Bike cutting out in the rain

[damhugs]

I have a customised bike with a lifan 250 engine. Had quite a few problems, most recently a vacuum leak from the carburetor causing to splutter and stall when the revs got too high. Thats now been sorted and has been fine since. Over the last week though every time it rains it has started doing exactly the same, spluttering and stalling as soon as it goes through a puddle or gets hit by same rain. Only when it rains though, it is absolutely fine otherwise.

Any idea what this could be? I live on a small island in Thailand and most mechanics don't have the intuitive to investigate the problem so I need a point by point of what they should look at/change/fix. It is also rainy season so as a daily ride getting to work is quite a challenge when the bike isn't behaving its in the rain.

Cheers!

[Mississippi Bullfrog]

Almost certainly going to be water getting into the electrics. First thing to check is the HT lead and spark plugs. Look for any signs of a crack in plug insulation - even a hairline crack will let water in which then arcs the ignition charge to earth. Here in the UK we ride in the wet most of the time so all electrics are sprayed with WD40 to keep water out.

[winston smith]

I've had similar symptoms in the rain.

my HT leads had come loose where they join the plug cap. A couple of clockwise turns of the caps tightened them up just fine.

[fastbob]

Yep , HT leads . If they can be detached from the coil I would simply replace them . One way to test them is to wait for it to rain and have a fiddle around with your bare hands with the engine running . If your arm goes into spasm you're probably on the right track .

[skyrider]

Bob means if you get an electrical belt and you have to let go of the lead fast you are getting there (but we all reckon you wont say anything when this happens)

[geofferz]

Which island? Just out of interest.

[damhugs]

Brilliant, thanks for the responses! Will check this out the HT leads and spark plugs today. I'm on Koh Samui.