January 30, 20242 yr Restoring 250 OSSA (believe it’s a TR77). Fork stanchions are pitted and could do with replacements. They look like Betor 35mm but the stanchions measure 610mm, replacements stanchions for TR77 are listed as 585mm. Anyone come across 610mm stanchions fitted to OSSA?
January 30, 20242 yr If you can't source replacement stanchions, these guys seem to do a good job : https://www.brooksuspension.co.uk/motorcycle-fork-rechroming-service-for-stanchions-both-legs?gad_source=1&gclid=EAIaIQobChMI8J2GouiFhAMVFpRQBh1qgggNEAQYASABEgLBn_D_BwE
January 31, 20242 yr 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.
January 31, 20242 yr Author If it’s not a TR77 Verde, then any idea what model had 610mm stanchions? The OSSA frame and engine numbers are 700078, Green frame, gold wheels and Amal MKII carb.
January 31, 20242 yr 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?
January 31, 20242 yr Yes that's a TR77 Verde, the number run begining 70 for the 250 isn't listed on the Ossa reference sheets The MAR had shorter forks up until 1976 when the MK3 was introduced with laid down shocks and forks which were about 2" longer and these forks were also fitted to TR77 and Gripper - 2" is about 52mm which ties in with the length of the different stanchions sold by In Motion which differ by 50mm. (The part number for the stanchions is the same for MK3 MAR and TR77) I don't know which model, if any, uses 610mm stanchions, maybe one of the motocross or enduro models Normally on the MK3 MAR, TR77 and Grippers, the forks are raised by about 2" through the yokes as they are too long and give the bike a stance like a chopper. In the photo yours looks to sit level even though the forks aren't raised. With stanchions 1" longer again you'd expect the bike to sit really high at the front, but maybe it's an illusion die to camera angle
February 1, 20242 yr Author Thanks Woody, all very strange. Pic of the bike upright, looks about correct with stanchions flush with top yoke.
February 1, 20242 yr It doesn't sit too badly if they are the 610mm stanchions as I'd expect it to be more raked, but to ride they need to be raised in the yokes, or they steer like a barge - you can see how much room there is between the bottom yoke and mudguard for 6" of travel I wonder if it has shortened damper rods to compensate for the longer stanchions. Bit of a mystery nonetheless. The fork bottoms are correct for that bike
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