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250 Griffon Build

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  • 250 Griffon Build

    So I bought this Griffon on ebay for $1200. It was a one owner bike but had sat for the last 20 odd years. Looks better in the original pic than in reality. My intention originally was to do a totally correct resto but now seeing that it will be raced and I like my bike to be different to the next guys I have decide to build it the way I like it. It will be mostly stock but with some subtle differences. I am fortunate to have found Ken Sykes (bearingman on here) who has been a tremendous help so far with info and parts.

    Here are some pics of the bike as I bought it and where I am at now with the build. I will post more details up later.
    Attached Files

  • #2
    Going to be a beauty

    John - Thanks for posting and good to see you doing it your way - with a focus on getting ready for racing - where a 250 Griff belongs !

    Kenny is the man in the US to help - and indeed has helped many of us Brits as well with our Greeves

    Looking forward to seeing how the project progresses - shout f you hit any technical difficulties- lot of expertise on this forum from the guys who race the Greeves series and also ex factory workers etc....

    Cheers Kim

    Comment


    • #3
      Well yesterday I decided to clean up my expansion chamber and think about what kind of silencer to use with it. The pipe looked in excellent condition aside from typical dirt and surface rust, however as I started to clean it with the wire wheel it is apparent that it's condition is not so great after all. As soon as I put it on the wire wheel holes started to appear very quickly Just means I will have to make a new one which is a bit of a pain but very doable. Here is a pic of the holes.
      Attached Files

      Comment


      • #4
        Originally posted by Kim275 View Post
        John - Thanks for posting and good to see you doing it your way - with a focus on getting ready for racing - where a 250 Griff belongs !

        Kenny is the man in the US to help - and indeed has helped many of us Brits as well with our Greeves

        Looking forward to seeing how the project progresses - shout f you hit any technical difficulties- lot of expertise on this forum from the guys who race the Greeves series and also ex factory workers etc....

        Cheers Kim
        Thanks Kim!

        Comment


        • #5
          I started making the patterns for the pipe. This is pretty easy when you have the original to make the patterns from. I would be interested though if anyone has or has access to the original drawings for the 250 Griffon pipe just so I can double check my work.

          Also I will be using a silencer on this bike as it will be too loud without one. Anybody have suggestions for silencers?
          Attached Files

          Comment


          • #6
            There some odds and ends of exhaust drawings in the file. There are also the drawings for an original enduro type silencer. It is either that or make up a stinger out of alloy tube. I'm trying to get my Anglian ready for Sunday and tomorrow I have a reunion which unfortunately involves beer and my bus pass so when I get a mo, I'll have a more thorough look. Just keep nagging me!

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            • #7
              Well ordered my 90* mandrel bends for the head pipe, one at 2.5" rad and one at 3" rad just as the original so when I actually get some time to work on it shouldn't take too long to knock up.

              Comment


              • #8
                Originally posted by Rob View Post
                There some odds and ends of exhaust drawings in the file. There are also the drawings for an original enduro type silencer. It is either that or make up a stinger out of alloy tube. I'm trying to get my Anglian ready for Sunday and tomorrow I have a reunion which unfortunately involves beer and my bus pass so when I get a mo, I'll have a more thorough look. Just keep nagging me!
                Rob, my biggest concern at the moment is your avatar

                Comment


                • #9
                  Originally posted by johnu View Post
                  Well ordered my 90* mandrel bends for the head pipe, one at 2.5" rad and one at 3" rad just as the original so when I actually get some time to work on it shouldn't take too long to knock up.
                  Hello Johnu,
                  Quick question as I don't want to hijack your thread.
                  I need to replace the front two bends on my QUB exhaust, can you point me in the right direction please?
                  Craig

                  Comment


                  • #10
                    Originally posted by griffon380 View Post
                    Hello Johnu,
                    Quick question as I don't want to hijack your thread.
                    I need to replace the front two bends on my QUB exhaust, can you point me in the right direction please?
                    Craig
                    No worries. I just googled mandrel bends and several places came up to order them from (I am in the USA though). You need to check the radius as on my 250 the two pieces that make up the header are different rads.

                    Comment


                    • #11
                      Craig I did a similar job on my QUB a couple of years ago,,,,,,,,,,note the original header length is slightly short and constrained ......I used two equal mandrels of same bend and slightly larger bore.........it is more df a smooth arc than the original which is effectively two 90 deg bends and a straight bit to connect......It just about clears the front mudguard - but works a treat.....

                      I also did a similar job on my 250..........John - Kenny Sykes did similar job on his 250 Griff - smooths out the sharp turn at the top...
                      Cheers Kim

                      Comment


                      • #12
                        Originally posted by Kim275 View Post
                        Craig I did a similar job on my QUB a couple of years ago,,,,,,,,,,note the original header length is slightly short and constrained ......I used two equal mandrels of same bend and slightly larger bore.........it is more df a smooth arc than the original which is effectively two 90 deg bends and a straight bit to connect......It just about clears the front mudguard - but works a treat.....

                        I also did a similar job on my 250..........John - Kenny Sykes did similar job on his 250 Griff - smooths out the sharp turn at the top...
                        Cheers Kim
                        Yes I've seen the pipe on Kens bike, I will aim to replicate his as much as possible. I've done quite a bit of pipe building in my time so should not be too difficult (see example in pic below).
                        Attached Files

                        Comment


                        • #13
                          Nice work John . The Griff pipe should be a bus and holiday for you

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                          • #14
                            Kim, Johnu,
                            Thank you for your help. I have lots to do. Posting on my thread shortly.

                            Comment


                            • #15
                              Been a slight change of plan on the exhaust. I decided to take acurate measurements from the original and draw it out so that I can get it made looking (probabaly) better than the original. When you look closely the original is a bit of a bodge up in my opinion. So now if I develop out all of my own cones I know that each section will fit up nicely with it's mate.

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