OSSA

Hi All, Looks like i'll be splitting the engine on a 250 Mar I've just acquired. It only selects 1st and 2nd ,and I have seen a posting from scotty in 2007, which had a good reply from woody. There was no outcome posted , so wondered if anyone as come across this since. Also does the engine drop out the frame easy, looks quite tight .

Hi all, just stripping down a 1972/3 MAR and was wondering if anyone could tell me the serial number for the bearings. I`ve found the number for the steering head bearings (30204) but can`t seem to find any for the wheels. Also are the hubs supposed to be black?The bike is 99% original and the spokes don`t appear to have any overspray. All the bikes I`ve seen have alloy/silver hubs but mine are black! Cheers in advance, basketcase.

The OSSA TR77 250 that I am restoring to ride has an assister spring (expansion type from round bar which protrudes from inner side of swing arm to end of chain tensioner arm) as well as the radial spring on the chain tensioner/rear brake shaft. I have seen bikes with & without this extra spring so what are you running on your bikes, is the radial spring on its own ok or does it require the other as well, which arrangement works best.

hi ,any one had much success lightning clutch action on Mk 1 mar .I have lenghtened the actuating arm on top of the crank case , and used one of those geared type levers at the handle bar .still very heavy .

As The topic says, I want too fit a long life chain to the Ossa, as I am in sand, mud and dust a lot. I am told the chain is wider by a little but uncertain as to how much and whether it will round the drive sprocket. I know I have to increase the size of the chain tensioner cage. Any clues?

I read that guys are purchasing the 2013 clutch pack. Is this the whole clutch assembly from 2013 bikes or is it just the "2.1mm intermediate plates" from the special parts catalog? What does the clutch upgrade do? I have a 2012 explorer with 2.5 hrs on it. The clutch seems fine, but shifting is poor. Up or down, any gear, Whether its running or not. It is hard to get into gear.

Is there anyway to get the front brake to work, or better yet,has anyone had any luck fitting a different front wheel? If so what was it from? It would be nice to fit a TY front wheel.

Have been thinking about buying an Ossa around the 75/76 age to compete in the Pre 77/80 class in France and Spain. Could any of the officionardos of the Marque point me in the direction of what to look out for and any sensible things/mods needed to bring it more up to date. Not interested in making it something its not..... just want it to run and ride as well as it can. Thanks in advance.

does anybody have info about how the damper assembly goes together on these forks as at the moment its just a box of bits.

Would appreciate Steve Bisby dropping me a mail - iemery at sky dot com - issues with my Gripper I could do with advice on, thanks, Ian Rode against you many years ago in a Falcon trail, me on my 350, on your 250 , you beat me…...

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

I have just bought a Mikuni carb for my 250 Ossa Gripper. I hadn't realised that the air filter side is 44 mm dia compared to 52 mm dia on the Amal and therefore the standard airfilter won't fit. I do have the ability to make up a spacer ring but I was wondering whether there was an 'off the shelf' solution - hoping someone might be able to help,

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?

Anyone tried one? If so I would love to hear your thoughts. Cheers Jon

This seems good value http://www.offroadmart.com/category/305/PETROL-TRIALS-BIKES-FOR-SALE/listings/934/OSSA-TR280-2012.html is there anything to worry about with a 2012?

My 2011 tr280i is an awesome bike.The only negatve thing about it is it's reluctance to start as easily as other brands are.It's a lot better with the 9v kit and the proper mapping and tuning,but it's still not as good as it could be imho. Has anyone ever entertained the idea of putting another base gasket in it to lower compression? (i know it would be a lot of work and another tuning session) The motor has power that a world class rider is capable of using.I don't fill those shoes.

My OSSA 280i is close to 100 hours up after two years, which is not high usage. I change the oil religiously and keep the bike in primo order but I do notice that there's a very weird low rumbly whine coming from the left side of the crankcase when under load in taller gears. This is disconcerting and I'd like to know if its fixable? It is not present all the time but most noticeable when the torque is loaded, perhaps its the lower e=rev range which enables me to hear it, or perhaps it disappears at higher revs, Any thoughts?

Here's a question for those who understand port timing - which I don't Having a few problems with gear selection set up on my '75 310 MAR. Under the bench is another 310 engine I picked up about 25 years ago. It's a later engine from a green bike. I stripped it to compare selector mechanism and set up but whilst apart I thought I'd compare porting as I'd heard that the later bikes were different. On the 75 bike, the inlet port measures 25mm top to bottom and is 25mm high in the barrel (from bottom of liner to bottom of port) On the 79 bike, the inlet port measures 20mm top to bottom and is 30mm high in the barrel On the 79 bike the port is also narrower in width but I…

Does anyone know the correct torque settings for the upper and lower triple clamp bolts? The Owners Manual doesn't seem to specify them?

It died as tho i had my hand on the kill switch running in 3rd gear.Disconnected the kill switch,still no spark with new plug attached.Any ideas or known issues before i take it to Ossa Canada?