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what is the tube between carbs needed for on 650

5K views 7 replies 4 participants last post by  Delson 
#1 ·
Is it needed? I am sure it is there for a reason. can I shorten it? The bike has K&N filters, jetted, pipes and the ais was removed.
 

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#2 ·
The tube is connecting the ports used to sync the carbs. There is normally a cap over them. You can shorten the tube without any issues. Just remember the ports need to be capped off or connected like yours or you will have a major vacuum leak.
 
#4 ·
uhmmm....... !!! you do not want your two intake ports tied together like that

when one cylinder is on the intake stroke the other is on the exhaust stroke. That will be trying to pull air from both carbs at the same time.

Those ports are for attaching a vacuum gauge, they are suppose to be plugged otherwise, not cross linked.

Maybe there is something in that hose plugging it, if not get the caps from any auto parts store and cap them proper.
 
#6 ·
You're talking about the brass tubes in the intake manifold? Or about that flexible black tube that comes from between the carbs and goes to the back of the air filter box?
If it's about the black one, this is the carb breather. Let it this way and don't cap. In case of stucked float bowls, you will notice some gas leaking from this tube.
 
#7 ·
It is the black tube in the foreground. The larger one in the back is the connection to the tank...tank is off. I did have a question about the tube between the carbs themselves..it was cut. I believe it went to the breather which is now gone because I have K&Ns. It is open, not connected to anything...I just thought this was ok. I cleaned the carbs, floats were in great shape...and to my surprise...the carbs were pretty clean and no clogs. I'll keep an eye on it for dripping now that I know what it is for..thanks.
 
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