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Author Topic: What RPM where cab sync irrelevant  (Read 978 times)
kodiakfisher
Member
*****
Posts: 97


Beaverton, OR


« on: December 04, 2016, 05:11:36 PM »

Here is my curiosity...

Just used the digi sync to sync the carbs. 197-198 all around. I have always had tiny bit of roughness at 2000rpm. I got a little bit better but still there. Nothing seems to have an impact. I would believe that a vacumn leak would show up on the digi sync but none of them where off more than 3 197 on #3 and 200 on number one cylinder. The roughness manifests itself by trying to hold RPM's at 2k and it flutters around a bit but at 3k perfectly smooth.

New plugs (gapped exactly the same and torgue with torque wrench) - check
New Air filter - check
New oil - check
Previously have run a can of Sea Foam
Stabil in tank over the winter

My battery has been giving me a bit of trouble now sits on trickle charge and have a new one that will go in the bike early spring.

I am thinking that at about 2k rpm I am transitioning off one carb circuit hence a tiny bit of roughness. 

Ready Set Go!

Doug E on the Valky
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gordonv
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Posts: 5762


VRCC # 31419

Richmond BC


« Reply #1 on: December 04, 2016, 05:18:39 PM »

Here is my curiosity...

The roughness manifests itself by trying to hold RPM's at 2k and it flutters around a bit but at 3k perfectly smooth.

Previously have run a can of Sea Foam

Now try a 1/2 can of Berryman B12 in a 1/2 tank off fresh/clean fresh fuel. Take it out for a ride, high gear, low speed, so you run the engine in a lower RPM. 1.5-2K approx. Around the city on flat ground. This way you go through all the rpm range. Let sit over night, and repeat.

If it improves, repeat the carb cleaner. If it doesn't clear up fully, but is better. Do the same, but with Techron this time. Then just go out and enjoy. Use Chevron with Techron for gassing up. It should get better and better.

If not. Research carb rebuild/cleaning.

I feel you ports a plugged, and the heavy doses of carb cleaner should do something. Seafoam will work for some, but not all, of the cleaning.
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1999 Black with custom paint IS

Ricky-D
Member
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Posts: 5031


South Carolina midlands


« Reply #2 on: December 05, 2016, 06:43:44 AM »

If you index your throttle you would definitely know exactly where you are in the opening range of the throttle. I would say if you are simply sitting in neutral holding the throttle best you can at 2000rpms, you are still in the low speed (idle) circuit. Rpms cannot be the determining factor in throttle setting.

***
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2000_Valkyrie_Interstate
Pete
Member
*****
Posts: 2673


Frasier in Southeast Tennessee


« Reply #3 on: December 05, 2016, 06:58:19 AM »

If you sync at idle then each carb is pulling the same vacuum at idle. That is all that sync does, ensuring that each carb starts from the same vacuum.

If you have questions about other RPMs sync then leave the gauges connected and raise the rpm using the idle adjustment. I would not use the throttle as your hand may or may not be as steady as the idle adjustment screw.

I would expect to see some variation, although it has been many years since I have done this I do not remember how much variation.

If you experience a very large variation at some level, that would indicate a problem.

If the issue is below 3000 rpm I would attempt to adjust the pilot screw of the carb in question to see if it has any effect.
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Gavin_Sons
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Posts: 7109


VRCC# 32796

columbus indiana


« Reply #4 on: December 07, 2016, 05:03:48 AM »

Read this, might answer some questions. Straight from the man himself.
http://www.valkyrieforum.com/bbs/index.php/topic,78142.0.html
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Houdini
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Posts: 1975


VRCC #28458 - VRCCDS#144

Allen, TX


« Reply #5 on: December 07, 2016, 06:12:18 AM »

I went through this same scenario once when my IS sat for about 1.5 years.  To fix mine I poured a whole can of Berrymans into an almost empty tank, rode her over to the gas station and filled her up, wrapped a bungy cord around the open throttle to hold it at the spot that she was stumbling and let her sit there for about half an hour.  Remember she needs air flow so set a fan to blow across the radiator and headers to keep her comfortable.

This procedure cured about 90% of the stumble, they rest was gone after a few days of riding her around.  That was a couple of years ago and she is still running fine, no carb rebuild necessary.

In my experience Seafoam will do exactly nothing to improve an issue like this, Berrymans will.
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"A Camera And A Bike....What More Do I Need?

kodiakfisher
Member
*****
Posts: 97


Beaverton, OR


« Reply #6 on: December 07, 2016, 11:39:20 AM »

Read this, might answer some questions. Straight from the man himself.
http://www.valkyrieforum.com/bbs/index.php/topic,78142.0.html



Wow great article thanks it was enlightening for sure. I suspect if I am getting 32mpg running 80mph across the flat lands of North Dakota I'm probably good.

Doug E on the Valky
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