2001 speedfight2 100cc problems

Hi all this is my 1st post on this site and I'd like a bit of advice if possible?

I have recently bought myself a speedfight2 100cc moped, it hasn't been used for a while (atleast a year) by the previous owner.

It hasn't even done 3,000 miles yet that's how little it's been used, the problem is, every now and then it will break down on me, for example the first time it happened was after I cleaned it, I believe it was last Monday, I went to start it with the kick start and it failed to start, about 10 kicks later it fired up yet every time I touched the accelerator it bogged down and cut out, left it running for a few minuets whilst I made a brew and it was fine.

The next time it happened was on my way to work, was riding down a duel carage way at 40 and hit a sunken man hole cover, emidiaty the bike began to bog when trying to accelerate, I pulled into a near by bus lane and left it ticking over until the bogging stopped and then it was fine.

Thought to myself that it's an air problem so Saturday I decided to open the air box and check the filter, to my surprise it was drenched in thick black oil so cleaned it out and put it back in and the bike ran better than it ever has whilst I've had it, but last night on my way home for no reason the bike cut out, started it up again and it ticked over but bogged every time I tried to pull off so got frustrated and walked it to my mums where I checked the filter again, nothing wrong with it but still no pull off, stayed the night and this morning I started it up and it reved but was smoking like mad, left to go to mine but it didn't seem right, it was bogging ever so slightly but enough to get me back and then it was back to normal again, so is there anything that anyone can suggest as to what the problem might be rather than me potentially wasting money putting it into a garage when I could possibly fix it myself

Will apologise for the length of this post but I know details are vital in potentially diagnosing the problem

Mr J L Millbourn

I'm having a problem kinda close to yours so I have a 49cc moped Chinese and every time I give it gas it'll bog down till I let off or it'll cut off and the only way I could fix that is if I take the airbox off and covering the carb hole where the air filter goes and it'll only rev up like 65% of what it should go and only hits 20mph so if anyone could help me also it would be much appreciated thank you.


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I'd check the carb settings and the piston rings and barrel for scores it might be losing compression I've got the 307 wrc version mine was bogging and struggling to start turned out to be the piston and barrel

Check for evidence of oil in the transmission and flywheel casings. If oil has found it's way there, the crankcase seals are shot. Check for air leaks in the inlet manifold and drain the carb float bowl down, as water in the fuel could cause the bike to cut out. Whip the cylinder head off and see if the barrel is scored - it's quite common on Peugeots, as they run at about 33:1 oil ratio and that's quite lean, they run so much better with 2% oil added to the fuel (giving 20:1 ratio overall).

I've adjusted my oil pump so the mark is just over and also put a cap full in the petrol tank when I fill up and give the bike a little wobble

CamTheHardWorker said:

I'm having a problem kinda close to yours so I have a 49cc moped Chinese and every time I give it gas it'll bog down till I let off or it'll cut off and the only way I could fix that is if I take the airbox off and covering the carb hole where the air filter goes and it'll only rev up like 65% of what it should go and only hits 20mph so if anyone could help me also it would be much appreciated thank you.

I suspect that your scooter has a diaphragm carb, a copy of the Keihin design. Whip thte top off the carb and look for evidence of any pinholes or splits in the diaphragm and general crud in the carb.