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Suzuki TR500 replica Period 4 Historic race bike

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  • Suzuki TR500 replica Period 4 Historic race bike

    Well, I can see this is probably going to be quite a long project, but as they say, you should always start with the end in mind. So this is something like what I am aiming for. A TR500 replica circa 1972 (the air cooled version) eligible for Period 4 historic racing.



    Back in 1971 I briefly raced the 250 version and for years have wanted to relive those "glory" days! Talking to the marital control board about it, she questioned whether I would be happy with only a 250 after racing a Supersport bike so after some careful thought (about 3 nano seconds) I agreed that a larger cc might be more enjoyable. I briefly toyed with the idea of a TR750 replica, even a widowmaker Kawasaki, but kept coming back to the 500 as a more doable and cost effective project as they had proven reliability and reasonable, if not outstanding, performance. So bang for buck, a 500 it was.

    As I am living in the US at the moment I decided to start my quest here as parts seem to be quite cheap compared with Oz. Of course I will have to add the cost of freight back home when the time comes, but I think it will still work out cheaper. And so to ebay where I have spent many lonely hours scouring for bits. Got to shop around as prices vary significantly!

    As a start I have bought a T500 frame and swing arm ($75US),
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    a rear wheel ($45US),
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    front forks and triple clamp off a GT550 as this gives me the twin disc setup ($122US), a GT550 hub (already drilled for 2 disks, $60US), The discs themselves ($50 the pair) have come off a GT750 water buffalo and they have been sent to a machine shop for 36 hole drilling which is essential for wet weather stopping, this will set me back $110US. A set of calipers off a GT750 for $35US (these will need a rebuild kit) completes the front end. I will probably mod the forks with racetech emulators and better springs at some stage.
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    The guy I bought the frame off just happened to have one and a half T500 motors also which I picked up for $200! I haven't seen them yet, but as the motor will be totally stripped down and rebuilt, as long as they are basically OK, that will do.

    Next item on the list is the aluminium flanged rims and spoke to build up the wheels and some racing brake pads and shoes. I already have some leads for those over here.

    There seems to be endless information on converting the road bikes to a racing spec and interestingly enough, an Aussie site seems to be the most acclaimed and is hosted by none other than Perth based Murray Barnard. Don't suppose he is a PSB member? So already, some motor specs are starting to be thought about. My neighbour here in Vermont is an ex motocross tuner so we are having a great old time discussing porting and expansion chamber design. In fact he has got right into the intricacies of chamber design and I think we might be able to come up with something fairly special. I think many beer fueled discussions will eventuate before we settle on the final specs!

    I will do all the rebuild back in Australia next year so if anyone knows a good 2 stroke crank rebuilder, let me know. Also if anyone has had a go at hydroforming for the the expansion chamber?

    It will probably be fairly sporadic posts from here on in. Would love to hear from anyone who has any advice.
    Last edited by Grin; 06-10-2013, 10:44 AM.
    [SIGPIC]Accredited Motorcycling Australia Road Racing Coach Level1 TRAKDAYZ

  • #2
    Crank rebuilder; Ray Eason Bayswater!
    I used to spanner for Robbie Bron on a T500 back in the good old days.
    He came 3th in WC 500cc class 1971 behing Ago and R. Turner (NZ).
    Brilliant bitta kit.
    Looking forward seeing it next year.

    Comment


    • #3
      One of the guys at work used to race a TR500 in NZ "back in the day". Unfortunately he snuffed it a year or so ago, so I can't put you on to him (other than via a seance) There aren't as many around as I would have thought, so - good choice. Will watch with interest.
      “The truth is incontrovertible, malice may attack it, ignorance may deride it, but in the end; there it is. - W Churchill”

      Comment


      • #4
        Originally posted by Jamathi View Post
        Crank rebuilder; Ray Eason Bayswater!
        I used to spanner for Robbie Bron on a T500 back in the good old days.
        He came 3th in WC 500cc class 1971 behing Ago and R. Turner (NZ).
        Brilliant bitta kit.
        Looking forward seeing it next year.
        Cheers, thanks for the heads up.
        [SIGPIC]Accredited Motorcycling Australia Road Racing Coach Level1 TRAKDAYZ

        Comment


        • #5
          More bits and pieces arriving, the wife is starting to cringe every time she sees the UPS truck in the street! I have joined a couple of 2 stroke forums here in the States, there seems to be a really big group of enthusiasts here, they certainly have some 2 stroke pedigree, Roberts, Mamola, Lawson, Rainey, Schwantz, etc etc so I guess it stands to reason. Great to see.





          [SIGPIC]Accredited Motorcycling Australia Road Racing Coach Level1 TRAKDAYZ

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          • #6
            Following with interest, last year in NZ I went to the farm where I abandoned a T 500 frame in the seventies. Alas the shed is gone and. Modern house in its place. The frame was left over after I destroyed my T 500 on Manfield and rebuilt it from a donor bike.
            I have fond memories of the 500.

            Comment


            • #7
              Pretty sure Peter Senior has at least one in his garage, I'll ask next time I see him, he lives in the next cul de sac to me.

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              • #8
                Grin, I use to work with Murray Barnard years ago and went up the track a few times when he was building his 500's. I think the frames were out of the NZ. I will see if I can dig up a contact.

                Oh, and his 500's were very nice but he really needed you riding them.

                Comment


                • #9
                  Maxton & Seeley frames were converted for these as the Yamaha engine is not much different to the Titans.
                  Went back for a reunion 3 years ago and just went through my pictures and here is a semi factory machine.
                  Last edited by Jamathi; 15-10-2013, 07:19 AM.

                  Comment


                  • #10
                    Thanks guys. One thing about having time on your hands is that you can do a lot of research! I have made contact with Murray Barnard, Neil, through of all things an American 2 stroke forum and I am going to catch up with him when I get home next year. He lives in Roleystone.
                    Seeley were a very popular frame for these bikes and I have an article from a guy who modified his T500 frame to take in the Seeley principle of tubes straight from the top of the steering head to the swing arm mount, so I might try that. Also going to have a go at fabricating a box section swing arm.
                    The sky (or more importantly your bank account) seems to be the limit as far as modifications go with these. There are some pretty exotic parts available from special conrods ($1300 a pair), to 6 speed gearboxes ($2200), to exotic cylinder heads ($1000 a pair) and the list goes on. Electronic ignition is $600, a tank and fairing kit another $1200. Jeez, where do you stop? Probably just before the wife catches you!!
                    So I think mine is going to be fairly home grown. My neighbour here is developing a porting and expansion chamber design which I will do myself, the frame mods similarly, maybe even the wheel building (I used to build all my own racing wheels as a cyclist). Thinking about doing my own tank and seat and just buying in the fairing to keep costs down. Forks I can do myself or enlist the services of Elliott fork rebuilding! (Thanks Scott, in advance). Obviously rear shocks, carbs etc are just buy in items.
                    So, if you want a screamer (apparently upwards of 11,000rpm) you need to spend serious money, or you can limit yourself to around 8,000 and get out of it without too many exotic bits.
                    Hopefully Mr UPS will deliver me some more heads and barrels this week, Ebay is your friend!
                    Thanks for all your comments, keep 'em coming.
                    [SIGPIC]Accredited Motorcycling Australia Road Racing Coach Level1 TRAKDAYZ

                    Comment


                    • #11
                      If you are going to run the lub system, then you are limited in the porting dimensions as there are some oil "outlets" in the cylinder that cannot be messed with.
                      If you are running premix then will overcome the problem.
                      A very good ignition system is mandatory as they are very sensitive to proper timing/detonation.
                      You have to understand that they have a BIG Bore and Stroke which does not like excess piston speed nor the extra weight of the slugs!
                      This is why all the factories went to 3 and 4 cylinders for 500cc racing

                      Comment


                      • #12
                        The Suzi factory tried these, watercooled twins and that still did not work so the XR was developed, (reuse of the 50 125cc earlier GP racers technologie)

                        Comment


                        • #13
                          Originally posted by Jamathi View Post
                          If you are going to run the lub system, then you are limited in the porting dimensions as there are some oil "outlets" in the cylinder that cannot be messed with.
                          If you are running premix then will overcome the problem.
                          A very good ignition system is mandatory as they are very sensitive to proper timing/detonation.
                          You have to understand that they have a BIG Bore and Stroke which does not like excess piston speed nor the extra weight of the slugs!
                          This is why all the factories went to 3 and 4 cylinders for 500cc racing
                          Thanks Bert. I think I'm going to stick with the oil pump based on my research so yes, the porting mods will be restricted to some degree. Do you have any experience with any of the following ignitions?
                          PVL
                          Electrex
                          JL (Jim Lomas)

                          they seem to be the only ones readily available for the T500, Boyer doesn't do them anymore and I can't find a Femsa dealer.

                          I still love the look of the WC TR's, even if they weren't competitive! They are fetching some serious money now.
                          [SIGPIC]Accredited Motorcycling Australia Road Racing Coach Level1 TRAKDAYZ

                          Comment


                          • #14
                            I would definitely be looking at one of these ignition systems by borut.
                            zeeltronics
                            Drop him an email and discuss your needs, and he will steer you in the right direction for your application.

                            Comment


                            • #15
                              Originally posted by Gangus View Post
                              I would definitely be looking at one of these ignition systems by borut.
                              zeeltronics
                              Drop him an email and discuss your needs, and he will steer you in the right direction for your application.
                              thanks for the heads up Gangus, I have sent him an email.

                              More bits acquired yesterday. I did the round trip from Vermont to Michigan to collect the frame, rear wheel and the 2 motors. These will be completely stripped and rebuilt but the good news is that the 4 barrels I have are all standard bore which means there is plenty of room for going to OS pistons. The trip over took 2 days as I went via Niagara falls to take our friend from Perth to see them but drove 15 hours straight yesterday to make it home in one day. Oh the commitment!




                              I am sure the wife actually said today that I can spend what I like on the project so there will be some serious ebaying going on over the next few weeks for bits and pieces that I will crate up and ship back to Oz with the rest of the gear. I thought that was extremely big of her seeing as I forgot our wedding anniversary (again!) yesterday. She'll probably get suspicious if I start remembering it!

                              High on the list will be anything that is cheaper over here in the US and expensive to post as individual items, so things like new carbs, Wiseco piston kits as well as bits and pieces of hardware will be high priority as they can all go in the crate.

                              This week I will be stripping everything surplus to requirements off the frame as well as grinding off any lugs etc I don't need to keep the weight down - it weighs a ton!

                              About to invest in some 2 stroke design/tuning software About: Vannik Developments which according to all reports is the best available. My neighbour here is an ex motocross tuner and a whiz with the numbers and calculations so I will turn it over to him to come up with the head design, porting and chamber design as that math stuff is not my strongpoint.

                              Bought a cool (or hot) gauge the other day. It reads the exhaust gas temps coming out of the port and apparently this is a really good way of assessing your jetting - too hot, too lean, too cold, too rich. Neat.



                              More pics of goodies to come soon!
                              [SIGPIC]Accredited Motorcycling Australia Road Racing Coach Level1 TRAKDAYZ

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