hardleydavidson Posted September 29, 2014 Posted September 29, 2014 Hi,I've been having no end of trouble with my bike, it seems as if it only uses the fuel in the carb as it runs then dies, runs then dies, of course it could be that there's not enough fuel getting in or it's too lean but I've spent a good few months trying to tweak the mixture and I just can't cure the problem.It's a 50cc 4-Stroke with a PZ19 manual choke carb, I recently fitted a K&N style filter, do I need to up the size of the main jet? The one on it is stock.I've also dremelled the restrictor tab from the carb bowl. Quote
eastanglianbiker Posted September 29, 2014 Posted September 29, 2014 yes you will need to increase the size of the main jet to allow for the extra air the air filter is drawing in how much will you need to increas it by is guesswork prety much a case of trial and error untill you find the right size you might also need to raise the needle one notch if i ts adjustable Quote
hardleydavidson Posted September 29, 2014 Author Posted September 29, 2014 Great I'll give the needle change a go and order a pack of jets Quote
Mr Fro Posted September 29, 2014 Posted September 29, 2014 If it's doing a run - conk out cycle then I'd be looking at fuel delivery to the carb - blocked filter, iffy tap, kinked hose etc... Quote
Tango Posted September 29, 2014 Posted September 29, 2014 If it's doing a run - conk out cycle then I'd be looking at fuel delivery to the carb - blocked filter, iffy tap, kinked hose etc... + check the float height....... Quote
hardleydavidson Posted September 29, 2014 Author Posted September 29, 2014 Yeah I thought that too but been over it with a fine tooth comb, blew out all the hoses and the fuel tap, fuel filter is clean too, float height is correct.I did have to replace the fuel tap a while back as the handle part snapped of under my manly grip, I was wondering if the diameter of the exit tube is as big as the old one, a smaller diameter would deliver less fuel but it looks roughly the same. I'm running out of ideas and I need to get it MOT'd next month. Quote
Mr Fro Posted September 29, 2014 Posted September 29, 2014 It's a fiddy my friend, so long as the fuel hose has an internal diameter, you'll be fine. Bob's right, if you're getting fuel to the carb then the only thing it could be is the floats - they'd have to have quite a gap to do the sort of thing you're describing. Maybe knock them up a couple of mm and see what happens. Quote
Tango Posted September 29, 2014 Posted September 29, 2014 It's a fiddy my friend, so long as the fuel hose has an internal diameter, you'll be fine. Bob's right, if you're getting fuel to the carb then the only thing it could be is the floats - they'd have to have quite a gap to do the sort of thing you're describing. Maybe knock them up a couple of mm and see what happens.Or the needle valve on the float is sticking...... Quote
Mr Fro Posted September 29, 2014 Posted September 29, 2014 Or the needle valve on the float is sticking...... (In a high, squeaky voice):Mimminy, mimminy - ooh, could be the valve - mimminy mimminy.Smart arse. Quote
hardleydavidson Posted October 6, 2014 Author Posted October 6, 2014 Hi,Well I've readjusted the float level (it was out), upped the needle by one notch and now it seems much better. The proof will be on the way home tonight as it's all uphill.Thanks chaps Quote
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