Bike dies on throttle

[fasttom]

Bike idles like a Swiss watch but dies as soon as you touch throttle, any ideas ?

I have re-built carbs including doing float bowl seals and made all the necessary adjustments I.e float levels, mixture settings etc. What would be causing this symptom ?

Cheers Tom

[tigerclaw]

That would mean that the bike is leaning out when you open the throttle (open throttle = more air = bad air to fuel ratio and the bike dies) so my first guess would be blocked main jets but I assume you made sure they are clear and you didnt get any dirt or excess silicone into the bowl when you closed it up. That would lead me to guess that its either float level or mixture setting is out (probably mixture setting) but unfortunately I am not clued up enough to tell you how to sort that out besides the fact that I know that the mixture screws are supposed to be 2.5 turns out as a starting point (ie turned fully in and then undo them 2.5 turns) - hope that gives you some direction

[tigerclaw]

Also a bit of a guess but did you open the slide covers and did you make sure you didnt cover their vaccum holes accidentally with the rubber insert when you closed it, wondering if the slides are not lifting? And then just a bit of a disclaimer I am rebuilding my bike for the first time but I am learning a lot while I am going so my suggestions are based on what I have found out so far (as a newbie) rather than "years of experience" etc so I could well be wrong but seems we're up to the same thing :)

[fasttom]

Hmm strange looks like carbs will have to come off again. They have been on and off more times than I care to remember no wonder fuel injection came about! Mixture settings were adjusted to 2.5 turns out on carb rebuild and I was careful to ensure jets were clear......

[fasttom]

I have taken carbs off the bike and have ensured mixture settings are all at 2.5 turns out from closed. I have had all float bowls off to inspect given all jets a good dose of carb cleaner and blasts of compressed air down all passages. Float heights are correct as bike was running like a charm before I removed for new float bowl seals. Reassembled on bike and bike idles perfectly but as soon as throttle is touched it dies. My battery is pretty knackered and I have had on trickle charge just to get enough juice to start bike, would a knackered battery cause this symptom ?

[Tornado]

You might try turning the pilot screws in about a turn on each carb... And see how that affects it before pulling it apart again.

[fasttom]

Not sure access is all that easy to adjust mixture settings with carbs on bike will have a look see if it can be done easy enough

[Neosophist]

Not sure access is all that easy to adjust mixture settings with carbs on bike will have a look see if it can be done easy enough

Its easy to change the mixutre screws with the carbs on, if you want to fine tune it you need to do it with the bike running.

tbf 2.0 / 2.5 shouldnt make a great deal of difference.

id stick with two turns.

did it work before you messed with the carbs?

also a knackered battery will cause all kind of shit.

[fasttom]

Bike was running nicely before I changed float bowl seals. I will adjust to 2 turns out and give the battery a bit more juice for a couple of hours and see what's what. The battery is pretty past it but holds enough to get it started onto idle one it has had a bit with a trickle charger

[Neosophist]

Bike was running nicely before I changed float bowl seals. I will adjust to 2 turns out and give the battery a bit more juice for a couple of hours and see what's what. The battery is pretty past it but holds enough to get it started onto idle one it has had a bit with a trickle charger

thats no good. it will destroy your reg/rec too if you use a knackered battery.