Open the throttle and the engine dies??

[Matt Read]

Hi,

Here is an interesting one for you all!!

My bike (Suzuki GS125 1983) was running fine and I took it on a number of 100+ mile runs with no problem. Then when I went to go out the other day I started up (from cold) and as I went to pull away the engine stalled. I restarted and the same happend again and then again!!!

I then realised that as soon as I put the throttle on the revs would drop and unless I released the throttle the engine would stutta then die.

I thought it might have been that I had accidentally knocked either the throttle stop screw or the mixture scew, but despite many attempts at adjusting each of these one way then the next I was not able to stop the engine dying once I opened the revs (or the choke).

I then checked and cleaned the air filter and that made no difference, checked the carb and all was ok and the throttle cable, again no obvious problem there. The spark plug looked fine a bit of carbon deposits (suggesting the previous mixture was a little rich), but nothing to suggest a major probelm.

So any suggestions on what the problem might be or what I should check next, to speed up the fix.

Cheers Matt.

[Paddy Blake]

Did you check the diaphragm at the top of the carb for holes.

[Kickstart]

Hi

Sounds like a lean mixture off idle, so above suggestion well worth checking (although it may well be a slide carb which would count out that problem).

Other thing to check is for water in the carb. Have you just switched onto reserve?

All the best

Keith
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[Matt Read]

Yeah it is a slide carb. I did go to reserve tank recently. So maybe I should have another look at the carb. What is the best method for getting rid of water, if there are droplets in difficult to reach areas??

[Kickstart]

Hi

Petrol is lighter than water, so the water goes to the bottom of the petrol tank and gets dragged in when you use reserve. And when it gets into the carb it goes to the bottom of the float bowl where it will be picked up by the main jet. Hence when you open the throttle the bike draws fuel through the main jet and instead gets some water.

First thing to try would be to just turn the petrol off and undo the drain screw on the carb to get the water / petrol out (try and catch it in a container). Then tighten the screw again and turn the petrol back on.

All the best

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

[Matt Read]

Makes sense, thanks for the help. Will have to wait until daylight before trying it out and will probarly drain the fuel tank first. Thanks for the advice.

Matt