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Old 02-26-2013, 10:03 PM   #31
supershaft
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Why is everyone running such small carbs. They run a lot better with bigger carbs IMO. 900's and 1000's? Choose between 36 and 38mm. Concerned about bottom end power? I know it sounds counter intuitive but 38mm Mikuni's OR dells have way more low end response than 32mm Bings. I have made the swap many times and I usually feel a bigger increase in performance in the lower revs versus higher up. Use larger Mikuni's and compared to Bings have it better on the bottom AND top. When it comes to carbs, you can have your cake AND eat it too!
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Old 02-26-2013, 11:16 PM   #32
Kt-88
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Quote:
Originally Posted by supershaft View Post
Why is everyone running such small carbs. They run a lot better with bigger carbs IMO. 900's and 1000's? Choose between 36 and 38mm. Concerned about bottom end power? I know it sounds counter intuitive but 38mm Mikuni's OR dells have way more low end response than 32mm Bings. I have made the swap many times and I usually feel a bigger increase in performance in the lower revs versus higher up. Use larger Mikuni's and compared to Bings have it better on the bottom AND top. When it comes to carbs, you can have your cake AND eat it too!
Mostly because I already own the 32's. I thought they were 34s and I'm a little saddened, but that's ok.
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Old 02-27-2013, 05:14 AM   #33
hardwaregrrl
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Quote:
Originally Posted by supershaft View Post
Why is everyone running such small carbs.
My main reason was and still is, economy. I wanted a little more punch off the line without suffering reduced mpgs. I have been able to achieve on average 1-2 more mpgs with the 32TMs then the Bings. Noticeable difference on acceleration, I don't need anything more than that right now.
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Old 02-27-2013, 05:52 AM   #34
oldroadie
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Why is everyone running such small carbs?
Simple, I'm just a rider, not a racer. A smooth running bike with good power is all I need.
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Old 02-27-2013, 09:47 PM   #35
oldroadie
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Dude! Focus on the thread. Post the model, exhaust, altitude and mikuni jetting information from your bike and quit telling me how to set up my bike.
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Old 02-27-2013, 10:21 PM   #36
supershaft
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Originally Posted by oldroadie View Post
Dude! Focus on the thread. Post the model, exhaust, altitude and mikuni jetting information from your bike and quit telling me how to set up my bike.
Man dude, I thought I was giving good advise, not telling you what to do and I thought it was in the spirit of this thread since it is a lot more so far that just listing jet sizes. Oh well, I don't care. I'll go back up and erase it.
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Old 03-01-2013, 12:25 AM   #37
Kt-88
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Opened my carbs up today. Here's what's in them at the moment.

Slide is a 3.0
Needle is a 6DH7
Main is a 190
Pilot is a 35
Needle Jet is 159 P-5

Bill from Rocky Point says that will be rich especially at 4400 feet. I dropped the needle to the uppermost setting and screwed in the mix to one turn out. When the cables get here we will see!
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Old 03-01-2013, 05:52 AM   #38
oldroadie
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Quote:
Originally Posted by Kt-88 View Post
Opened my carbs up today. Here's what's in them at the moment.

Slide is a 3.0
Needle is a 6DH7
Main is a 190
Pilot is a 35
Needle Jet is 159 P-5

Bill from Rocky Point says that will be rich especially at 4400 feet. I dropped the needle to the uppermost setting and screwed in the mix to one turn out. When the cables get here we will see!
I'm at 900 ft and that would be too rich for me. I'm At a 180 main with 25 pilots now and it's still a little rich, I'll be trying some 170 mains next.
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Old 03-01-2013, 10:07 AM   #39
Kt-88
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Originally Posted by oldroadie View Post
I'm at 900 ft and that would be too rich for me. I'm At a 180 main with 25 pilots now and it's still a little rich, I'll be trying some 170 mains next.
I wonder how much of a difference 150cc makes? I'm willing to bet not as much as 3000ft. I wonder how much effect dropping the needles will have?
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Old 03-01-2013, 12:45 PM   #40
Uncle Pollo OP
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Quote:
Originally Posted by Kt-88 View Post
Opened my carbs up today. Here's what's in them at the moment.

Slide is a 3.0
Needle is a 6DH7
Main is a 190
Pilot is a 35
Needle Jet is 159 P-5

Bill from Rocky Point says that will be rich especially at 4400 feet. I dropped the needle to the uppermost setting and screwed in the mix to one turn out. When the cables get here we will see!
I am at 5k feet. Sounds waay too rich
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Old 03-01-2013, 12:50 PM   #41
Uncle Pollo OP
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Originally Posted by Kt-88 View Post
I committed. I'll be running vm32s on the r90/6 as soon as they arrive.

I'd like to keep the stock air filter and box setup so that will require some creative engineering. I'll post what size components are in the carbs as well as how it goes when all is assembled. I'm sure I won't get it right at first.
bought coolant hoses for my carbs. One trip to the big auto store and I was set.
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Old 03-01-2013, 05:21 PM   #42
Kt-88
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bought coolant hoses for my carbs. One trip to the big auto store and I was set.
Sweet! Thanks!
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Old 03-02-2013, 07:12 AM   #43
DeutschMark
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Keep an eye on that coolant hose. It might not stand up to ethanol.
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Old 03-02-2013, 03:25 PM   #44
Kt-88
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Got the cables in today. Jets, slides, and needles are as mentioned in previous post.

First I had the needles dropped all the way. This would not allow the bike to rev past the pilot jet range at all. I didn't however play with the mix screw in this position.

I moved the needle down a clip- one above middle- and I could rev, but only smoothly when the mix screw was all the way in.

At full throttle the bike isn't happy but it scoots pretty well in the 1/3 -> 2/3 range.

It's very easy to kill with full throttle off idle. I suppose I have a lifetime of CV carb riding to unlearn.
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Old 03-04-2013, 05:19 AM   #45
oldroadie
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The old rule of thumb is one groove on the needle equals three main jet sizes. And the mix screw on our Mikunis is opposite the Bings as it meters fuel and not air, the air is metered by a separate jet at the mouth of the carb.

Screw all the way in suggests the main is bleeding fuel into the carb even at idle, maybe from the needle height adjustment as well as the large main. You could try backing the idle screw out and just getting the idle circuit tuned. That would at least give you a baseline to start adjusting the mains and needle height. And, of course the variable needle sizes and the slide cut away will affect performance too, but, you can get very close for comfortable riding and then tweak for performance.
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