Carburettor Needle

HD · World Chat Champion Joined: 16 Dec 2009 Karma :

Okay so I have sorted out my bike after many months and its running Mr. Green

My dad reckons he put the little washer thing on the needle on the fourth notch down when it is supposed to be third (or vice versa, cant remember).

What will this do to the bike?

As at the moment I haven't ridden it properly (two weeks til my CBT) but it does seem to be running odd. It hasn't been taken up the round or round the block so it probably was never fully warm but it just seemed to do the 'two stoke crackle' sort of thing. Its hard to explain but when they are cold and they seem to sort of 'stuggle'... You know what I mean Wink

We probably will end up changing it when we can get hold of the correct* throttle cable but what will it do for now?

* I have tried 2 different throttle cables and neither fit. Same with the clutch ones :/
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Rusty '02 Vito Camper + CBR600F3

Bikeless · World Chat Champion Joined: 27 Jun 2008 Karma :

It will either be slightly richer or slightly leaner depending on which groove he has put it on,the lower the groove,the richer(raises needle)and vice versa.It shouldn't make too much difference as the main jet is still the same unless of course you have changed that aswell.

Ask Kickstart,he'll fill you in with all the info about needle height,float height,jet sizes,part fuelling etc.

HD · World Chat Champion Joined: 16 Dec 2009 Karma :

Changed the main jet as I bought a new exhaust (my standard one was knackered) but jetted it to what PJ Motorcycle Engineers recommended. So haven't had a proper warm run yet to see what its like but of course I will be running it in so its harder to tell exactly what it is like.

On a side note, it does seem to run better. Not sure if it is the exhaust but it now seems to have a powerband. Never did before. Would that be down to just the exhaust or the fucked clutch, piston, cylinder, carb, airbox?
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Rusty '02 Vito Camper + CBR600F3

Vincent · Banned Joined: 16 Oct 2006 Karma :

The jet needle has to be in the right position in relationship to the "cutaway" on the carb slide for the optimum fuel/air mixture at the right time. If it's wrong you would suffer poor pick up and/or bogging down. If the bike has standard carb, jets, bore and exhaust, just stick the needle clip on the manufacturers recommended groove.

The powerband should be noticable on any sports two stroke, if you didn't have one before there must have been something very wrong.

HD · World Chat Champion Joined: 16 Dec 2009 Karma :