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Carb Sync question...

Old 07-06-2010, 09:33 PM
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Carb Sync question...

So I did a carb sync last weekend.
I used a home made manometer, and it worked great...idle only bounces now maybe 50rpm
My only question is...Since they wont sync perfectly at both idle and 4000 rpm...am I better off synching at idle, at 4000 rpm, or somewhere in-between?
Thanks,
Mike
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Old 07-07-2010, 07:27 PM
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Sync at idle. Just make sure your idle speed is right.
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Old 07-08-2010, 03:50 AM
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It should be good...I originally synched at ~1200rpm, then after adjusting the throttle screw on the rear carb, I had to raise the idle a little bit.
So I wound up finishing the sync at ~1100-1150rpm...which is usually where I keep it.
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Old 07-08-2010, 05:28 AM
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Sounds good. For what it's worth, some guys have mentioned problems with dying at idle if under 1200. I'm where you are currently at and haven't had a problem yet.
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Old 07-08-2010, 05:52 AM
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if your idle is too low, whaterver rpm that is, you will not get sufficient oil flow through your engine. You should set it to spec.
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Old 07-08-2010, 10:45 AM
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True true. That's why I just run 5w20. Plus it's easy to find for cheap!
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Old 07-08-2010, 12:34 PM
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I have read other posts about people having problems with their bikes dying at a lower idle setting, but I never had that problem since I got the bike 7 years ago.
Also, I would figure that 50-100 rpm shouldn't make that much of a difference as far as oil flow, but to be honest, I never really thought of that...so you bring up a good point, Resident.
I just always thought the bike sounded smoother and happier at 1100rpm.
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Old 07-08-2010, 12:41 PM
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Just a thought, you can get the oil light to go off by cranking the starter. Don't know what rpm that happens.
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Old 07-08-2010, 06:41 PM
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Was just kidding about the oil... before someone attacks me.
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Old 07-08-2010, 07:32 PM
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Originally Posted by superh1998 View Post
I have read other posts about people having problems with their bikes dying at a lower idle setting, but I never had that problem since I got the bike 7 years ago.
Also, I would figure that 50-100 rpm shouldn't make that much of a difference as far as oil flow, but to be honest, I never really thought of that...so you bring up a good point, Resident.
I just always thought the bike sounded smoother and happier at 1100rpm.
Well 1100 rpm is still in spec as the spec is 1200rpm +\- 100 rpm
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Old 07-08-2010, 08:38 PM
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Originally Posted by 8541Hawk View Post
Well 1100 rpm is still in spec as the spec is 1200rpm +\- 100 rpm
Thanks for the info, Hawk...I hadn't had a chance to check the manual yet. I knew it was 1200, but I forgot about the +/- 100.
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Old 07-08-2010, 08:41 PM
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Originally Posted by 8541Hawk View Post
Well 1100 rpm is still in spec as the spec is 1200rpm +\- 100 rpm
If it is truly set to 1100, I do not think that our tachs are that accurate down low. I tend to play it conservatively and would set it to 1200. That being said, I have not looked at mine in a while.
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Old 07-10-2010, 04:28 AM
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Originally Posted by superh1998 View Post
So I did a carb sync last weekend.
I used a home made manometer, and it worked great...idle only bounces now maybe 50rpm
My only question is...Since they wont sync perfectly at both idle and 4000 rpm...am I better off synching at idle, at 4000 rpm, or somewhere in-between?
Thanks,
Mike
hey mike, what do you mean by," it won't sync perfectly"?
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Old 07-10-2010, 05:55 AM
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At idle, the fluid is level on both sides of the manometer.
When I go to 4000 rpm and hold it there, the fluid rises on 1 side.
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Old 07-10-2010, 01:47 PM
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Originally Posted by superh1998 View Post
At idle, the fluid is level on both sides of the manometer.
When I go to 4000 rpm and hold it there, the fluid rises on 1 side.
I never tried that, but it would seem that if they're sync'd, that wouldn't happen. Maybe someone who knows will be able to comment.
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Old 07-10-2010, 01:56 PM
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just a thought, the two cylinders require different jetting for a reason, I imagine that the exhaust length has something to do with the scavenging effect, therefore the amount of vacuum that it pulls in the upper rpm. Set at idle, forget the rest.
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Old 07-10-2010, 02:54 PM
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I also used ATF, a 2x4, and about 15 or so feet of vinyl tubing.
I had the two sides within 1/4 inch at idle.
It definitely made an improvement over the previous setting.
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