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Post by martynbrinton on Apr 20, 2006 7:37:13 GMT
this is real pain.
The bike starts fine in the morning and off I go, until the first set of traffic lights. The bike dies. It starts (fairly) ok, but then opening the throttle just kills the engine. I have to spend about 10 mins starting it and teasing the throttle up until it eventually 'bites' and can accelerate away with me on it.
I've read other threads and have tried:
- adjusting fuel/air mixture now at 3 turns out ( tried various settings )
- checked the rubber thingy in the carb is seated
- checked spark plug ( very black which looked like too rich)
- adjusted idle screw
could there be muck in the jet? Going to try and open the carb up this weekend. Will also check rollers, but not sure how this can cause the problem.
any more hints greatly appreciated.
ALSO! Can you disable the electric start safety option connected to the bike stand? I have to keep taking the bike on and off the stand to get the electric start to fire - looks like it thinks the bike is always off stand.
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Post by ally1756 on Apr 20, 2006 11:35:03 GMT
defo a carb problem, are u using a freeflow, if so remove it, put your mixture screw to 2.5 turns out and then tighten your idle screw up, then check your autochoke. ally  |
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Post by cumbria123 on Apr 20, 2006 21:24:42 GMT
I had a similar problem on my QT-11. I tried allsorts to Fix it. In the end I resorted to asking a local bike dealer abouthe carbt it, and he advised me not to have the mixture too rich. He said that "because the bike was a four stroke, and not 2 stroke it need only have the mixture screw wound out 1 and a half turns."I tried this and hey presto it worked! The bike ran better than it has ever done, and on checking the spark plug after a few miles it was a nice golden brown colour. I have since tweeked the carb mixture screw a little richer by an eighth of a turn and found the ideal spot for my bike. Be careful not to make the mixture too lean as this could have a disasterous effect on the valves, but hey its maybe worth a try. Good luck with it. I just love these crazy chinese scoots!!!!!  |
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Post by dmilo on Apr 20, 2006 23:09:37 GMT
hi all
Is it 2.5 or 1.5 turns out I dont wanna run to lean Is any body sure
Ive always heard and read here 2.5 turns out until cumbria 123
dmilo
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Post by ally1756 on Apr 20, 2006 23:34:31 GMT
i might try 1.5 i think im burning rich anyway ally |
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Post by cb50j on Apr 21, 2006 3:59:59 GMT
1.5 give or take a quarter turn according to service manual........
................ #sprint#
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Post by martynbrinton on Apr 21, 2006 7:04:19 GMT
ok, I'll try 1.5 also and see how it goes.
This is all new to me, but I've obviously misunderstood this screw. I thought turning out let more air in, thereby making it leaner - more air to fuel ratio, so I've always tended to turn out more as my spark plug was quite black/sooty. oh well, live & learn!
thanks for the advise; appreciated as always.
Martyn
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Post by enu06 on Apr 21, 2006 7:12:25 GMT
What is the weather like when this happens? I had exactly the same thing happen on 2 cars, a Suzuki GSX 750F, and now this scoot. As you say, start off go short distance and stall. I know exactly what the cause is and how to cure it. Ready? CARB. ICEING! A ring of ice forms round the metal air intake on the carb and has a choking effect, usually on cold damp foggy mornings, or as up here (Shetland) on higher ground, cold and damp. The cars were easy fixed, just turned the air intace to winter to draw warm air off the manifold, The Suzzy got carb heaters fitted ( they knew of the problem and fitted them as standard on other models,) But quite how to fix it on the scoot? well I dont know! All I've done so far is leave it for a minute or so, and it cleared, the heat off thengine at standstill is enough, also took the restrictor out of the airbox. If it does it agian I'm not over worried as I know its not serious, and only happens when the conditions are right, or wrong, if you see what I mean! Hope this helps.
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Post by enu06 on Apr 21, 2006 7:36:13 GMT
Als, the term 'air screw' is abit misleading, it really guverns the fuel allowance it the air sream through the carb, Basicly, the piston going down, inlet valve open, draws air in to the chamber, but the carb body is designed in such a way as to cause a venturi effect, giving it more of a rush, think of it as the prifile of 2 aircraft wings, top to top. now introduce a valve (throttle control) that allows us to increase or decrease the amount of air allowed through. Now introduce a jet to let in the petrol into the venturi chamber, at the right ratio of air to petrol, add a spark in the piston chamber at presisley the right time and wallah, BANG, you have ignition. Its this screw that you turn in or out to fix the amount of petrol going in, so turning it out lets more in (rich) turning it in lets less in (lean), its up to you to find that elusive happy medium. That is roughly how a carb works then, O.K.?
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Post by martynbrinton on Apr 21, 2006 9:14:44 GMT
that's a great explanation. thanks!
weather is actually fine here in Essex when that happens to my scoot, so not sure about the icing theory. Always first thing in the morning though. Last time I took the scoot for a spin in the evening and it was perfect - first thing in the morning, throttle problem. i think it doesn't like the idea of going to work!
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drzoom
Forum Master
Posts: 187
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Post by drzoom on Apr 21, 2006 13:07:33 GMT
carb icing is easily and cheaply fixed. Just buy a bottle of Silkolene ProFST. You add a very small amount to the tank every time you fill up. Not only does it prevent carb icing but it helps clean the engine. I use it all year round.
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Post by ally1756 on Apr 21, 2006 17:07:35 GMT
ALSO! Can you disable the electric start safety option connected to the bike stand? I have to keep taking the bike on and off the stand to get the electric start to fire - looks like it thinks the bike is always off stand. dont use the side stand its not really safe, use the main stand! |
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Post by BillyGreen1973 on Apr 21, 2006 17:28:28 GMT
The carb description is spot on, except the 'air screw' description bit is completely opposite. It does control the amount of air in the mixture, the amount of fuel is controlled by the jets (iddle and main), and the needle valve.
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Post by ally1756 on Apr 21, 2006 17:48:37 GMT
ok the 1.5 doesnt work - i just tried it and it kept cutting out, 2.5 for me! ally |
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Post by dmilo on Apr 21, 2006 19:14:45 GMT
Hey all,
put in a new spark plug in a few weeks ago did 300 miles on it.
Then brought the plug to an automotive store for assistance
the two men own harleys and read the plug and said it was the perfect color tan starting form . My setting on the carb has been 2.5
they said dont touch it.
dmilo
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Post by martynbrinton on Apr 22, 2006 9:54:32 GMT
carb icing is easily and cheaply fixed. Just buy a bottle of Silkolene ProFST. You add a very small amount to the tank every time you fill up. Not only does it prevent carb icing but it helps clean the engine. I use it all year round. couldn't get this from my local halfords. is it the same type of stuff as redex ( which seems to be a petrol/carb cleaner). is it ok to use redex? |
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Post by Macrofeet on Apr 22, 2006 16:42:00 GMT
i put some redex in mine only the smallest 99p bottle from halfords
no problems
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Post by martynbrinton on Apr 24, 2006 17:17:46 GMT
UPDATE: well I decided that I'd take my screwdrivers with me and true to form, 1st set of lights it died and when started, throttle would kill the engine. i played around for the next 10mins with the mixture and idle screw untilI got it running and the throttle was fine. For the last few days, no problems  Only thing I have is that as I pull away, it starts to accelerate nicely, then the revs very briefly drop and then it kicks in - I can live with this. once again; thanks for all the advice. |
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