not starting after emptying and re-filling tank

i highly recomend you dont take out the jets unless u plan on replacing them, spraying carby cleaner down then should be fine, shine a torch in there and if looks clean enough id leave it.

when you took the float bowls off, how clean was it? if it was clean no scum or watever then the carbies should be ok...

if you do/have unscrewed the jets, they only need to be screwed in just finger tight, dont screw them in tightly at all!!!

just an afterthought, is the current fuel regular unleaded or some form of premium? i had a similar problem with mine, that was caused by using premium fuel, if you have premium in, definately empty the tank and put regular in, might just solve your problems?

 

You can have as many post as you want Simon.

 

How soon are you trying to turn the choke off?
Is it possible the bike just hasnt yet warmed up enough to keep running?

 

Sounds to me like your idle mixture screws are too far in.
Did you 'screw' with them aswell? <!-- s:lol: --><img src="{SMILIES_PATH}/icon_lol.gif" alt=":lol:" title="Laughing" /><!-- s:lol: -->

 

Mine stays on choke about 45-60 sec. then I let it idle about the same amount of time, then I go.

 

is it possible that some gunk is clogging the fuel line somewhere?

The choke cuts air, meaning that the bike runs richer -> This would lead to a more optimal fuel / air mixture if a fuel line's blocked and it's normally running lean.

(ie. running lean + choke = good fuel mixture)

 

the choke does exactly as its name sugests - chokes the engine (reduces the amount of air going into the mixture).

if your bike's running lean (as engines do when they're cold) then using the choke will make it run better.
This is also why a properly tuned vehicle will run like crap if it's warmed up and the choke's on - it'll be running rich.

 

You mean the idle stop screw?
Or the carb balance screw between the 2nd & 3rd cylinder?

Regardless... it sounds like you've been tinkering where you shouldn't have. <!-- s:rofl: --><img src="{SMILIES_PATH}/icon_razz.gif" alt=":rofl:" title="Rofl" /><!-- s:rofl: --> <!-- s:lol: --><img src="{SMILIES_PATH}/icon_lol.gif" alt=":lol:" title="Laughing" /><!-- s:lol: -->
First thing to do is to get it running, then find out if it's running lean or rich my playing with the choke and finding a point that it sounds like it's running properly. If the engine is warm, and the 'perfect point' has the choke still engaged then the engine is running lean as has been suggested before. If the bike just ever so slowly dies when you disengage the choke, then try increasing the idle speed and see if it stays running.

I'd start off by making sure the idle mixture screws are set properly (3 turns out), then getting it running, and following the steps above. It's all just one big balancing act to get everything running smoothly. <!-- s --><img src="{SMILIES_PATH}/icon_cool.gif" alt="" title="Cool" /><!-- s --> <!-- s:roll: --><img src="{SMILIES_PATH}/icon_roll.gif" alt=":roll:" title="Rolling LoL" /><!-- s:roll: -->

 

Oh noes! <!-- s:???: --><img src="{SMILIES_PATH}/icon_confused.gif" alt=":???:" title="Confused" /><!-- s:???: --> <!-- s --><img src="{SMILIES_PATH}/icon_sad.gif" alt="" title="Sad" /><!-- s -->

Your gonna need to hook it back up to a set of vacuum gauges else it'll never run smoothly at this rate. Carby balancing is not really something you can just guess either... and i'd strongly advise against using the ball-bearing method.

What happening right now is that cylinder 1 & 2 are receiving either too much or too little fuel, and 3 & 4 are getting the opposite. Your poor bike is rather confused right now. You can attempt to fix it by doing it by ear, but unless you really know what your aiming for... i'd be finding someone with vacuum gauges.

 

Are you sure you adjusted the balance screw? I mean, it needs a screwdriver to manipulate, the idle mixture is just a dial that you can turn with your hands..

However it would cause issues not unlike what you are describing here.

Regardless, perhaps you should take the jets out and manually clean them. Not too hard to do, just be gentle.