Yamaha TRX850 Enthusiasts Forum

Strange problem this.

Bike fails to start - no click or whirring when starter is pressed. Bugger, say I. All other electrics work 100%; battery is 1 year old. Seems like a clutch or sidestand switch problem, as the bike had started refusing to start in neutral unless the sidestand was raised. However, yesterday me and a mate checked most of the obvious suspects (clutch switch, sidestand switch, neutral switch circuits) with a multimeter, no problems. Checked all fuses and connectors, all sound.

We decide to try a bumpstart down a gentle slope. For some reason, I'm idly thumbing the starter button and then keep it held down. Just _before_ I actually let the clutch out (building up a little momentum), the engine starts. Idles fine, runs normally. Turn it off and on again immediately and it starts off the button. Repeat a few times, still starts. Turn it off and leave it 10 seconds or so - it doesn't start. Push it along for about 5-10 seconds, holding starter button down and it starts. We try this in neutral, in gear with the clutch in, same result. Seems to work at any speed, as it worked pushing the bike up hill.

So now I have to do pose-y TT style push starts every time I want to ride the TRX. Ho-hum. No good unless I weld a fake kickstart onto the frame and start dressing in black leathers and pudding-bowl lid. But then I end up buying a Harley and turning into Steve Rose.

Our theory is that the old and non-functional Datatool series 2 alarm in it (long since lost the toggles for it and can't be bothered taking the loom to pieces to remove it) has suddenly decided to activate its immobiliser. Because we seem to recall that these alarms are set up so they can't kill the ignition when the bike is moving (for obvious reasons), we think pushing the bike for a few seconds convinces it to allow the starter to work.

Does anyone (a) think our explanation is crap (well obviously, but give reasons!) and/or (b) have a better explanation?

(Full disclosure - we didn't test the little starter relay thingy (lives under the rear tank hinge, not the starter solenoid), because it seemed to require lots of work and I would just get confused trying to do the test sequence in the Haynes manual.)

pull the lockout relay. short out the 2 blue/white wires in the plug. if it starts then the relay is knackered.

jump the battery to the output (black) side of the starter solenoid. if it starts the solenoid is knackered.

if neither of the above work then your alarm may well be suspect.

In the event your starter motor is knackered I have a spare. I also have a spare sprag clutch if it turns out to be jammed.

^what he said ^,,,,, i think mr young has all the TRX spares in the world

youngy wrote:pull the lockout relay. short out the 2 blue/white wires in the plug. if it starts then the relay is knackered.

jump the battery to the output (black) side of the starter solenoid. if it starts the solenoid is knackered.

if neither of the above work then your alarm may well be suspect.

In the event your starter motor is knackered I have a spare. I also have a spare sprag clutch if it turns out to be jammed.

Thanks! That sounds simple enough for me to understand. I assume the lockout relay refers to the larger of the two directly under the rear tank hinge?

I have the same problem with mine if I leave it on the rear paddock stand for more than 2 days.

When i go to start my bike it just makes a buzzing noise and the starter does not turn the motor over.

I think that the fuel some how drains into the cylinders through the inlet valves and causes an hydraulic lock that the starter cannot overcome.

Why do i think this?

Because when i take the drain bolts out of the header pipes under the engine raw fuel runs out.I then replace the bolts and the bike starts normally.

This has happened to me twice,and it worries me so I don't leave my bike on the rear paddock stand.Do you leave your bike on a paddock stand.

I hope this helps you.

idl1975 wrote:

youngy wrote:pull the lockout relay. short out the 2 blue/white wires in the plug. if it starts then the relay is knackered.

jump the battery to the output (black) side of the starter solenoid. if it starts the solenoid is knackered.

if neither of the above work then your alarm may well be suspect.

In the event your starter motor is knackered I have a spare. I also have a spare sprag clutch if it turns out to be jammed.

Thanks! That sounds simple enough for me to understand. I assume the lockout relay refers to the larger of the two directly under the rear tank hinge?

Yes it does. The other is the flasher relay.

this sound like the float valve in the carbs is not shutting off this is a dangerous situation you should get it fixed soon also are you leaving your fuel tap on prime ? if not the taps faulty as well ,, the tap should only open when the engine starts to run ,, it uses the vacuum from the engine to open the demand valve in the tap ,,,,,,,,,hope this helps

kenmore wrote:I have the same problem with mine if I leave it on the rear paddock stand for more than 2 days.

When i go to start my bike it just makes a buzzing noise and the starter does not turn the motor over.

I think that the fuel some how drains into the cylinders through the inlet valves and causes an hydraulic lock that the starter cannot overcome.

Why do i think this?

Because when i take the drain bolts out of the header pipes under the engine raw fuel runs out.I then replace the bolts and the bike starts normally.

This has happened to me twice,and it worries me so I don't leave my bike on the rear paddock stand.Do you leave your bike on a paddock stand.

I hope this helps you.

have you checked your oil? cos the bottom end of your motor is going to be full of fuel if what you say is correct.

your fuel pump must be knackered as well if it's allowing fuel to fill the cylinders like that, unless you have fuel running back through one of the vacuum lines into the inlet, from a holed pump or tap diaphragm.

kenmore wrote:I have the same problem with mine if I leave it on the rear paddock stand for more than 2 days.

When i go to start my bike it just makes a buzzing noise and the starter does not turn the motor over.

I think that the fuel some how drains into the cylinders through the inlet valves and causes an hydraulic lock that the starter cannot overcome.

Why do i think this?

Because when i take the drain bolts out of the header pipes under the engine raw fuel runs out.I then replace the bolts and the bike starts normally.

This has happened to me twice,and it worries me so I don't leave my bike on the rear paddock stand.Do you leave your bike on a paddock stand.

I hope this helps you.

I had the bike on a rear stand for about 2-3 days just before this to change a tyre. When I got it off, the starter worked but it didn't want to start (float bowls empty?) immediately.

Not sure what the logical connection would be though, as mine doesn't make funny noises when it's refusing to start - it just does nothing, as if you had the sidestand down or tried to start in gear with clutch out. And it has done about 60 miles since the problem began, so any fuel buildup should be well and trulied by now.

Thanks for the replies.

What I can't understand is that the problem with starting only occurs when the bike has been left on the rear paddock stand for a couple of days, but I will check out the items mentioned.

Also another thing is that I keep a close eye on my oil and it doesn't appear to be making any.

That is that there is no sign of fuel getting into the bottom end of the engine.

Would hate to blow Trixie as she only has 24,000KLMs on her, and will be 7 years old this october. I have put 10,000 of those on her in 13 months and the motor sounds the same, and performance has not altered either.

Adios for now, will let you guys know what I find.