OSSA

As the title states, I'm looking for a particular TR250i map. The exact name of the map is "20130727_OssaTr250i_Evo2.rom" I have two ostensibly 2014 model year bikes. The early TR250i came with the EVO2 map. The later TR250i came with dual maps. I have tried all available maps and the one I prefer is EVO2. Does anyone have that map file? I have not seen anything between EVO2 and EVO6. So I'd be willing to try EVO3, 4, or 5 if they exist. Thanks in advance!

Hi Guys, My 2012 Tr280i Ossa shut-off while riding and did not want to start again. I’ve already check the spark plug (was dirty/black), checked the air filter (was clean) and checked that the gas pump was working and it was. Then, I replaced the spark plug … but still... doesn’t want to start. I guess the next step to test should be whether there is electricity or spark being generated?... however. the spark-plug cap is so deep that it seems pointless to put it against the frame and kick it to check it (as on a regular carb bike) + this one being a fuel injected… I don’t know whether the best thing to check is through the “Diagnostic Software” ? or is there any othe…

I have a 1975 250 MAR but the rear brake has 25mm wide shoes which i think was from earlier models (?), InMotion only stock 30mm wide. I am assuming these don't fit but i can find plenty of Y503 shoes that are 110 x 25mm and cheap too for genuine EBC, has anyone tried these or am i left with finding a local relining company fr the solution? Any help gratefully received, Ian

Hi all, I went for a rather long ride and both my brakes seized up. At this point, I'm focusing on the rear. I thought maybe it was the weight of the lever acting on master, making the rear brakes drag and heat up. Should there be a return spring on the rear pedal, if so where does it go? Thanks in advance!

My OSSA MAR 250 has Harpowa (Kershan Bradford) reed valves fitted. Does any body know where I can get replacement blades (petals) for them (UK) ?

At my first trial today which I thoroughly enjoyed,(Thanks Loughborough club) I lost a swing arm spindle bolt (Shame on me for poor preparation). But when we dug a little deeper it seems really strange that the position of the rear brake pedal is effected by the chain tensioner and by default chain tension. I'll blame this for my ineptitude to find the rear brake pedal for descents. Is this really correct. Thinking of removing original tensioner and fitting an aftermarket one to disassociate the 2, so the chain tensioner tensions and the brake pedal brakes, and I can fix its rest position in one place. Have I not got mine set up correctly, is it missing somethin…

Hello, bought a Tr280i over a year ago, unaware (didn't check!) that the parts were difficult to get hold off. Changed oil this weekend only for drain plug to shear off, managed to get it out! Can't find one on google, trials and tribulations sold out.... Anyone know if a gas gas or other bike will fit? Outside diameter is 11.6mm, but its not M12, could be BSP, NPT metric fine.....not sure, just hoping another bikes will fit thanks

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 any…

Hi all, I have a 72 ossa mar mark1, in 2017 I acquired the bike, I renewed the gear oil and from that point onwards my clutch sticks,when cold and to re-release it I need to rock the bike back and forward,my question is what is the correct oil I should be using for the gearbox/clutch, thank you for your response in advance, Ed

Hi, can anyone shed light on my question? Ive an Ossa 250 MAR 1976 model, I’m having trouble with starting it, it was running ok then died, on kicking over the spark looked weak, suspecting electrical failure I tested HT coil which seams ok, I stripped down and removed the stator. I’ve tested this and seams ok no open circuits. I am wondering, as the ignition is supposed to be Electronic, why are there points and a condenser fitted to the stator? Please can you help, I’ve posted a picture of the stator. regards Steve G

Hello ossa people, I have recently had my 125cc TRI 2013 engine all rebuild because the crankcase was all split open at the air-inlet side below the cilinder. Now I got it back with a new crankshaft in a new case. When testriding I noticed I didn't have power and I can not get the frontwheel of the ground like normaly. I was told by the store that it takes at least 10hours to losen up the new crankshaft so that my horspowers will return to normal. When opening the throttle I notice how the RPM's are slower comming up. Indeed it feels that the engine is so tight that the piston is not running lightly. Mecanicaly the gears and clutch see…

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...

Hi just joined so you are probably fed up with the usual requests. I’ve just bought a n Ossa 250 MAR, I need basic information as there’s no manual for it. I would be grateful of any information you can provide 1 ). Petrol to 2 stroke oil ratio. 2). Gearbox oil quantity 3) spark plug and points gaps 4). What should the compression ratio be . Many thanks Steve G.

I'm helping a friend of mine to rebuild his Ossa mar we have got to the point of starting it but even though it fires up ok it refuses to rev up, we have the correct needle and jet in the Amal carb but as the throttle is opened it just seems to spit out fuel from the carb and doesn't rev up. The timing is set at approx. 3.5mm btdc and the bottom end has been rebuild by an old school motor bike engineer are we missing something obvious ? Any help would be appreciated.

Hi, does anyone know the metric screw thread for the lock nut that clamps the top yoke to the lower yoke column? I think it is metric fine or extra fine but am struggling to find a half nut for it, it definitely is not coarse. Many thanks SB

Hi. For those who want to know how to disassemble the gearbox, the pinion must be heated to about 200ºc. Now I'm going to change the bearings. They are references of Gasgas. MT280236158 MT280232043 Cheers.

I have recently picked up a non running Tr280i that has been hand balled though a number of people of the last year or so. I was told it may have a clutch issue. After inspected it I found the clutch was completely missing. The only parts there was the hub and basket. I can buy the plates, fingers and a local shop is conforming the availability of the pressure plate and support plate. However I'm having an issue trying to find the clutch spring (number 12 in the part diagram #2420020212) does anyone happen to know where I maybe able to find one or does anyone have a bike they are parting out? I also believe my gear selector spring (number 20 in the parts di…

Have old ossa dirt bike need to identify what year it is and what size motor it hy

Never was a fan of green!

Just purchased OSSA TR77 green frame tank etc. Looking at total rebuild and have some questions. What is the RAL number of the green? Also RAL number of the black cycle parts? I would be most grateful for any information.