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Carb Confusion

Old 03-17-2012, 01:33 PM
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Carb Confusion

My 97 Euro model SH has the stock air filter, Scorpoin high pipes with baffles. I have shimmed the needles .030+.040, 48 pilot, and plugged one front slide hole
and blocked off PAIRS as recommended by 8541Hawk. It runs OK but too rich and gas mileage is 25% less. The problem may be that it has different model carbs than US models:VTPOB instead of VTP1A(Cal.)VPT2A(49state) and different needles:front A1UD,rear A1UC instead of A1UF,A1UE. My bike came with 45 pilots were were changed to 48s in 98 but the carb model changed also.
I had the idea to remove the shims, leave the 48 pilots in and the plugged slide hole. If anyone has any ideas, or has experience with this carb confusion I would appreciate your input. Thanks
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Old 03-17-2012, 01:38 PM
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Whats your main jet sizes?
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Old 03-17-2012, 02:22 PM
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carb confusion

the mains are stock : 175+178
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Old 03-17-2012, 09:09 PM
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Float Valves

Originally Posted by MarkN View Post
My 97 Euro model SH has the stock air filter, Scorpoin high pipes with baffles. I have shimmed the needles .030+.040, 48 pilot, and plugged one front slide hole
and blocked off PAIRS as recommended by 8541Hawk. It runs OK but too rich and gas mileage is 25% less. The problem may be that it has different model carbs than US models:VTPOB instead of VTP1A(Cal.)VPT2A(49state) and different needles:front A1UD,rear A1UC instead of A1UF,A1UE. My bike came with 45 pilots were were changed to 48s in 98 but the carb model changed also.
I had the idea to remove the shims, leave the 48 pilots in and the plugged slide hole. If anyone has any ideas, or has experience with this carb confusion I would appreciate your input. Thanks
Float valves may be leaking. Mine were and the proof is when after setting for a day pulled the fuel lines off from the petcock no fuel ran out of them. Over the course of a day all the fuel in them ran past the valves and down into the intakes and that's not good.
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Old 03-18-2012, 12:29 PM
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carb cnfusion

about the pilot screw settings: a Honda mechanic in my town led me to believe that the pilot screws are air screws and that turning them out is leaning the mix
so I set them at the Honda spec of 2 3/4 turns out. I started at 2 1/4 front and 2 1/2 rear and it runs a little better I think, although I am still hoping one of you SH experts will help me get on the right track. I checked the float valves and they are OK.

Last edited by MarkN; 03-18-2012 at 12:31 PM. Reason: forgot something
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Old 03-30-2012, 01:43 PM
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end of the thread

To answer my own question: I took the carbs off for the third time and removed the .030 + .040 needle shims, I left the 48 pilot jets in and the plugged front slide hole. The bike runs really well and now I can get on with the suspension work. I found an öhlins shock and I got a Racetech full kit for the front. Thanks for your input guys. Mark
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Old 04-17-2012, 04:06 PM
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Originally Posted by MarkN View Post
about the pilot screw settings: a Honda mechanic in my town led me to believe that the pilot screws are air screws and that turning them out is leaning the mix
so I set them at the Honda spec of 2 3/4 turns out. I started at 2 1/4 front and 2 1/2 rear and it runs a little better I think, although I am still hoping one of you SH experts will help me get on the right track. I checked the float valves and they are OK.
A good way to remember if they are air or fuel screws is if they are on the air filter side of the slide they are air screws and if they are on the engine side of the slide they are fuel screws.

Generally air screws are on two stroke dirt bikes, and most 4 stroke bikes including ever streetbike I can remember have fuel screws.

It sounds like you got your issue fixed but everything you did would richen up the mixtures, so just back it off a bit and you should be good as it sounds like you've done.
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