Modifications - Performance Discuss aftermarket and DIY performance modifications

Carb Confusion

Thread Tools
 
Search this Thread
 
Old 03-17-2012 | 02:33 PM
  #1  
MarkN's Avatar
Thread Starter
Junior Member
Squid
 
Joined: Mar 2011
Posts: 9
MarkN is on a distinguished road
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
Old 03-17-2012 | 02:38 PM
  #2  
jay956's Avatar
Senior Member
SuperSport
 
Joined: Aug 2009
Posts: 684
From: Richmond, VA
jay956 is on a distinguished road
Whats your main jet sizes?
Old 03-17-2012 | 03:22 PM
  #3  
MarkN's Avatar
Thread Starter
Junior Member
Squid
 
Joined: Mar 2011
Posts: 9
MarkN is on a distinguished road
carb confusion

the mains are stock : 175+178
Old 03-17-2012 | 10:09 PM
  #4  
zxbud's Avatar
Senior Member
Superstock
 
Joined: Oct 2011
Posts: 273
From: Pompano Beach, Fl.
zxbud is on a distinguished road
Float Valves

Originally Posted by MarkN
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.
Old 03-18-2012 | 01:29 PM
  #5  
MarkN's Avatar
Thread Starter
Junior Member
Squid
 
Joined: Mar 2011
Posts: 9
MarkN is on a distinguished road
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 01:31 PM. Reason: forgot something
Old 03-30-2012 | 02:43 PM
  #6  
MarkN's Avatar
Thread Starter
Junior Member
Squid
 
Joined: Mar 2011
Posts: 9
MarkN is on a distinguished road
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
Old 04-17-2012 | 05:06 PM
  #7  
GTS's Avatar
GTS
Seasoned tech
SuperSport
 
Joined: Apr 2012
Posts: 576
From: Issaquah, WA
GTS is on a distinguished road
Originally Posted by MarkN
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.
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
JoeSnowden
Technical Discussion
0
06-03-2009 03:10 AM
Firestorm996
Technical Discussion
17
03-05-2009 11:54 AM
Tweety
General Discussion
18
10-25-2008 10:52 AM
Pimpsterbim1
General Discussion
4
06-02-2008 10:57 PM
Otto Man
General Discussion
8
03-10-2007 08:40 PM




All times are GMT -7. The time now is 03:43 AM.


Top

© 2024 MH Sub I, LLC dba Internet Brands



When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.