RS 125 WONT START :x

[jez125]

hi

tried the suggestions people said

compression 137psi
kill switch off
carb jets and carb clean
new spark plug

Poured fuel down barrel but still will not start
spark plug is clean with fuel on it

spark is very good

ive cleaned it and tried firing it up just wont have it

i was suppose to be selling it but i carnt now as it isn't running uhhh any more suggestions please

[jez125]

Dont know if this helps but it has a plastic smell when trying to start it

[UrbanRacer]

[jez125]

kk i will try and trace the wiring back but even with a good spark and fuel down the barrel would this stop the bike from running?

[UrbanRacer]

Is the starter turning the engine?

[jez125]

yeah the engine is turning over but just not firing

starter motor fine and starter gear working

[MickC]

First you need to pin down where the smell is coming from. Look for bubbling of blistering on the electrical components and wiring. If something in the ignition circuit was/is shorting it could cause the ignition to fire at the wrong time, or it could be the timing is out or a combination of both.
But find the source of that smell first.
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[jez125]

hi smell is coming from the carb as ive take the air box off to take a look and when i twist the throttle to fully open the electric dips

[jez125]

so at the moment ive got the battery on charge as it is properly running low to trying to start the bike

[jez125]

right found out a bit more the earth wire coming of the battery is getting really hot and started to bubble so you are right so far as its an electrical what is the best option now

[bikenut]

:karma: jez125 3 posts up you say that lights dip when throttle opened wide..................is throttle cable sawing its way through a wire?????????? or something like that possibly.......long shot but its your bike.........FIND ELECTRICAL PROBLEM!!!!!!!!!!!!!!

[Robby]

If the negative (black) lead is getting hot, then it is trying to carry more current than it is rated for. Assuming this is a thick wire, that's an awful lot of current.

Start off by checking for corrosion on the battery terminals, and where the negative battery lead mounts onto the frame or starter solenoid.

If you had a short somewhere you would be blowing fuses. This suggests a short, an internally broken cable, very serious corrosion, or a loose connector somewhere between the negative lead and the fusebox, or on a part that isn't protected by a fuse (possible starter solenoid connection).

A bodge I have used in the past where I suspect that the wiring is corroded somewhere, is simply to run an additional earth wire from the frame back to battery negative terminal.

[Teflon-Mike]

To isolate a possibility of the starter motor shorting, try bump starting it; unless the black battery wire gets hot as soon as you connect it.

My best guess, is that the starter motor circuit is earthing out' could be that the brushes or even the windings in the starter have 'gone', or you have a loose starter lead, or something (Throttle cable?) earthinng the starter terminal either at the starter end or the solenoiod.

Other notion I have is something to do with the power valve servo; if the power-valve has siezed/jammed, and that is sucking loads of amps, trying to do it's 'pre-start-swing' between travel stops.

However; if the bike can be 'Bumped', so you dont have the starter motor dropping the battery terminal voltage or letting another electrical gremlin loose; gives you an idea where to start hunting.
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[Kickstart]

Hi

The starter motor doesn't have a separate earth wire. That is the main feed to the starter motor. I would suspect either the starter motor has shorted out internally, the feed wire has chaffed through and is shorting on something or that where the wire connects to the starter the nut it attaches to is shorting to the body of the starter motor.

The power valve doesn't have a servo, rather a solonoid that only draws a decent amount of power for a max of a couple of seconds before the control unit limits the power (ie, it is pulling against a spring, decent power to pull against the spring to open the valve and then less required to keep it open). They stick fairly often and won't cause a major problem (beyond trying to unstick them).

All the best

Keith
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