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sync the carbs

Old 01-16-2013, 11:06 AM
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sync the carbs

I'm bbaaaacckk! With another question that is just burning a hole in my skull. Has anyone ever checked to see if the linkage between the two carburetors is set so both carburetors are "leaving" at the same time? On other machines I've had it was part of the tune to set both after getting idle sync set. Slowly run the rpm's up to 3000 to see if both are synced at higher rpm's. Just curious. Will check it out myself and come back. Thoughts or admonishes?
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Old 01-16-2013, 11:13 AM
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Originally Posted by twist View Post
I'm bbaaaacckk! With another question that is just burning a hole in my skull. Has anyone ever checked to see if the linkage between the two carburetors is set so both carburetors are "leaving" at the same time? On other machines I've had it was part of the tune to set both after getting idle sync set. Slowly run the rpm's up to 3000 to see if both are synced at higher rpm's. Just curious. Will check it out myself and come back. Thoughts or admonishes?
With the stock intake configuration this will be all but impossible due to the different length velocity stacks.

With the aftermarket billet stacks it works fine.
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Old 01-16-2013, 11:36 AM
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Originally Posted by 8541Hawk View Post
With the stock intake configuration this will be all but impossible due to the different length velocity stacks.

With the aftermarket billet stacks it works fine.
so, are you talking about aftermarket velocity stacks that are the same dimensions or is it something to do with the bell shape or the measurement of the outside bell from the carb intake, distance from outside of bell mouth to where it connects to intake? Am I making sense?
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Old 01-16-2013, 11:51 AM
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I believe Hawk is talking about these.....
sync the carbs-billet-v_stacks.jpg
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Old 01-16-2013, 12:51 PM
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Yes those (or the Mori units they are copies of) are what I mean.

The simplest answer would be that it is not so much the shape but because they are the same length.
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Old 01-16-2013, 03:58 PM
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Originally Posted by Upland111 View Post
I believe Hawk is talking about these.....
Attachment 15027
very nice pieces! I was asking more about why the aftermarket stacks are different. Obviously if it's length that makes the difference then is it because they are the same length? Is it about the material used?

On antoher note, I did try to sync the carbs at 3000 rpm and found it frustrating. After re-syncing the carbs that annoying hitch that's been ******* me has gone, no more hiccups at 3500 to 4000rpm. Took the vtr out after sync trying to make it hitch and couldn't get it to do it anymore. This engine is very particular about synced carbs it seems. One thing that surprised me is that right after I set the carbs the bike stalled at lights several times. Like it does when the kick stand is deployed and it's put into gear, but only at idle. That cleared up after the bike got good and hot and didn't come back.
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Old 01-16-2013, 04:08 PM
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I usually turn my idle screw up to around 2krpm or a little higher when I sync.
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Old 01-16-2013, 05:24 PM
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Interesting, I usually sync at Idle 1200+/-100 rpm. I feel that even with V-stacks that at higher revs, while stationary, the airflow into the carbs is most likely not equal and thus doesn't give me a accurate indication of synchronization. I could be totally wrong on this but from what I have found, even when I slowly increase revs up to about 4G there is not enough differance between the carbs to bother adjusting differently at idle. This could be true just based on my set-up, and may be completely differant for others, depending on many factors such as type of filter, carb set-up and engine state of tune, etc. etc.
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Old 01-16-2013, 05:35 PM
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Originally Posted by 7moore7 View Post
I usually turn my idle screw up to around 2krpm or a little higher when I sync.
I like your idea. I really want to make a tool for the air screw, too. Bike is running fine! I love this bike!
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