OSSA

I can bring my software/interface to the Kingman World Trial if anyone needs to give their OSSA a tune. I don't know my route back up north- so a possibility I could stop by if you live on my route. Mark

Should the rear mudguard fitted to a OSSA TR77 be full length, as in down to the swinging arm or the shorter type. I am thinking the Gonelli type mudguards. Now to the middle exhaust box, should this be packed/repacked with exhaust wool or is it an empty expansion box with a baffle tube inside?

I have Pirelli MT43 tyres to fit on my OSSA MAR mk3. What tyre pressures should I use for road use?

Confirmed

Almost finished my rear suspension linkage clean and lube.Are there supposed to be a pair of spacers on either side of the top shock mount? I'm sure i didn't take anything out and can't find any in the parts manual.

which model/year 280 has the upside down forks as pictured: http://lewisportusa.com/ossa.htm

Is there an emissions sticker for these bikes? I couldn't see it anywhere... I have a 2012 Explorer, but I suspect that TR280i would have it in the same location. Thanks!

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

Found this video. CLICK ME

I have studied the parts diagram and notice there is a plastic tube inside the gearbox with slotted ends that serves as a gearbox breather. In my cleaning up of this old machine, removing concrete like mud, I have yet to find where this breather vents to ambient outside air. Could someone please explain where the gearbox breather vents externally? Thanks

Here in the US, 7mm fasteners are not common. Not that I need many, but is there a reasonably priced source for this size fastener. The real oddballs I need, since I had to drill them to remove the skidplate, are the 7mm flush head slotted screws.

Several members have ask me for help with Mapping/Upgrading issues. I'd be a lot more willing to experiment if I had an "expendable" ECU laying around. It does not necessarily have to be fully functional. I realize this is a long shot, with the small number of bikes built, but I'll put whatever I learn into the public domain.

Had a lot of fun at a Trial this weekend.

what do you think? - just thought i'd throw in some positive balance...

The bike is together, and now has a bit of ride time around the yard. No issues, and very pleased with it. When I went to buy spark plugs weeks ago, I thought I got the correct one. I searched the internet quickly and found recommendations from heat range 8 to 5. I read that BP6ES was correct, and it did cross reference to the ages old Champion N9YC I removed. I now suspect, having seen other references to BP7ES being correct. I have pretty much ruled out the heat range 5 and 8. So, for a 1973 MAR 250, is it a NGK BP6ES or BP7ES? Ready to get the jetting fully sorted out, and prefer to do it on the truly correct plug.

Hello, i am wondering what is the factory fitted hydraulic clutch oil? I cant find data anywhere in pdfs. Will lhm+ or magura blood fits?

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.

check out the new web site they have upside down forks i think they will have some problems there and i also think they might have some problems with the air box it looks to go straght in to the throttle body and it looks like it gos straght down i think mabe it will hold water??

Hi just wondering if anybody knows the size of taper roller bearings that will be required to fit an Ossa Mar 1977 ish ? thanks

Hi, back in the end of the 70s, I had an Ossa MAR? which had a yellow tank with a black stripe round it, similar to the MAR design, does anyone know who supplied them with a yellow tank? Thanks for looking. Dave