My set up Mollossi 70cc head Crank seals Techigas next-r exhaust 4.0g rollers 17mm carb 90 jet Stage 6 water pump Chrome cover Sorry if this as already been covered but I couldn't find anything Well.... it all started when the bike was running abit lean so I changed the jet from 86 to 100 but after I did that it started spluttering loads of fuel can out of the over flow (the flot had stuck) so I re cleaned the carb replaced seals put a new 90 jet in instead of 100 reset flot and took it out. It was running ok but after 5mins or so it would get to about 25mph and start spluttering agen like it's going to cut out ? It ticks over fine and runs fast up to 25mph but then suddenly starts spluttering at 25 n nearly cuts out Any help would be great
check for airleak around the carb inlet / reedcase / airbox to carb , what needle setting have you got on the slide needle you could find you need to tweek the slide needle setting one notch down to richen the 1/4 throttle to 3/4 throttle fuel feed flow
I will check for a air leak today but as far as I know it should be ok. It's on 1/4 turn out , Cheers I will try this today an Tell you know how it gos
I tryed messing with to screw and it did make take of better but as soon as it got to 25mph started spluttering agen ?
inside the carb is a slide, in that slide is a long needle. the slide needle has some little rings on it usually three to four rings , there is a clip that fits on these little ring cutouts. you tend to find they are usually set with the clip in the upper to most ring slot or the slot one down from the top, you need to check what setting that ring clip is on. the slide needle denotes how much fuel is allowed to flow into the carb when the throttle is 1/4 turn to 3/4 turned , midrange throttle, if the slide needle has the clip fitted to the upper most setting it means the fuel flow in the throttle range from 1/4 to 3/4 open is somewhat lean. if the needle clip is on the bottom most clip setting it means the slide needle is set to the most richest setting ie it allows the most fuel between the 1/4 to 3/4 turn marks on the throttle. your idle jet and mixture screw denote the throttle idle at 0 - 1/4 throttle ( aka idle setting ) your slide needle denotes the fuel flow rate when the throttle is past 1/4 and no more that 3/4 open ( mid range setting ) your main jet denotes the amount of fuel that can be drawn into the engine BUT only when the throttle is wide open . at 25mph your around 1/4 onwards open on the throttle so in theory any fuel problems would be either main jet to large ( not the case here) or the slide needle setting is a little on the lean side, ie as the needle travels upwards in the mainjet its restricting the amount of fuel allowed to enter the engine. a richer needle setting would let more fuel into the carb and engine and you should see an improvement. if your unsure how to do this you can always pop bike into a shop and have them set and check the carb settings , however they will charge you labour costs as they have to take the scooter for a couple of rides while tweeking the carb and adjust it settings.
Back .... so I changed the needle stoped running altogether. I then tryed all settings no luck , so I changed the jet back to 86 size wouldnt start still. I then fitted a open air filter I had , started running agen so I tried setting it up and went Round the block..., so it ran but now it's just very boggey , if you put the throttle on is sounds like it will cut out then u put it on agen straight after and it starts getting speed but intermittently juddering to do it any ideas ????
Your jetting is way off by the sounds of it, use a proper airbox, and sort your jetting out a bit. Couldn't give you any idea which way to go without riding it.
Atm pal ave got it set up on a 86 jet open filter and it runs but if u full throttle it sound like it's cutting out but if u build the revs it starts to go but when u get to full throttle it starts cutting out agen any ideas I tryed up jetting and it just never started
