carb sync
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Squid
Joined: Jul 2013
Posts: 57
From: Summerville, SC
carb sync
So I made one of the manometers. Like found on here (Thanks). I am unsure as to (after a search) find the answer Im looking for. After syncing at a slightly elevated idle, then hold the throttle to about 4-5k rpm, its pretty far off balance. is this normal? and if not, how to correct? i cant get idle and elevated rpms to match well. thanks.
Senior Member
Superstock
Joined: Apr 2013
Posts: 466
From: SF Bay Area
I just re jetted and synced and find the same thing. At 1200 idle, the fluid in the tubes is even (very jumpy but even) adn when raping the throttle the front vaculme beceoms stronger. If I slowly roll on it goes back and forth until about 4k then the front raises a little. The bounciness goes away once some throttle is applied. I'm not sure if this helps at all but it's what my bike is doing.
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Squid
Joined: Jul 2013
Posts: 57
From: Summerville, SC
I balanced it more even at close to 4k instead of idle. My mind says it would be better to have even pressure when Im getting into a load and less uneven as the rpms climb. Compared to setting them even at idle and be VERY far off as te rpms climb. Whats your thoughts on that?
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MotoGP
Joined: Apr 2006
Posts: 4,402
From: Kempner, TX
So I made one of the manometers. Like found on here (Thanks). I am unsure as to (after a search) find the answer Im looking for. After syncing at a slightly elevated idle, then hold the throttle to about 4-5k rpm, its pretty far off balance. is this normal? and if not, how to correct? i cant get idle and elevated rpms to match well. thanks.
Sync them at idle.
Thread Starter
Member
Squid
Joined: Jul 2013
Posts: 57
From: Summerville, SC
Not trying to challenge you. Im just looking to get a better understanding of how this bike works. With that being said, why wouldn't getting more even pressure in the meat of the power be better for performance? Or is there any good documentation online that i can get a good insight on the hows and why's of these carbs? Thanks man. i appreciate it.
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MotoGP
Joined: Apr 2006
Posts: 4,402
From: Kempner, TX
In a perfect world ...you would want air/atomized fuel flows matched in both carbs through the air cleaner, intake tract, carb, manifold, head and valves at all RPM and all vehicle air speeds.
Reality is ...it aint happening with any close to stock,, and likely not ever no matter how much R&D you put into it.
All that said........ My bike is pretty close on vac draw from 1800 where I set sycn to say a 3-4k steady RPM check
Reality is ...it aint happening with any close to stock,, and likely not ever no matter how much R&D you put into it.
All that said........ My bike is pretty close on vac draw from 1800 where I set sycn to say a 3-4k steady RPM check
Senior Member
Superstock
Joined: Apr 2013
Posts: 466
From: SF Bay Area
Follow up question, should I raise my idle to 1800 to set the sync then lower it back to 1200 after the sync? I have been trying to sync at 1200. I did put 50 pilot jets in the lines to calm down the movement of fluid a little.
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MotoGP
Joined: Apr 2006
Posts: 4,402
From: Kempner, TX
1200 is on the low side of "standard" and I personally like mine at about 1400~1500
Thread Starter
Member
Squid
Joined: Jul 2013
Posts: 57
From: Summerville, SC
In a perfect world ...you would want air/atomized fuel flows matched in both carbs through the air cleaner, intake tract, carb, manifold, head and valves at all RPM and all vehicle air speeds.
Reality is ...it aint happening with any close to stock,, and likely not ever no matter how much R&D you put into it.
All that said........ My bike is pretty close on vac draw from 1800 where I set sycn to say a 3-4k steady RPM check
Reality is ...it aint happening with any close to stock,, and likely not ever no matter how much R&D you put into it.
All that said........ My bike is pretty close on vac draw from 1800 where I set sycn to say a 3-4k steady RPM check
Senior Member
MotoGP
Joined: Jul 2010
Posts: 3,871
From: Phoenix, AZ
I set my idle up higher for sync (1800-2000) then drop it to around 1300 for riding. This isn't based off of anything other than the manual saying to take measurements at idle and a higher rpm and sync them in the middle of that. Take that with a grain of salt.
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