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IDC

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Everything posted by IDC
 
 
  1. Are you sure that the frame and engine numbers start with 70**** and not 72****? If the numbers start with 72 it is a 1980 TR77 250, mine is a 1977 TR77 engine and frame number starts with 63**** so it could be that later bikes had longer forks or the forks are from another machine altogether?
  2. If it is a TR77 then the stanchion length is 585mm ( I have just measured the old ones off my bike to check) In-motion and Feked do replacements https://www.inmotiontrials.com/product/fork-stanchions-pair-ossa-tr77-tr80-gripper-betor/ https://www.feked.com/ossa-mar-fork-tubes-stanchions-250-350cc-tr77-tr80-models-585mm-x-35mm.html refer.
  3. IDC

    Spoke angles

    Are the spokes new or are they the original ones from the stripped down wheel? In general the inner spokes will be slightly less than 90 degrees and the outer ones will be slightly more than 90 degrees. If you are going to rebuild the wheel you need to know the offset between the hub and the rim and then adjust each spoke angle to accommodate. Fit the inner spokes first maintaining the offset and then fit the outer ones again maintaining the offset, then tighten and true the wheel. Regards.
  4. Hi Sid, attached pictures as requested, the thing to note is that the outer cable gets pushed to operate the brake instead of the inner cable being pulled. Regards, Ian.
  5. Hi Woody, thanks for your thoughts. I have removed the mudguard brackets but it has not made any difference to the spacing between the fork leg bosses which is 106mm.The spindle assembly including the spacer and speedo drive is 110mm, so there is 4mm too much somewhere? I am at a loss to know what has happened as the wheel was on the bike when I got it, I should have paid more attention when I removed it! I can only think I have mixed up something in the months the wheel has been off or the fork legs were forced apart, I think it will just be one of those mysteries. Regards, IDC
  6. I am in the process of rebuilding my TR77 and have come across a problem whilst trying to re-fit the front wheel. The hub/spindle assembly is too long to go between the fork legs, please see attached photos. The only thing I can think is that the spacer between the speedo drive and the ns bearing is too long? The spacer I have is 17.5mm long 20mm od and 12.5mm id, Ossa part no 106604 which I think is common to MAR versions as well. Has anybody got their front wheel out at the moment and if so can you please confirm the dimensions of the spacer on your bike. Thanks.
  7. Ratios are on attached photos plus some other info you might be interested in. Regards, IDC
  8. In motion do a set of pushrods if you are interested https://www.inmotiontrials.com/product/clutch-push-rod-and-ball-set/ refers. Regards.
  9. IDC

    Ossa TR 77 Swinging Arm

    Thanks for the comments guys. I have now managed to remove the spindle by cutting off the flange on the bushes and carefully drilling down between the swinging arm and the spindle in multiple places to relieve the grip the bushes had on the spindle, I was then able to recover the o-rings and drift the spindle out. I cannot believe how tightly the plastic/nylon? bushes had gripped the spindle, it would not move. Whether it was due to some chemical reaction between the bushes and the grease that had caused them to swell I am not sure, they spindle has probably not rotated/moved in excess of 25 years! The hole on the top of the swinging arm is a plain hole and originally there was some dense foam type material that plugged it, on the underneath there is an oil/grease nipple with a spring loaded ball bearing in the center. I think I will tap the top hole and fit a grease nipple where it will be more accessible.
  10. Not sure if these are the same but the attached photos show spokes of my TR77. Regards.
  11. IDC

    Ossa TR 77 Swinging Arm

    Hi ColinPybus, thanks for your comments. I have still not managed to extract the spindle from the swinging arm bushes, it is seized solid will not budge even with a big hammer and a drift. I am now thinking of carefully drilling the bushes between the spindle and the swinging arm to weaken the grip the bushes have on the spindle. Hopefully I can do this without damaging the spindle or the swinging arm but if the worst comes to the worst I note that replacement spindles and bushes are available. Regards.
  12. IDC

    Ossa TR 77 Swinging Arm

    Thanks for the advice Woody, I will order some replacement bushes and get the big hammer out!
  13. IDC

    Ossa TR 77 Swinging Arm

    Thanks for the reply feetupfun. I was not clear in my original post, the swinging arm has already been removed from the frame and I was expecting the spindle to rotate in the nylon bushes easily but it seems seized. I am not sure how much force to use to extract it just wondered if anyone else has found this on an MAR or TR77 and how they got around it.
  14. I am considering have the swinging arm off my TR77 powder coated and if so I thought it would be a good idea to remove the bushes and spindle. The spindle seems a really tight fit in the bushes, can anyone advise me of the best way of removing the spindle and the bushes. Thanks.
  15. IDC

    TR77 Frame Colour?

    Thanks fourex, some interesting parts on that site.
  16. IDC

    TR77 Frame Colour?

    Hi Rockheadrumple, your bike looks similar to mine.I think woody must be correct when he says the early production run of TR77s were not black framed or green. Mine is frame number B6300** (which is in the first 99 made? assuming sequential numbering)and is a light grey with a subtle fleck of black particles a bit like a metallic finish but black bits instead of silver. The center crankcases are also finished in this colour with the outer casings being plain alloy,is yours a low frame number? I am not sure now whether to try and replicate the light grey or just go for silver.
  17. IDC

    TR77 Frame Colour?

    Thanks for the info Woody. The frame number does start with 63 and is in the first 99 bikes so is probably an early example of the TR77, I think the silver will be the way foward.
  18. IDC

    TR77 Frame Colour?

    I am restoring my Ossa Tr77 250 and would like to keep it original as far as is possible. As far as I can tell the frame still has the original finish albeit rusty in places, the Ossa silver vehicle type sticker is still on the headstock along with the stamped frame number, so I am reasonably sure it has never been repainted.The build date on the sticker is May 77 and the frame is a light grey almost metallic with the tank and side panels being the usual green. Has anyone come across this colour combination before? most bikes on the forum/internet etc from this era seem to have black or green frames. I would be interested if the light grey/green is a combination that anyone else has come across and if so what colour would the mudguards have been. Thanks.
  19. IDC

    Sprite 250 Mk 2

    Just about complete now, although you can always find more to do. Time to get on with my Ossa TR77 now.
  20. IDC

    Sprite 250 Mk 2

    Hi Trialsrfun, thanks for the link to the Sprite history website, mine was registered in 1967 and as you say looks very much like the one in the picture. Unfortunately I only have a short exhaust pipe for the nearside so it will be interesting to see how it runs with that. The flywheel does have the extra weight on it and the engine seems to be a mix of 36 & 37a unless it was supplied like that which I doubt, shame the picture on the history website does not show the offside so I could see which flywheel cover it had.
  21. IDC

    Sprite 250 Mk 2

    As far as I can tell it is a 37a but with a few variations on what I would expect. It has slimline crankcases and a slimline gearbox & chaincase with the 37a type outer cover but the flywheel cover is fully cast and has a large circular points cover instead of the classic villiers cut down casting and semi oval points cover. I am just rebuilding the gearbox as on checking the ratios it was not standard 37a in fact it was mainly 31a/35a as far as 2nd and 3rd was concerned but with a 15t mainshaft and a 26t ratchet wheel! I have a spare 32a gearbox so am planning to rebuild the gearbox with standard 37a ratios. By the way there are signs that the gearbox output bearing has turned slightly in the casing, a problem which I believe from your post in 2015 that you have come across before? loctite bearing fit on reassembly should sort it out as the bearing is still a slight interference fit. The other thing I was not expecting is that it has an oval con-rod fitted to standard crank webs, I thought these were only fitted to full circle crank webs ie the Alpha type.
  22. IDC

    Sprite 250 Mk 2

    Back on its wheels at last. Only taken 25+ years!
  23. Hi section swept, as requested please find attached pictures that you may find of interest. I have replaced the flywheel cover with a standard Villiers one but still have the original? cover with the circular points cover. I aquired two Sprite trials bikes in around 1974, both in bits and built one good one out of the two, the remains of the other was scrapped. I think the engine is a 37a but am going to confirm as part of the rebuild, I was going to check the gear ratios to confirm? Luckily in addition to a red fiberglass tank I also have an alloy tank that I was thinking of using. When I get round to it I was thinking of starting a topic in one of the other sections to report on progress.
  24. Hi everyone just joined the forum. Lock down has encouraged me to start rebuilding my 1967 Sprite 250 mk2 that has been in pieces for the last 25 years and after that I have a Ossa TR77 to do so i may need some help from this excellent forum.
 
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