Announcement

Collapse
No announcement yet.

@68 isdt

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

  • #16
    Originally posted by Brian Catt View Post
    My theory is that you need to add some packing in the expansion chamber and a box on the end. If you look at other manufacturer's ISDT bikes, they have very big chambers. This suggests to me that the "free" area in the chamber must be maintained for efficiency and the packing added outside the expansion area. The Challenger exhausts were very small in comparison to other makes, with the resultant crack being noticeable. If originality comes before function, then it seems a problem for road or modern enduro riding.
    Good point there Brian, look at the size of the exhaust system on this MZ. The continentals certainly put a lot of thought into the design of exhausts,
    Attached Files

    Comment


    • #17
      PeterGreig I sent you a PM some days ago but have not had you response, look in your PM box.

      Comment


      • #18
        Tail end "stinger" now fitted- started with a piece of tube & a sheet of .9mm
        mild steel, works to quieten the crackle, have to see if it makes any difference to the power output. No complaints about my welding, please!. I would put a pic in if I knew how!

        Comment


        • #19
          Originally posted by PeterGreig View Post
          I would put a pic in if I knew how!
          Peter. As I believe you are a GRA member you need to contact Rob (Thornton) to get upgraded on here as a full member, you should then be able to post pics.

          Thanks for your call today and the chat. With regards to the previous owner of your Challenger ISDT (UPA23F), Chris Norton, I do not have the programme for the 1971 Welsh 2 Day Trial (I first rode in 1972) so could not look him up, as you said he rode as number 73. Maybe Brian Catt has the programme and results.
          Last edited by John Wakefield; 27/07/2018, 08:30 PM.

          Comment


          • #20
            YES, I do indeed have the programme (actually 2 copies!), but no results other than my scribblings in one that show the major class winners etc. Sadly Chris did not score on that count, the 250 award going to Dai Jeremiah on a Bultaco.

            Comment


            • #21
              ISDT Greeves

              Thank you, Brian.

              Comment


              • #22
                I have upgraded you to GRA Member Peter.

                Comment


                • #23
                  Thank you Rob.

                  Comment


                  • #24
                    Probably a stupid question but how do you post pictures? Ex professional photographer, used to smelly stuff in the dark, struggle with these modern methods. Peter.

                    Comment


                    • #25
                      Go to "Manage Attachments" box (below your typing box) and all will be revealed.

                      Keep the file sizes reasonably small or the site may reject them, or if they get through they may be too big for the page.

                      8" x 6" at 200 dpi is ample.
                      Last edited by Colin Sparrow; 05/10/2018, 03:37 PM.
                      Colin Sparrow

                      Comment


                      • #26
                        I had tp make a "stinger" silencer from scratch as I could not find anything suitable, so starting with a piece of tube and a piece of flat...…. this is what I came up with. No comments will be accepted about the quality (lack thereof!) of the welding I am still trying to get to grips with a new mig welder. The crafty bit was using gungum exhaust repair putty to join the extra to the original- means it can be removed for originality for show purposes & replaced for road use. I will let you know how much difference if any it makes to the performance. Peter.
                        You may only view thumbnails in this gallery. This gallery has 4 photos.

                        Comment


                        • #27
                          Looks a neat job Peter, (apart from the for mentioned weld) maybe what Greeves should have fitted back in the day, amazing they got it through the noise test back then.

                          Comment


                          • #28
                            Originally posted by pgc40 View Post
                            I had the same problem with my ISDT challenger exhaust being too loud so I saved the original and bought a replica exhaust pipe from CW classics http://www.cwclassic.co.uk/gallery-bike-parts/ for £180 which took 4 week for them to fabricate. The tail pipe or stinger was a larger diameter than my original exhaust so I was able to fit an internal baffle (as suggested by Stace on this forum) which I bought off ebay https://www.ebay.co.uk/itm/1pcs-48mm...wAAOSwL3JawzHy and packed it with wadding. It is a lot quieter now and looks just as good as the original. The replica challenger exhaust pipe was painted using a spray can of high temp matt black used for painting barbecues that I bought from my local DIY store. Just make sure that if you buy a challenger exhaust from CW Classics that you tell them what size diameter your header pipe is (or better still send your header pipe to them so they can snuggly fit the exhaust to it without any air leaks at the joint). Although CW Classics say that the new challenger exhaust pipe comes with an internal baffle already fitted; it is just as loud as my original so I had to fit another baffle in the tail pipe.
                            Thanks PGC40, just got myself a couple of silencers from where you recommended.

                            Comment


                            • #29
                              Originally posted by Bearingman View Post
                              We Built this MX5 clone for a customer who was going to ride it in the ISDT reunion ride. My attempt was to make it quiet as possible without adding a large silencer. Since the pipe was made from scratch, we lined the inside with perforated metal cones and wrapped these with fiberglass silencing cloth. On the exhaust tip we used flexible stainless tubing with slots cut in it and again wrapped it with more fiberglass cloth. For the tail piece, we used an FMF USFD approved spark arrestor that is used in a modern four stroke exhaust. While it looks the part and fits really well, it's still a little noisy to my disappointment as a lot of work went into the fabrication. I should have used more cloth, but did not want to turn the power into a total slug.

                              Kenny Sykes
                              Nicholson Motors
                              Bike looks familiar Kenny.

                              Comment


                              • #30
                                Hi Peter what 68 ISDT Greeves @ San Pellegrino do you have? Is it an Anglian?

                                Comment

                                Working...
                                X