OSSA

I am looking for a wiring diagram for a 2012 ossa explorer. I am all so looking for a picture of the back side of the key switch showing what color wire is installed on which terminal on the switch. At this time my bike will start in both key positions.

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

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

Hi Been having some issues with the mixture on mine, plug is always sooty black, went through new plug in a trials and a practice today, saw that the TPS was loose too, anyone know of somone in the leicester area that can reset the tps and have a fiddle with the mixture? i have had a google but couldnt see any trials mechanics in leicester at all but them i am not the best at googling. I do plod around on the easy routes so i dont make the bike work as hard as it could, i cleared it out with a quick 4th gear full throttle blast and it smoked like hell for a while. that did make it a little happier but then wouldnt idle, cleaned the plug and its all lovely aga…

Oil form gearbox comes to engine, because rubber on the bearing is bad. I changed out ring rubber, but it still dont work, and oil going to engine. Is anybody know, how to change bearing?? I dont understant how to unlock this bearing. I cant find information on manuals... I think, i need pull gear and make hot, and after pull bearing...

I’m working on fitting an electric pump to 2014 Explorer (mine in past, now sold). I’m not certainly which way the coolant flows in the OSSA original setup. Toward the top of the radiator? Or the other way?

Hi, I know this seems strange, but what CC are Ossa MARs? I have one that I have used for a couple of years, and always assumed it was 250, but could it be a 350? It does seem to pull very well, so how can I tell, without measuring the Bore and Stroke. .

My kick start works fine going down but struggles to return. It’s like the case seal has swollen up and is tight on the shaft? Any ideas what I should order in advance before removing the clutch case and investigating deeper?

Hey everybody, I've been searching for the right flywheel puller for a few days now. I need to pull the flywheel off of my 1972 Ossa 250 MAR. Im pretty sure that the thread is 26mm but i have no clue what the pitch is. Does anybody know where I can get a flywheel puller for this bike?

Need a new throttle assembly, anyone experiment with the Domino fast vs. slow on an OSSA MAR 250?

The previous owners did a good job of wiping out the exhaust threads on the side of the cylinder. One previous owner had rigged the exhaust ring to be held on with four small springs that also attach to the cylinder fins. The ring is held in place but since there isn't much left of the threads, it does leak some exhaust gas. How bad is this for running since most of what I will be doing is slow speed? Are there any short term fixes and what is the best long term fix? Thanks for any help on this. Jim

hi, got a very nice clean ossa mar 1975 250. hasnt been used much. while we have owned it we have only used it on our drive and just had it stored . well anyway it runs perfect on flat but as soon as you twist the throttle and the front lifts up or you attempt to go uphill or up a bank. it bogs badly and will cut out unless you give it even more then it will roar up at high revs. and if you hold constant throttle for a few seconds say 1/4 throttle cruising then give it more then it bogs, again you have to give it even more to get out of it. seems to me it seems to be an issue with the floats in the carb. like there not adjusting when angled or like theres not enough fuel…

Hi, Hope someone can help? Ive just purchased a TR77 250 which was sold as a poor runner with the previous owner thinking it needs new points or main seals which were both supplied with the bike. On getting the bike home it starts up very easy but struggles to rev up at all. The bike is fitted with a Dellorto carb which I presume is wrong so maybe causing bike to run bad. Can someone confirm what model of carb this bike needs if current one is incorrect and also where I might be able to get the correct one from? Many thanks, Tom.

My 1973 MAR has some corrosion on the flywheel and stator. With care, I have cleaned up the poles of the stator. To clean the corrosion from the flywheel I used abrasive cloth and cleaned the magnets and interior. I also used the abrasive cloth to clean the flywheel exterior. Removing the corrosion also removed whatever protective coating was there, so I ask, does anyone know what the oem finish was and what color a new flywheel would be.

Hi, I have a newly restored Ossa Mar that has not yet had the lighting harnesses made up and installed. I am looking for a few good pictures of how the harness are routed e.g. between the switch and the headlight, the headlight back towards the supply and ground wires, as well as from the rear brake switch and the tail light. If anyone has a MAR where these harnesses have been properly set up I would sure appreaciate a pic of them so I can know how to fabricate / install my own. thank you kindly. Paul Wells ps I have attached a picture of my bike. By the way I have the tail light, handlebar switch and brake light switch. They're just not hooked up yet. thanks again…

My 2013 factory 300 is coming in on Wednesday the manual is with it. I'd like to have the fuel ready to go when I get the bike. Is there a specific oil that Ossa recommends, or can I use the same Maxima K2 that I use in my Sherco? What ratios are you guys running? Tnx.

hi, our ossa 1975 250 mar has got a silver sammy miller exhuast on. it makes a right racket. very poppy and loud compared to our 348 mont. can you get an original one? would this be better? or any after market one?

Hi all I'm new to the forum (and Ossa's) and hope you can help. I'm restoring a TR77 that I got in pieces 15 years ago and am finally getting it together. The engine is stripped, the crank rebuilt, and the main bearings and other bearings in the casing seem easy enough to source, but I'm puzzled at the blind needle roller pictured below. Is this an open-at-both-ends bearing fitted up against a blocking end piece, or is it a one piece closed-at-one-end needle roller bearing? Also, does anyone know what number bearing it is so that I can buy one from somewhere? Is it easy to remove? Any other tips or comments you have would be much appreciated Thanks Adrian (P…

Hello everybody, Does anybody know where I can buy a Kickstarter for my 75 250 MAR in the UK? TIA Colin

Guys , newbie about to purchase Trials bike here Really like the look of the Ossa but the horror stories concerning the 11/12 model are putting me off thoughts please