RS125 Technical Help Please...

[Method]

Wannabe races stay out please, im not interested in your bull basically

With that out of the way, the problem:

My mates been having a bit of trouble with his RS recently, its a 2002 model 125 and its got ~6k miles on it.

Basically what seems to happen is that the bike will start up and run when cold, we'll ride down the road a little way then it will just cut out and not start again. When left for a little while it seems to start again but only for a little while, then the same will happen.

A few days ago i checked it and there wasnt a spark, a cup of tea and a chat later and the bike started up and ran again for a little while, then it died. I assumed the spark had died again but couldnt check because he wasnt with me.

Anyway, he went down to the local dealer where they told him the lower grade oil he had put in it would be causing this, i didnt believe it was the whole problem because the spark plug didnt look bad at all, where as if the oil was causing the engine to die - the plug would be fould...

Anyway he broke down last night and told me that he saw a spark from it and it was white, but it still wasnt starting.

His dad took a look at it and said that he cant see a spark now either, and thats with a brand new plug fitted.

Im heading over there in a little while to have a look at it again with him, but im not very clued up when it comes to 2 strokes. 4t's im fine with, but 2t's im not that great with So i was wondering if anyone had any suggestions on what i could check out whilst im round there?

My feeling is that its the coil - perhaps its on its way out, not quite dead yet, but getting there. Starts up and runs when its cold, but after a while the coil gets over hot and breaks down, thus no spark until it cools down again? Only thing is the coil doesnt actually feel warm to the touch like i would imagine it to... (btw if anyone has a link to coil testing tollerances for rs125's it would be handy, although im off to look for them now)...

Anyone?
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CBT Aug '03 ... Gilera GSM 50 ... Honda NSR 125 Aug '04 ...
Full Test Dec 04... Suzuki GS500 Jan 05... Suzuki SV650 Mar 07... Gixxer 6 K5 May 08... Oh and my 'Rado
My Bikepics.com - No Brakes, No Gears... No Fear.

[Rejimbo]

Can you bump the bike once its died??

[Kickstart]

Hi

One problem I have seen on a late RS125 is the ignition pick up develops too large a clearance to the flywheel. Causes an intermitant spark (one I saw could be bump started but not on the electric start as it would not spin up quickly enough).

The gap should be 0.5mm +/- 0.5mm (remember this will be to the bit on the flywheel that pokes out as a pickup point). At 1.5mm it was still running much of the time.

All the best

Keith
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Traxpics, track day and racing photographs - Bimota Forum - Bike performance / thrust graphs for choosing gearing

[GearboxGeezer]

Sounds like ignition, Happend to my ped ( 50cc geared )