-related misfire, the tach won't be
affected, because the ignition system is still sparking as it should. If
the tacho suddenly starts dropping, then the odds are that it's ignition
related, because the GT series tacho is electronic and works off the
ignition.

Wonky ignition = wonky tacho.

 

message

However, if the fuel is contaminated leaving the plug(s) wet and non-firing
then the ignition system is affected and the tacho reads low or not at all;
so they are not entirely unconnected systems.

 

Hm. True..... but the current is still being passed to the plugs, no?

 

You learn something every day. I always assumed that, at least on the
Italian SOBs I have with electronic tachos, that the 'blip' is picked up
direct from the transducer and so would be independent of the plug.

There are dire warning about not attempting a spark without a plug being
connected IYSWIM so presumably that is why.

--

+-------------------------------------------------------------+
| Pete Fisher at Home: |
| Voxan Roadster Gilera Nordwest Yamaha WR250Z |
| Gilera GFR * 2 Moto Morini 2C/375 |
+-------------------------------------------------------------+

 

Wot he said.

Although having said that my brain insists there is a recollection in
there somewhere of one of those exception and rule events that has been
consigned to not as easy as it was to get at storage but nonetheless
there to annoy me anyway.

 

I had a similar problem with my GT550, tacho bouncing around and an
occasional misfire. This was followed a few days later by it suddenly
firing on two cylinders only, thankfully close to home. Needed a new
coil to put things right again.

 

It was very rough - sometimes able to move when the lights went green
and sometimes having to wait. At the very end I was suddenly able to
rev it up to a few 1000s but still very rough and not consistent.
After leaving it for a couiple of hours everthing was fine - rode
home the short journey. In the interest of science I just went out now
and started it up and it seems fine.

I think the side stand switch doesn't cut out the engine when revving
in neutral. In my case then enging didn't cut out just revs dropped to
0 until I let go of the throttle.

Thanks.

 

While it may vary by make/model, the electronic tacho on my old Morini
Strada would under-read (/2-4) if the plug was fouled on the cylinder it was
connected too. Maybe if the plug is tracking-out (effectively shorting at
lower than spark voltage) there's no "blip".

We also had a few bikes down the workshop with similar symptoms, including
IIRK a Ducati 860.

Hmmm, perhaps it's an Italian thing...