Carb conversion

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  • BluegrassDirtbag
    Junior Member
    • Jul 2019
    • 1

    Carb conversion

    So what is the process to go from FI to carb? 08 vulcan bobber.
  • Tattooo
    Senior Member
    • Sep 2012
    • 12407

    #2
    Originally posted by BluegrassDirtbag
    So what is the process to go from FI to carb? 08 vulcan bobber.
    Have you done any searching??

    Comment

    • 1369ftw
      • Apr 2024

      #3
      you will need custom cables. easy to fab with a Dremel cutoff wheel. the lead ends are easily shaped. I use bike brake bolts to tie cables together. if you have a return cable then you remove it from the throttle. do this once and you are an expert. kmart sells a bike tune up kit with all the cables you'll need for 10$

      you will need a choke. get a carb that has a pull up type and you won't need to fab up a choke lever.


      manifold will determine how many carbs you are going to run. if you have a 2 into one manifold I would use the cheap Chinese 42mm Harley Davidson type on ebay. if its good enough for 1,200 cc's will be fine for your Vulcan turd. if 2 manifolds then Chinese pwk 30-34 mm will be fine. again get the type with the pop up choke so you won't need to fab a choke. jetting is easy because these new tech carbs have jetting adjusted from the mixture screw.

      I've even done this to a car. made a gasket out of cork and mounted a carb onto an air cleaner on a foreign car. carb is cheap and simple.

      sorry about my post count, this site keeps kicking it back to 1

      went to indian larry harley davidson custom show. info is on their website I have a cb360 chopped and restomodded. was a strange experience. this was a serious biker event, all the local gangs attended. this was the type of event where they used to put a bike like mine in a bond fire. they ate up my turd like it was
      Last edited by Guest; 07-31-2019, 8:04 AM.

      Comment

      • Skjoll
        Senior Member
        • Oct 2018
        • 259

        #4
        Originally posted by 1369ftw
        ...jetting is easy because these new tech carbs have jetting adjusted from the mixture screw.
        I'll have to strongly disagree. The mixture screw is an idle mixture screw (pilot fuel screw) and only regulates fuel from closed to about 1/4 throttle at best and regulates such a small amount of fuel that by mid range it's essentially no longer a factor.


        There's more to properly dialing in a carb for a particular motor than merely turning a screw. If you want to make tuning easier then your best choice is a Lectron type of carb.
        Last edited by Skjoll; 08-01-2019, 11:31 AM.

        Comment

        • farmall
          Senior Member
          • Apr 2013
          • 9983

          #5
          Skjoll is of course correct. Just slapping on a carb may or may not work. WHY do you think you want a carb? What displacement is your engine?

          If the bike runs well as is it would probably be wise to play with cosmetics instead of fucking around (and spending money) with a carb conversion. Google shows plenty of hits, but not plenty of successful conversions which is understandable.

          Best way to convert to carb is sell the motorcycle and buy a carbed bike, preferably a Harley because they use single carbs. Modding a working EFI bike is highly likely to produce shitty results, and carbs are generally inferior to properly maintained EFI.

          Comment

          • 1369ftw
            • Apr 2024

            #6
            Originally posted by Skjoll
            I'll have to strongly disagree. The mixture screw is an idle mixture screw (pilot fuel screw) and only regulates fuel from closed to about 1/4 throttle at best and regulates such a small amount of fuel that by mid range it's essentially no longer a factor.


            There's more to properly dialing in a carb for a particular motor than merely turning a screw. If you want to make tuning easier then your best choice is a Lectron type of carb.
            first off you want to make your life easier not harder. cv carb like skjoll's pic should be avoided. there have been improvements in Chinese carbs that these mods are unaware of. times are changing and there are now carbs with mixture screws that meter gas and have no air screw. its true. I only know about it because of my time 2stroking. the pz I used and the Chinese pwk series that comes in the size you need (I looked it up) 32-34mm have no air screws. cheap simple and will work on your bike. jetting should not be much of an issue on a 4 stroke bike. jets are cheap.


            farmall did not search ebay to see the prices of carbs. we are talking about 60$ for new bootleg pwk carbs and manifolds 10$ in cable and some bike brake parts. the pz30 is the carb from the lifan 200. so it makes sense that 2 will be fine on a 360. the bootleg Harley Chinese 42mm is $40. I've done the conversion and am happy I did. so happy I changed out complicated klhein with diapragms to modern pz's. It's brand new I can leave the petcock open all night and its not flooded in the morning. they cost like 13$ each shipping included. second season riding on them on that bike.


            why does my post count stay at 1.

            Comment

            • Wiseman
              Junior Member
              • Aug 2019
              • 14

              #7
              My carb isn't for the casual wrench. I run a three barrel downdraft Weber carb from a 2.1 litre Porsche. I'll try yo post a pic to show it.

              Comment

              • Wiseman
                Junior Member
                • Aug 2019
                • 14

                #8
                Fat finger spelling, sorry. I'm new here, am also in Shovelhead US, and Motocantina. You can see more of my bike there. I'll try for a couple more pics here.


                upload pictures online



                My 4 5/8" stroker wheels have had a little over 6 pounds shaved from them, making them about 9 1/2 pounds lighter than stock. Needless to say, it spools up pretty quickly. It's actually pretty reliable. I've had it since 1992, and still change a few things now and then.

                Comment

                • Skjoll
                  Senior Member
                  • Oct 2018
                  • 259

                  #9
                  Originally posted by 1369ftw
                  first off you want to make your life easier not harder. cv carb like skjoll's pic should be avoided. there have been improvements in Chinese carbs that these mods are unaware of. times are changing and there are now carbs with mixture screws that meter gas and have no air screw. its true...
                  That diagram applies to round slide and flat slide carbs as well. The only alternative that I'm aware of that uses a special fuel metering system unlike other carbs, in this case based on intake manifold vacuum and air velocity at the mouths, are Lectron carbs but those are make/model specific and aren't interchangeable. There was also an aftermarket metering system known as 'ThunderJets', IIRC, that you attach to the mouth of a motorcycle carb and uses the same principle as the Lectrons to automatically fatten lean spots but IMO they didn't work all that well.

                  It would be nice if you posted links to these 'improved' Chinese carbs you speak of. The ones I've seen on eBay are just questionable Mikuni VM, Mikuni TM and Keihin PWK knockoffs.

                  Comment

                  • Tattooo
                    Senior Member
                    • Sep 2012
                    • 12407

                    #10
                    Originally posted by 1369ftw
                    why does my post count stay at 1.
                    I don't know it looks like a 2 to me.............

                    Comment

                    • Skjoll
                      Senior Member
                      • Oct 2018
                      • 259

                      #11
                      Originally posted by 1369ftw
                      ... there have been improvements in Chinese carbs that these mods are unaware of. times are changing and there are now carbs with mixture screws that meter gas and have no air screw...
                      BTW, that's pretty much the fundamental difference between carbs that were used on 2-strokes and those used on 4-strokes. The mixture screw on a 2-stroke was an air-bleed screw and is located at the mouth end of the carb... 4-stroke carb mixture screws are located on the manifold side of the carb and meter fuel delivery, they are nothing new and have been in use for as long as I've been alive.

                      Comment

                      • Tattooo
                        Senior Member
                        • Sep 2012
                        • 12407

                        #12
                        Originally posted by Skjoll
                        BTW, they are nothing new and have been in use for as long as I've been alive.
                        Yep nothing new they have been around since the beginning of time as Trump would say.........

                        Comment

                        • 1369ftw
                          • Apr 2024

                          #13
                          the op will be fine with 32-34 Chinese pwk's that should fit easily to the Vulcan intake manifold. if you want stupid simple which is why I think you want to get rid of fi then go with a 42mm pwk. only one idle screw and one mixture. like this you will get that stupid that slow steady idle you are looking for. if the mixture screw is more than 1.5 turns out then go up on the pilot.

                          that Porsche carb is the shit. that was the foreign car I did my fi to carby swap. it was a 914 with a dodge dart carb bolted to the air cleaner with a cork gasket made from a box that cardinal Mendoza brandy came in. worked well and got laid a lot in that car.


                          why are my posts being deleted. what is the point of posting on this site if you are going to kick me to the curb?
                          Last edited by Guest; 08-02-2019, 8:17 PM.

                          Comment

                          • 1369ftw
                            • Apr 2024

                            #14
                            Originally posted by Tattooo
                            I don't know it looks like a 2 to me.............

                            bullshit, look how many posts just on this one thread. what about all the others. why do my images get deleted if the mod doing this does not want to tell me in public then pm me. the battery eliminator thread got deleted three times. why is it so hard to post on this site? what's the problem with this site.

                            where I live every day I have to adjust the idle screws every 3rd day a weather front passes changing barometric pressure. pissed me off I couldn't reach the left carb so I used an adjuster from a ninja I had lying around. pz30's $26 for both is a joke.

                            Last edited by Guest; 08-03-2019, 5:17 PM.

                            Comment

                            • farmall
                              Senior Member
                              • Apr 2013
                              • 9983

                              #15
                              Must be some board software fart deleting images. The admins don't write the board software and have no more control than offered by its defaults. (That's also why giving different boards more descriptive names can't happen and admins have to move questions from the How To section instead.)

                              You could message Lisa Ballard and perhaps register another nick to test. If that one works, keep it and delete the original.

                              Comment

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