OSSA

I am so grateful for the help I received with my gearbox I want to give something back to this forum. I'm a retired electrical engineer and a hobbyist machinist. I have done a fair amount of work reverse-engineering the TR280i's electrical system. Cheers. I have replaced the .PDF file with an entire website: https://www.ossa-efi.com/home It corrects some errors and omissions as well as providing greatly increased technical content.

Hi Guys, just wondering if anyone can help me out, I am after a sprocket side cover 1971ish Ossa Pioneer sprocket side cover. If anyone has one or knows of someone I can contact that would be a great help.

I’m working on a 2014 280 (Explorer)- inner O-ring is bad so I need new ones. The ones I got are too large. I think they are 82 mm and 104mm (have to measure diameter). Does anyone know the correct size and if any GasGas O rings are correct? Otherwise I guess I’ll have to source some Vitron O rings at Granger or something (States).

I have an OSSA that has come from Italy. It was sold as a 250 , which I beleve it to be, but today at a trial it was pointed out that as I have cutout on my fins, that it may be a 350?? The engine no. Matches the frame no. But the number doesn't show up on any of the lists I have seen. Any info in aging the bike etc would be appreciated. Or even recommended upgrades, mods etc...

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?

Penso che sia una buona idea indicare dove acquistare le nostre parti di bici https://www.zonetrial.com/Articles.aspx?langue=E&MarkSelected=Ossa&topic=0 https://trialstribulations.net/index.php?main_page=index&manufacturers_id=7&sort=20a&page=3&zenid=6od90vt7vtam74t4n365i36kv7

Can anyone help to identify this crank which was in a box of Ossa MAR bits. Seems different and a lot smaller to the MAR & TR I've got. Any info appreciated.

I found a barn fresh MAR with mostly original equipment and under 1250k fresh motor. It's worthy of a full restoration but I was looking for a cheap rider so I am bagging/boxing all the nice original bits and going to ride a season or two before doing the restoration. It's got spark, compression and carb is clean. It had no brakes or fuel tank so I hasn't been started. Rare find in these parts by barnstormerbikes, on Flickr Rare find in these parts by barnstormerbikes, on Flickr The bike had been stored with ethanol fuel and the tank was mush. I am using Caswell epoxy liner/ shell to remediate but not sure if it will work, assuming it will. I have already r…

Hey guys, I just recently got my first trials, a 2013 TR280i. The previous owner rigged up a start assist with a 9v battery and when I went to swap for a new battery a few of the wires came apart. I am clueless when it comes to electronics so I have no idea where to even start re wiring. I tried it a couple ways and has had no luck, and now the start assist isn’t working, nor is my fan turning on. If anybody could help me figure this out it would be much appreciated.

Hi, I have a 2012 TR280i bought used last year. The bike ran very good and started in the 1st or 2nd kick every time until recently. We were riding in our regular spot and after a big rev the motor died. We thought it ran out of gas but after topping it off (it did take a full tank so maybe it did run out) it would not start. It's getting spark and the fuel pump is working as it will spit out gas from the fuel line when kicked. i figure the next thing to check is the injector but it seems to be impossible to get to with our removing the tank and radiator. I say this because the ECU is wedged in between the frame and injector and there seems to be no way to get …

Well, I sold my 2014 Explorer last week. I really have liked that bike- LOTS. It has been pretty darn good, with the linkage the weak spot for how I was using it. If they had a more robust linkage with real bearings, I think it would be a LOT better. No engine problems at all, just a broken return spring for the gearbox. I had no plans to sell, I even bought a Beta 4T to ride so I would not put so many hours on it. But most of my buddies ride enduro bikes, so after getting a Beta Xtrainer, I found I just wasn’t riding the Beta 4T trials much. So I sold it. Someone was interested in the OSSA- and I decided to give electric a go. Electric-Motion has a mo…

Hi. I was hoping someone could help med with a problem I have. After winter storage my 2013 Ossa TR300i keeps boiling. Fan won’t start but I’ve tested it out and the fan works with direct power. I’ve read multiple post’s on this but still can’t figure out what’s wrong. I’m no pro when it comes to MC engines so I’m having some difficulties figuring out everything. I was thinking of sending it to service, but found out that it cost almost as much as I gave for the bike so I’m hoping I can fix it myself. Thus far I’ve checked all connections and they seem fine. I’ve ordered a can of Evans waterless cooling hoping it will stop the boiling but i think I should fix …

Hi guys, After soom advise on what fuel mixture to run in my TR77 350, been a long time in coming but final got out on my bike this weekend after 30 years in boxes. i'm running it at 40:1 mixture and leaving clouds of blue smoke in my wake. Thanks Rick .

Another Ossa MAR basket case project and daft question's but I'm guessing that hole is not meant to be there??? If so why drill a hole? Does it need to be welded or can I bung it ?? I've got 2 engine's 1 with broken con rod and this one which is almost there but with a hole in the crank case. Just my luck. Your thoughts appreciated ?

Currently working on an Ossa MAR basket case & TR77 basket case (punishment I know) but not sure if this exhaust is off either....Can anyone help identify please?

I have a customer 2012 Explorer (with fixer nut). It was stuck in 6th, I popped out the gearbox and found a broken gear. 6th drive gear tooth/engagement dog if I have it right. It appears on 6th the teeth just extend out to make an engagement dog. Not very thick there so seems a weak spot? But I always tell people to shift this slowly and gently and they will last great. Start ‘jamming gears’ like an enduro bike and you could probably break it in an hour. I had almost 400 hours on my Explorer (just sold it)- only gearbox issue was a broken return spring. Edit: Dang, I forgot the original reason for post. Who has gearbox parts? I have a call into Lewi…

HI , Im restoring an OSSA TR80 and looking for a sump guard for it . Thanks .

I'm contemplating buying a 2012 tr280i, but am concerned about the spares situation now that the factory is closed. I spoke to a chap at Trials & Tribulations who was very gloomy and basically told me not to touch it. Birketts are currently closed so can't ask them. Does anyone have any views or advice? Thanks

Does anyone have a source for 12mm x 1.5 mm male thread fuel tank petcock? I need one for my OSSA MAR. Thanks, Jim

Quick question, are OSSA still trading? Havnt seen anything on recent videos on youtube from anyone. Obviously there are no OSSA riders in X Trials but also dont see any at amature level videos either.