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  1. #1

    Default VStar 650 S&S Carb/fuel pump question

    Hi Guys,

    I am starting a few projects on my wifes bike, its a 2014 Vstar 650. The first thing to go will be the twin carbs.

    I was looking at an S&S Carb option for simplicity and the fact that there are some great bolt on air cleaner options.

    But the one piece of info I have not been able to find is if the guys that have made the mod keep the fuel pump feeding the carb or not?

    Has any of you builders/tinkers got some thoughts on the best way forward.

    Thanks heaps, John.

  2. #2
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    The S&S needs only gravity feed pressure.
    I guess the pump is only necessary when the float level is above the petcock level. So where is your fuel tank?

  3. #3

    Default

    Quote Originally Posted by Sky View Post
    The S&S needs only gravity feed pressure.
    I guess the pump is only necessary when the float level is above the petcock level. So where is your fuel tank?
    thanks Sky,

    I will be running the standard tank. Standard they would be pretty level, but with the Super E, the carb would be below the fuel tap.

    I was hoping the leave the fuel pump in place as I really don't know if the tank cap if pressurized or not. But if it's not needed that does make the whole setup that little bit less complicated.

    The other concern I had was that the fuel pump pressure might be two great for the Super E float and needle.

    thanks again, John.

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    Yup, just make sure the tank is vented somehow and ditch that pump.
    If you really want to keep it make sure the regulator keeps it around like, three psi. Maybe up to five psi? That's roughly equivalent to atmospheric/gravity fuel pressures.

  5. #5

    Default

    Thanks Sky,

    I guess that is the magic number, 3 to 5 psi. it would also take out the need to run a modified fuel cap.

    Thanks again, I really appreciate your help.

    John.

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    Pretty sure the caps are vented though mate

  7. #7

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    Cheers Guys,

    I have been battling a flat off idle low rev high load condition that wasn't there when we bought the bike. But once we added the new pipes it was.

    Working the jets on the twin carbs is not fun at all. So a single is what I thought I would do, plus the filter options are endless for the S&S.

    Up side, if the S&S is no good on the 650, I can always use it on my 1100.

    John.

  8. #8
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    A Super is a bit large for such a small displacement but a single Harley CV carb may work decently and give more low and midrange. It's easy to sell an S&S to fund other carbs too.

  9. #9

    Default

    Quote Originally Posted by farmall View Post
    A Super is a bit large for such a small displacement but a single Harley CV carb may work decently and give more low and midrange. It's easy to sell an S&S to fund other carbs too.
    Hi Farmall,

    I have to agree on the S&S, that is the main reason I haven't purchased one yet. they are about the same price in Aus as they are in the U.S with delivery.

    My gut feel is that the 40mm is more on the mark for size. The goal is to give my wife a crisp bottom end, the s&s at 47mm will do the complete opposite.

    thanks for you thoughts and advised, it is all greatly appreciated.

    john.

  10. #10

    Default

    Hi guys,

    I decided to make my own intake manifold to get the look I was after.

    Went the 33mm TM flat slide Mikuni. Dropped the TPS for a MAP sensor. The map sensor used was a WRX OEM unit, the wiring and plug are the same. The out put signal appears to be the same. Works great.

    Extended the internal throttle cables so the routing of the cables was factory.

    I know, not pure Chop Cult, I like to make changes that look factory but at a closer look makes you look twice.

    John.

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    If your up for making another id be willing to pay mate. Im not allowed to work on my bike at my workplace anymore haha.

  12. #12
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    I know, not pure Chop Cult, I like to make changes that look factory but at a closer look makes you look twice.
    That's even better than crude chobbery and you did a tidy job. How well does it run?

    The goal is to give my wife a crisp bottom end.
    Make sure you NEVER criticize their current bottom end! Women never forget the slightest mention of the most trivial imperfections and they will make sure YOU never forget they never forgot!

  13. #13

    Default

    That's funny Farmall. how does it run, wow would be the word to best describe the difference.

    Very strong off idle and rolls on through to 100MPH. I haven't even got the open pipes back on yet.

    The next task is the air cleaner, the Arlen Ness unit turned up yesterday. I will need to make a new backing plate to get the air cleaner as tight as possible to the engine. My wife is only 5ftand short legs have troubles reaching the back brake and going around the air cleaner. I may even look at making a foam filter element that is only I inch deep to really cut down the width.

    21guns, that intake took over 30 hours to make, I would like to redo it in the future in stainless steel. if I do, I will make two. The first one was trial and error but bade it work in the end, hence making it out of mild steel. it was easy to cut and shut to get it right. hours on the grinder and file to smooth it out.

    john.

  14. #14
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    Default

    Quote Originally Posted by outaoffice View Post
    Hi guys,

    I decided to make my own intake manifold to get the look I was after.

    Went the 33mm TM flat slide Mikuni. Dropped the TPS for a MAP sensor. The map sensor used was a WRX OEM unit, the wiring and plug are the same. The out put signal appears to be the same. Works great.

    Extended the internal throttle cables so the routing of the cables was factory.

    I know, not pure Chop Cult, I like to make changes that look factory but at a closer look makes you look twice.

    John.
    Hey, i made a single carb manifold as well but went with the cv40 carb. Exactly what map sensor did you use and how did you hook it up? I dont have an extra tps to use so i was going to go with a voes. Maybe this would work better.

    Thanks

  15. #15

    Default

    Quote Originally Posted by Luke2 View Post
    Hey, i made a single carb manifold as well but went with the cv40 carb. Exactly what map sensor did you use and how did you hook it up? I dont have an extra tps to use so i was going to go with a voes. Maybe this would work better.

    Thanks
    hi, Sorry about the delay.

    Work and working on the bike has been hectic.

    Finally finished the air cleaner today, major effort and gained as much room as possible. my wife is only 5ft tall, getting a leg around the air cleaner and using the back brake was proving to be a stretch.

    All fixed now.

    Ok, MAP sensor, that was off a WRX 2009 model 3 bar standard sensor. the fitting is the same as the VStar TPS connector and the pin out the same. Could not have been easier if I tried, it plugs straight in. Adding a baffle can would be better to reduce the heart beat of the v-twin in the vacuum line. But for now the bike feels great so it can stay.

    John.

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  16. #16
    JetBlackII
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    Default

    Nice slim filter body; the bulked out, in the way shit sucks.

  17. #17
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    Quote Originally Posted by outaoffice View Post
    hi, Sorry about the delay.

    Work and working on the bike has been hectic.

    Finally finished the air cleaner today, major effort and gained as much room as possible. my wife is only 5ft tall, getting a leg around the air cleaner and using the back brake was proving to be a stretch.

    All fixed now.

    Ok, MAP sensor, that was off a WRX 2009 model 3 bar standard sensor. the fitting is the same as the VStar TPS connector and the pin out the same. Could not have been easier if I tried, it plugs straight in. Adding a baffle can would be better to reduce the heart beat of the v-twin in the vacuum line. But for now the bike feels great so it can stay.

    John.

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    Thanks man. Air cleaner looks great. What filter did you use in there? its really slim which is awesome.

  18. #18

    Default

    Quote Originally Posted by Luke2 View Post
    Thanks man. Air cleaner looks great. What filter did you use in there? its really slim which is awesome.
    hi Luke,

    The filter is straight Filter Foam from a shop called Clark Rubber in Australia. Its 25mm thick which was perfect, then I simply use filter oil.

    the filter was easy to cut with a box knife.

    So far so good.

    John.

  19. #19

    Default

    At the risk of reviving an old Post... I'm trying to do this same conversion and was interested in the map sensor plumbing, where/how did you hook it up? Bike is sick dude!
    Ok, MAP sensor, that was off a WRX 2009 model 3 bar standard sensor. the fitting is the same as the VStar TPS connector and the pin out the same. Could not have been easier if I tried, it plugs straight in. Adding a baffle can would be better to reduce the heart beat of the v-twin in the vacuum line. But for now the bike feels great so it can stay.

  20. #20

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    Default

    I know, old thread but since it's been resurrected I thought I'd throw in my 2 about the carbs. I initially was going the 'one carb' route for simplicity's sake but keeping the dual carb unit was hella easier. I removed the entire intake, put a couple of pods on the carb mouths, rejetted and synched the carbs and that was it... haven't touched them in several thousands of miles of trouble-free riding. When going to a single carb you'll still have to rejet it to work and doing two siamesed carbs doesn't cost much more time at all compared to fabricating shit for the single carb to work.

    Something else worth considering... when it comes to carbs people tend to go too large for a street bike. IMO you might want to go one or two sizes larger when resorting to a single carb but if it's too big your low to mid range performance will suffer because intake velocity will be slower so the atomized fuel won't be as fine and runs the risk of dropping out onto the intake walls. This problem is compounded on an oversquare motor like the XVS650's that people don't usually keep up in it's optimal part of the power band... after all the XVS650 motor has more in common with a Suzuki SV650 or Cagiva Alazzurra than a HD which a lot of owners tend to ride it like.

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