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Cota 348 Magneto


bpilgrim
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Hello,

I have been struggling to get a spark out of my 348, it's had a new plug, HT lead, ignition coil, points, condenser, woodruff key and wiring from the magneto coil. To try and reduce the number of potential problems, I have left out the kill switch, and have been trying for a spark directly from the end of the HT lead to a bare part of the block. I had the gap set to 15 thou, and left the timing as I'm just trying for a spark first (the engine is still out of the bike).

The magneto coil does appear to be rather worn, the plastic shields at the top and bottom of the individual coils are quite bent and the soldered connections may be touching the inside of the flywheel.

So I'm thinking the only thing left is to buy a new magneto? I was wondering whether the Cota 348 shares a common type magneto with either the Cota 247 or Montesa Scorpion. I have found one of each for sale, and the Scorpion magneto appears the same but is in Oregon...

Thanks in advance for your advice,

Ben

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Make sure you have the wiring correct and the points mounted properly so that the contacts are correctly isolated from the engine. Then

I'd start by checking the grounding - make sure if the frame or point on the engine where you earth has the paint or powder coating scraped off. Then double check your condenser and ensure it is earthed properly - they work best mounted under the tank rather than behind the magneto- you need to measure the resistance (ohms) of the coils - remove the spark plug out and turn engine over where points are shut they should read 0 or close to it when they are open should read .5- 2.5 ohms (approx)

You can get the problem coils rewound for a lot less than a replacement and then you know it's right. But make sure you double check condenser..

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Hello again,

Thanks for your advice, at last I have a spark!

It was the wire that comes from the condenser to the points, the crimp connector was quite long and was almost touching a screw, all I did was file the ends, put it back together and I got a brilliant spark.

The engine is back in now, timing set at 1.8mm BTDC, fingers crossed for some combustion tomorrow!

What sort of fuel/oil mix would be suitable? The oil is race spec valvoline 2T oil, as I have about 15 litres of it! The engine hasn't ran for a couple of years, 50:1 ish?

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