MTX125 weird behaviour

FFMan · Derestricted Danger Joined: 29 Apr 2015 Karma :

So I recommissioned an MTX that had been stood for a long while. Got it running well and managed 13 miles of hooning on it then it started cutting out so we limped home.

Once home I cleaned the carb again and it started and ran ok for a few mins, then I decided to leave it on tick over for a few mins - there was a strange click/clonk and it died and wouldn't restart.

15 mins later it restarted and ran for a about 1 minute before dying again.

I've disconnected the engine kills switch and checked all the connectors are sound and clean and check the earth on the coil mount. Battery is new and charges when the engine is running.

It feels as if once the fault had developed, its heat or time related as when left for a bit it'll restart for a bit.

I had something similar on a saab once with a faulty crank sensor - is this possible or likely ?

any help much appreciated - got me stumped until I get time to whip the stator side off.

doggone · World Chat Champion Joined: 20 May 2004 Karma :

Try changing plug(s)?
An old one would do to test so long as not longer or something stupid.

Nobby the Bastard · Harley Gaydar Joined: 16 Aug 2013 Karma :

Fucked coil. When a problem is that temperature sensitive it' s invariably a coil.
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trevor saxe-coburg-gotha:"Remember this simple rule - scooters are for men who like to feel the breeze on their huge, flapping cunt lips."
Triumph Sprint ST 1050

FFMan · Derestricted Danger Joined: 29 Apr 2015 Karma :

its a new plug - NGK - still possible

i'll try and source a coil

bikenut · World Chat Champion Joined: 21 Nov 2011 Karma :

does it have ht when it conks out?? you have already disconnected then cdi "kill"....but there are also coils under the flywheel.......ht coil first thought......
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nuts about bikes

FFMan · Derestricted Danger Joined: 29 Apr 2015 Karma :

I did hook up an electronic rev counter to try and establish if when it died, the spark had died. it was a bit inconclusive but it did show that on occasions when I kick it over it makes a 200rpm, and other times nothing. as it was a rev counter for 4 cylinder I think it was a bit hot and miss, but I suspect the problem is electrical.

I have ordered a coil and spare cdi unit. if that fails to improve matters i'll take a look at the pickup coil.

coil should arrive tomorrow - will let you know.

FFMan · Derestricted Danger Joined: 29 Apr 2015 Karma :

New coil seems to have fixed it Smile

thanks