OSSA

Is there anyone who sells the 11 tooth MAR sprocket in the United States?

Hi, just joined site and hoping to get some help putting a tr280i back in the mud. I absolutely love the bike and the engineering, but spares are proving elusive! I need a gear selector shaft for a 2011 as when taken apart the posts that holds the rollers that goes in the selector drum on one side has snapped off! Any help pointing me towards a new shaft will be much appreciated thanks guys Pete

What are gear ratios for a 5 speed 250 MAR? Thanks.

With reference to an earlier post on here about a broken threaded boss on the right side engine casing on a 250 Mar, I have the same problem on mine. Upon further inspection I noticed the hole for the thread was a further 10mm deeper from where it was broken off. Using an M6 machine tap I managed to tap the hole to the bottom giving more than enough length and strength for an M6 countersink bolt. The only problem I'll have now is sourcing a bolt long enough! Site won't let me send pic as over 2mb big. Can this be changed or is there something I need to do? I've sent pics before no bother.

Hello there, Can anybody tell me the correct diameter and length of these rods and why does it have to be in two pieces?

Just made this today out of a couple of bits of ally bar and an old bike stand I had around for when I finally get round to rebuilding engine.

1974 OSSA MAR 250. What is the recommended spark plug gap?

Hi, unlike Bultaco I can't find any books on Ossa's, I'm mainly looking for info on the Mar range, so if you know of anything (in or out of print) I would be greatful if you could let me know the title or ISBN number. Cheers in anticipation ! NB.

My son has inherited an Ossa 250 Mick Andrews (lucky boy!) but it has no compression (got stuck on full revs, so re-bore is likely). Steve Sell is going to sort it for me but I need to get the engine out to take to him. As a newbie to bikes, any advice, things to watch out for, or sources of info would be much appreciated. Are any special tools required? Risk of damage (eg exhaust removal?). I've found the parts diagrams and manual online, but it doesn't cover engine removal. Many thanks.

Yesterday I was riding at a local trial event and bike was running fine. And then I was unable to shift in second or neutral, it was stuck in 1rst gear. I didn't drop the bike or crash it on that day. This morning I removed the transmission and I can't see what's wrong. I tried to change the shifter spring adjustment position with no luck. Unlike yesterday, now with the trans out, I can move between 1rst gear and neutral. But can't go up in 2nd gear. Any idea of what can be the problem? I seached on the internet but didn't found anything similar.

Does anyone out there know what size flywheel puller I need to remove the flywheel on a '72 250 MAR? From what I can roughly measure, the inside diameter of the flywheel is 26mm. Not sure about the pitch.

I need to pull the magneto flywheel off on a '72 250 MAR. Probably a silly question, but which direction do I turn the flywheel nut? Clockwise or counterclockwise.

I am trying to track down a bike that turned up at a Dabbers trials a couple of years ago It is a Scimitar Ossa. It was built around 1972 by Edgar Stearn nr Cambridge and was a re-framed Ossa with bespoke seat & tank. If anyone knows of it's whereabouts, it would be good to see the bike again.

Hi, last time out on the Ossa Mar it decided to pack up, after stopping, I tried to restart it but it would only kind of four stroke with the throttle wide open. Back home and the bike cooled down, it would start and run ok for a few seconds and then start four stroking and cut out. I changed the coil with a good spare one I had but still the same, when checking the spark it was very weak. So I ordered a new electronic ignition to replace the notoriously troublesome Motaplat electronic system, with the new ignition fitted the bike started first kick, the problem I have now is the bike lacks throttle responce to the point that it would be useless, on the old system it was …

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.

Can anyone advise if the longer fork tube for the TR80 will fit the MAR legs please, and also are the fork caps the same thread? (think the TR80 caps are different) Wanting to use on a Triumph project. Thanks

Hello everybody, could someone please tell me lengths of spokes I need front and back for a 1975 250 MAR? I know I can buy them off the shelf from in motion but don't want the expense of stainless steel . Best regards, Colin.

Hi Guys, I have an issue with my TR77 350 clutch is working okay select 1st gear ok pull away but while moving can not go up the gearbox, the same when I stop moving and the bike is running. when the bike is not running I can click it up the gears by hand. ??? anyone had this before or know what the issue could be, im unable to split the crankcase as do have the know-how leave that to the pro`s. Any suggestions of good engine builder who could have a look, im based in Hemel hempstead. Many thanks Rick

Is it possible to fit an electronic ignition to a 1975 Ossa 250 MAR? If so where can I get one ? Failing that has anybody got a points ignition set in good condition that I could buy? I'm based in England . TIA

Hi there, I have 2013 TR That is extremely hard to actually get kicker to move. I I have a 9 V system starts first/ second kick but 5 out of 10 starts I’m stomping on the kick start lever and still can’t get the lever to move. I can put my whole weight on and just bounce me off really worried it’s gonna break is there a reason