Announcement

Collapse
No announcement yet.

Teething Issues - RS250

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • Teething Issues - RS250

    Taking the time to get the RS250 ready for road going duties. Part of that is going through some heat cycles in the garage with the fairings off, checking the gauges and checking for leaks.

    There are a few small issues that I'm fixing myself - too much slack in the kick start, a few small weeps/leaks. But there's an issue I'd like some advice on please.

    At idle, the Exhaust Gas Temperature sensor reads a pretty steady ~160C for both barrels. Blip the throttle though (1/4 turn) and the temperature on the upper cylinder decreases, while the lower cylinder increases. Repetitive blipping has the lower cylinder get to about ~210C while the upper dives below 100C and starts reading "Cold" on the EGT. Let it idle again and it returns to ~160C for both.

    It's not a sender issue, there's constant luke-warm smoke coming out of the pipe whereas the other is hot. There's also a spittle of fuel coming out of the lower pipe (upper cylinder). Inspection of the manifolds show the lower pipe is getting some blow-by too, but nothing on the upper.

    Both carb slides have been synchronised by Derek Ball. The Flow Commanders affect both carbs equally. Main jets were checked and double-checked before assembly. I haven't checked ignition, but as it's working at idle I'd assume (for the moment) that it's fine.

    Could it be a solenoid issue? Any suggestions would be welcome. [MENTION=6812]rgvlee[/MENTION]; [MENTION=17757]Gangus[/MENTION]; [MENTION=21752]EEKNOWS[/MENTION]
    Click Link for My Bikes:

    Aprilia RS250
    1985 GSXR750 "Slabbie"

  • #2
    Longshot but could the airflow in the pipes be flowing differently and therefore interact with the sensors differently.
    In sterquiliniis invenitur.

    Comment


    • #3
      Have you checked the pilot air solenoid is working/connected correctly on the LH carby? Both carbs share 1 pilot solenoid.

      Comment


      • #4
        Warm it up on a rear race stand, so the bike is level.
        Seems to make a difference.
        Just something to try.
        Also check your needles are on the same clip, as a long shot

        Comment


        • #5
          Originally posted by Crobbo View Post
          Longshot but could the airflow in the pipes be flowing differently and therefore interact with the sensors differently.
          I really, really hope not I'm confident that the sensor is giving me accurate information, it's supported by the exhaust temperature I can feel with my hand near the muffler exit.

          Originally posted by EEKNOWS View Post
          Have you checked the pilot air solenoid is working/connected correctly on the LH carby? Both carbs share 1 pilot solenoid.
          I haven't. If they both share the same pilot air solenoid though, how could it work for one cylinder and not the other?

          Originally posted by Gangus View Post
          Warm it up on a rear race stand, so the bike is level.
          Seems to make a difference.
          Just something to try.
          Also check your needles are on the same clip, as a long shot
          Alrighty, I will. Geez it'd be nice if the problem is just because the bike isn't level! I'll check the needles too.

          Girlfriend has the day off tomorrow so it might have to wait until Thursday...
          Click Link for My Bikes:

          Aprilia RS250
          1985 GSXR750 "Slabbie"

          Comment


          • #6
            Could be connected to the main air correction circuit

            Comment


            • #7
              is one carb's float level too high? have you recycled the old ignition leads and coils and if so are they the same (serviceable) resistance?
              Originally posted by Bendito
              If we get to a stop and we are missing a dozen bikes and you are last, it was your fault. Don't be that guy. No one likes that guy.

              Comment


              • #8
                Originally posted by g0zer View Post
                is one carb's float level too high? have you recycled the old ignition leads and coils and if so are they the same (serviceable) resistance?
                I'll go through the carbs again tomorrow, checking floats, needles and jets. I'll be surprised if there are any issues though, I double and triple checked them when I put them in, but it's worth checking again. Maybe something from the tank has blocked a jet even, although I'd have thought the filter would catch it.

                The coils and leads are brand new Zeeltronic items so I'd be surprised if they're the issue, but I'll check them at the same time.

                What I'm not so sure of is how to check the solenoids. What's the best way?
                Click Link for My Bikes:

                Aprilia RS250
                1985 GSXR750 "Slabbie"

                Comment


                • #9
                  http://www.thetuningworks.co.uk/stor...oducts_id=1360

                  any luck yet?

                  Comment


                  • #10
                    Originally posted by Gangus View Post
                    Ouch, that's more expensive than the tuning unit I have! But it may come to that.

                    No luck yet. I've got a photo shoot on Sunday so I had to abandon major works in order to have it in one piece.

                    Early next week is looking like it won't hurt to be outdoors too
                    Click Link for My Bikes:

                    Aprilia RS250
                    1985 GSXR750 "Slabbie"

                    Comment


                    • #11
                      Didn't get the sensors mixed up? ie swap them.

                      Comment


                      • #12
                        Negative, unfortunately. EGT probes have a connector that prevents it from being attached incorrectly to the gauge so at least one of the cylinders is running cold at RPM. Smoke and exhaust temperature from the corresponding pipe tells me that the sensor is correct and doing it's job.

                        I'm sure it won't be a big deal to fix, it's just finding the culprit among the hundred parts that Suzuki/Aprilia used for the fueling
                        Click Link for My Bikes:

                        Aprilia RS250
                        1985 GSXR750 "Slabbie"

                        Comment


                        • #13
                          Wont be the Suzuki part

                          good luck.

                          Comment


                          • #14
                            I have a gensig which is basically the same as above if needed

                            Comment


                            • #15
                              The thing that has me thinking is that both the idle circuits are fine, egt even at idle. This also tells me you don't have a spark issue/ fouled plug. I said check the needles as this the start of the main circuit. Pay particular attention to the main air circuit. I would want to see carb cleaner flow through this passage. The suggestion of the solenoids is that they have an effect on this circuit. To eliminate an incorrect setting within the zeel unit run the Std sapc to rule this out.
                              I'm pretty sure to check solenoid function you can blow air up the black line with your mouth and apply 12v to either open or close. Haven't done this myself as never chased an issue in this area.
                              Good luck with the photo shoot tomorrow!

                              Comment

                              Working...
                              X