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    Acceptable Warm Up or Something Else?

    Firstly: Here is my back-from-the-dead 650GL.

    DSC07925.jpg

    Rescued it with a frame so hacked up that a café was the only thing I could do with it. The harness was handed to me in a box and resembled a rats nest. Anyway...the 4:1 was what it came with along with pods on the CV carbs. Apologies to the purists inserted here. The jets had obviously been fettled with in the past because she does run - very well, actually when nice and hot. That being said: she warms for a few minutes on partial choke in the driveway and off I go. The first couple of minutes after that is what I have a question about: she surges and runs rough at low/medium speed/throttle until I wind her up a few times and then runs smooth throughout the RPM range. Is that a normal running condition? Bear in mind that I am riding in the South FL sunshine with temps around 80 degrees. I'd be happy to blame the jetting but thinking logically, why would the running improve once I get the RPMs up there a few times? As I sit here typing, perhaps what I should have done was apply the choke to see if the rough running continued - would that be a worthwhile trial to conduct? Haven't done complete plug chops, but plugs I have read at idle say lean. Again - if I am lean, it doesn't seem to affect running beyond the first few minutes.
    Anyway - thanks in advance. Just seeing if I'm missing anything. Haven't synced the carbs yet and there are small rpm changes when I spray around the carb mounts - so obviously two areas I still need to address.

    Thanks again.

    Geoff

    #2
    DSC07928.jpg

    Another view.

    Comment


      #3
      Pipes and pods and lean jetting. Yep sounds about right. Engine gets hotter there fore so does the jetting, hence it runs better when warm. And i never let a engine "warm up" on the choke. extra fuel washes the bores. I always ride off on light throttle and low revs till its warm.

      Comment


        #4
        So, what jetting does it currently have in it?
        Applying some choke while running is a good test
        But, sync the carbs!!!
        1978 GS 1000 (since new)
        1979 GS 1000 (The Fridge, superbike replica project)
        1978 GS 1000 (parts)
        1981 GS 850 (anyone want a project?)
        1981 GPZ 550 (backroad screamer)
        1970 450 Mk IIID (THUMP!)
        2007 DRz 400S
        1999 ATK 490ES
        1994 DR 350SES

        Comment


          #5
          On one of the main jets through my many carb pulling-and-cleanings, I noted 150 on one of them, but nothing on the others. Maybe its my eyesight, but I couldn't make out anything else.
          Sharpy: does she stumble while she's warming up it you push it?
          Big T: 10-4 on the syncing. I'll order one ASAP. Bench balancing will only get you so far, I guess.

          Thanks for your input.

          Geoff

          Comment


            #6
            I had the same problem until about to weeks ago. I had dipped my carbs and cleaned them twice so I was sure it wasnt dirty carbs .. until it was. FIrst few miles it would buck like a horse. Turned out .. I was stupid and when installing my float needles they were very difficult to get in so I put the finest amount of white lithium on the rubber to get them seated.

            I went to do boots two weeks ago and the little TINY hole to the outside of the butterfly was covered in spudge and the tiny hole just other side of the butterfly that controls that first 1/4 turn of the throttle was the same. I dont know what would make it get better with warmth and use but everyday it would take almost 8 miles to get it to run right at the lower throttle openings and it would not idle.

            Some carb spray and compressed air and it runs like a champ. The bike is still a little cold blooded. I start with half choke and give it 30 seconds or so then take off with it partially on choke for about a mile taking care not to rev to hard as I lower the choke to off and away she goes. I never believed in letting things sit to warm. Takes about a full 2 miles before she is really in her sweet spot and I have done several hundred miles since the re cleaning and she has been great. You may just want to take a quick look at your low speed openings again. Since you have pods it should be bone easy to get those carbs out.

            Comment


              #7
              Originally posted by UKPR1 View Post
              That being said: she warms for a few minutes on partial choke in the driveway and off I go. The first couple of minutes after that is what I have a question about: she surges and runs rough at low/medium speed/throttle until I wind her up a few times and then runs smooth throughout the RPM range. Is that a normal running condition? Bear in mind that I am riding in the South FL sunshine with temps around 80 degrees. I'd be happy to blame the jetting but thinking logically, why would the running improve once I get the RPMs up there a few times? As I sit here typing, perhaps what I should have done was apply the choke to see if the rough running continued - would that be a worthwhile trial to conduct? Haven't done complete plug chops, but plugs I have read at idle say lean. Again - if I am lean, it doesn't seem to affect running beyond the first few minutes.
              Anyway - thanks in advance. Just seeing if I'm missing anything. Haven't synced the carbs yet and there are small rpm changes when I spray around the carb mounts - so obviously two areas I still need to address.

              Thanks again.

              Geoff
              That is definitely lean on at least the pilot circuit. Starting your bike in the 80F temp range should require no choke or only partial choke just to get it to fire, then no choke at all as soon as it lights. For comparison, at 10C (50F) I start my 1100E on full choke, immediately drop to less than half choke as it tries to rev off the tach and then no choke at all after maybe another 30 seconds or so. It will idle fine with no choke from then on. At 80F I wouldn't touch the choke to start it.

              Pulling the choke while riding is a decent test to see how your jetting is. If it stops surging then you are lean, if it bogs slightly you are pretty close and if it falls on its face you are rich. It also sounds like you need to seal up some air leaks before sorting the jetting. You will never get it right until those are cleared up.

              We need to know what jets you have in there (pilot and main), where your pilot mixture screws are set and what groove the needle is set on if we are to help sort things out.


              Mark
              1982 GS1100E
              1998 ZX-6R
              2005 KTM 450EXC

              Comment


                #8
                The carbs will be back off on Friday when the wife will be out shopping . I'll pull the bowls off and note what I have. As I said before, I think I saw a 150 on one of the main jets, but nothing on the others - I could be wrong though. I'll make sure this weekend and report back.

                Thanks to everyone!

                Geoff

                Comment


                  #9
                  So in looking ahead: logic should have/is making me look into replacing the jets as a matter of course. I know I have the tried and true option of the Dynojet Kit, or sourcing my own jets if I know what I need. I'm hinging on the fact that I did see 150 on one of my main jets but none of the others, so I think I would be ok with ordering jets either side of the 150 size (DJ has a great deal for 10 jet sizes for $30). The kit may be my best bet, however, as it includes the needle and I don't think I can get my hands on an adjustable needle for my needs, any other way (it's been said by members that they is what you're truly paying for in the DJ kit). Here is my question however: the kit addresses slow running (I assume) with small inserts called Main Air Correctors. My confusion is that others have (and intuitively so...) discussed handling lean slow running with upping the pilot jet size from a 42 to say a 45 or 47. I have to say too, that a small part of me hates to glue in any type of restriction like the correctors that might be difficult to remove later. Is this Corrector an important piece to install and/or can I buy a selections of pilot jets and install those instead? Recall that I have the CV carbs.

                  I tend to get a little wordy...my apologies.

                  With Thanks,

                  Geoff

                  Comment


                    #10
                    Originally posted by UKPR1 View Post
                    My confusion is that others have (and intuitively so...) discussed handling lean slow running with upping the pilot jet size from a 42 to say a 45 or 47. I have to say too, that a small part of me hates to glue in any type of restriction like the correctors that might be difficult to remove later. Is this Corrector an important piece to install and/or can I buy a selections of pilot jets and install those instead? Recall that I have the CV carbs.

                    I tend to get a little wordy...my apologies.

                    With Thanks,

                    Geoff
                    The kit is designed to work with the air correctors so I would say you should use them. Never having used the Dynojet kit I don't know exactly what they are correcting, so I can't say if you can work around them or not. Yes, you are mostly paying for the adjustable needle when you buy a Dynojet kit. You don't need to tweak the pilots much because the idle airflow doesn't change much regardless of what you do with the intake and exhaust restrictions. At most you would need to go up one size on the pilot jet and then adjust the mixture screws to suit.

                    FWIW, you can jet for pods without a Dynojet kit, but you must have an adjustable needle. If you have that then the kit is optional. My Canadian model 1100E has an adjustable needle as OEM so I used it and bought jets separately and did it the old fashioned way. It runs very well.


                    Mark
                    Last edited by mmattockx; 11-21-2017, 11:23 AM.
                    1982 GS1100E
                    1998 ZX-6R
                    2005 KTM 450EXC

                    Comment


                      #11
                      Thank you, Mark. I'm getting a better picture of what I should be doing/should have done.

                      Good stuff.

                      Geoff

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