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  • High Speed Needle?

    Well, yesterday I brought my 45 back to life after it sat for over 12 years. All I did to it was clean up the M88 carb and install a new float. I set the low speed needle per the service manual and the engine idles smooth and true. I can twist the wick and get a pretty good responce. After it got through puking the oil that had sumped into the bottom end I took it out on the road to play with the high speed needle.

    The service manual doesn't mention how to adjust the high speed needle. As I rode down the road I played with the high speed needle and it doesn't seem to make any differance in performance reguardless of where that needle is set. How do you guys adjust it..? I should mention that while riding I can twist the throttle and it doesn't bog down,spit or miss a beat. I get a slow and steady increase in speed.

    Having never ridden a 45 before so I don't have a good referance as to what type of performance I should be getting when I crack her open. It definitely does not plant my butt into the seat the way my panhead does. Everyone said not to expect much power from these 45's but I have to think that there must be more than I'm getting. So how do I set that high speed needle..? -Steve

  • #2
    Should be fixed jet for high speed in the M88. Gently seat the needle and look at points settings and valve lash to see if something there is making your machine feel slow. A stock WL has a lot less power than your pan.

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    • #3
      When converting an M88 to an adjustable HS needle, please be aware that occasionally the needle must be lengthened to fully reach its seat.

      The M88 was designed to be metered by the fixed jet alone, so unless you have a moderate overbore or other modifications, it may be best to remove the fixed jet and install a common gallery plug, so that the adjustable needle does all of the metering instead of just adding additional fuel.

      You will need to be going over 30 MPH to be using the HS circuit, and allow lag time between trial adjustments for the system to come to equilibrium.

      As the lowspeed circuit reverses itself, it also affects HS tuning. Therefore you may have to re-adjust both needles a time or two before a sweet relationship between the two circuits is achieved.

      ....Cotten

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      • #4
        Koane,
        I do need to replace the points and look into the valve adjustment but I just didn't want to mess with to many things before I got it running first. That way if I had trouble starting it, I would be working with a short list of things that could be wrong. Now that it is running I will look at other adjustments.

        Cotten thanks for jumping in here. Please forgive me but I'm a little confused here. Is the knob marked "power" the high speed needle or something else..? I will need to re-read your reply a few times cause most of it went right over my head. I'm not the sharpest knife in the drawer but I do have the ability to learn.

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        • #5
          Steve!

          Your M88 came with a cap over the HS needle (on the Power) side.

          If you have a knob, you are converting it to an adjustable needle.

          ...Cotten

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          • #6
            Cotten, It came to me with the knob. Are you saying to just screw it in to the bottom and forget about it..?

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            • #7
              Steve!

              As I posted earlier, inspect to make certain that it can bottom out (point to seat, not just the knob itself), or it will not adjust anything.

              And if you motor is just a mild overhaul, then remove the jet and plug it.

              Start out at about a turn and a half, and tune from there.

              Good luck!

              ...Cotten
              PS: if you cannot seem to over-enrichen the HS circuit, then a vacuum leak might be present.

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              • #8
                OK.... I think I finally understand what your telling me now. I will check the lenght of it tonight. Do I have you shacking your head at me yet Cotten..?

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                • #9
                  Steve!

                  Shacking one's head sounds painfull....

                  Another note on slow accelleration complaints on vintage machines:
                  It is not uncommon to have the clutch slipping imperceptably if the footpedal has it's tensioner dragging.

                  Modern riders should loosen them completely to allow the pedal to pull itself fully into gear automatically, unless competing in an enduro or crossing treacherous terrain, as they were designed for.

                  Relying upon the pedal tensioner to keep the machine out of gear at a stop is the real origin of the term "suicide clutch".

                  ....Cotten

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                  • #10
                    Well I got to go on a much longer ride today. Took it out on a road where I could maintain about 45mph and found that the HS knob does do something. If I twist it outward at that speed I can get the engine to just about flood itself out. If I twist it in I get just the oppisite. There are a lot of turns of the knob in between it flooding out and starving. Can't give an exact number of turns cause I still need to keep an eye on the road. In between those two settings the engine runs strong but there is a little lag when I give it a quick twist of the wick.

                    I'm hoping that its on the rich side. I'm going to take a look at those points and valve adjustments this week end then do it all over again. I'll keep watching what the plugs look like to make sure it's not running to lean. Thanks again guys for listening to me babble on. I'll keep you all posted as to my progress.-Steve

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