bambam_n_chunx

Thanks for help, the exhaust port is not closed at tdc so I guess I'm returning it and starting the hunt again. Regards the reed valve, there seems to be a plate where this would go and I've read they removed it to soften power. Looking forward to riding this as it's been in bits since it came from Italy

I've managed to source a new piston for my 84 jumbo from Italy, however when it's arrived the skirt is 5 mm shorter than the original. As this will affect the inlet port timing will the bike run or do I need another? The pistons are almost impossible to find.

I`ve just about finished rebuilding my cub, just need to sort the rear shocks and ignition system. I`ve 2 questions What length shocks will I need? Its currently fitted with a capacitor type ignition which seems to be working well, so should I replace it with an electric ignition? Which ignition is best? as there are 2 types, one which bolts straight in and one which needs posts machining onto the crank case. Thanks for any help.

Thanks Woody and everyone else who has helped. Seems i`ve bought a pup, shame really as its a bit different and I like that. I dont think i`ll be going overboard on a refurb.

Is the headstock really that different to standard? https://lh4.googleusercontent.com/-xxBvVjJTaVs/VHH9d42fZsI/AAAAAAAAAII/mD9ZYp0AhqU/s912/100_1958.JPG

Don Morleys book says JR. rode a Johnson modified ossa, there's also a pic of the same bike being ridden by another rider in another book I've seen when JR. went to swm. Can't remember the book or rider. As the bike is 40 yr old it's had things changed, the wheels and tank are certainly not right and I will be trying to put it back to somewhere near original but as regard to value, it doesn't matter for the time being as I've no plans to sell it. I would like to trace its v5 if it had one but that's all. My guess is the person who made the claim knows more about it but would rather keep his info, Thanks for the help.

I thought that but this has no air valve and I thought they all did, also it seems to work ok and if it were meant to be a pair would it be strong enough. I've had an email from someone claiming his dad built it and he would like to buy it back for sentimental reasons but obviously it's not worth a great deal any thoughts on this

Keep it out of sight

I know i`ve probably bored everyone by now but when I removed the tank today I noticed it had what looks like two tank stops on the top tube. I`ve never seen these before and thought it might be a clue as to who made the frame. Any info on the frame or bike would be gratefully received.

There's no reed valve but what looks like a conversion to fit the mk11 Amal carb. I'm yet to ride it as I'm still waiting to get an air box made for it although I've just replaced the swing arm bushes and refitted the sump plate. The fact someone has spent some time tidying it recently is why I thought it might be recognised although the lad I bought it off said it had stood in his garage a long time as he couldn't start it. It does run very well now that I've fitted the missing crank seals and fitted the missing clutch centre nut.

Thats the number stamped on the front right eng mount, theres no prefix on that either so cant be sure its right. It doesnt seem to have been tampered with though. I had a look for its ID on the ossa world site before my last post but thought the same as you on the high number. Frame number is 768**241 which seems wrong to me although i`ve nothing to compare it with. If its an after market frame it could be the original number although if its a converted ossa frame will make it wrong and probably the engine too. Wheres JR when you need him?

Thanks for the replies, I guess its a 244 then, the engine number is 7862** but I guess the frame number is of no importance as it has no B prefix and too many digits. goudrons, I`m still not 100% on who made the frame, I did post it on here when I bought it but was only told it was a holden bike, I thought someone might have recognised it but i`m never that lucky. Im hoping to ride it next year once ive given it a good checking over.

Any ossa fans out there know if theres an easy way to identify the engine size of a 70`s mar. Its been suggested mine may not be a 244 as originally thought but a 310. As the bike is running ok at the moment I dont want to take it apart to find out but I would be interested to know.

Have you checked and cleaned the fuel tap?? If its been stood a while chances are its full of resin. Ive a haynes manual somewhere if you havent and want a read of it.

Thanks for adding them, looking at mine and comparing the two, mine seems to be a bit rougher perhaps a home made conversion? The seat stays are bent backwards and the rear wheel mounts have been cut away so the wheel is easier to remove. Also the back brake is different. Its next on the to do list after my cub project so hopefully once i`ve checked everything over i`ll be able to ride it a bit next year.

Looks like a steve wilson after market swingarm upgrade. I`d leave it in if it where mine.

Having a little trouble identifying this ossa, I`ve seen some pics of other canti-lever bikes but none have the bend in the seat stay above the brake cable stop. I`ts obviously recently had some restoration work and I`m hoping to find out who did the work and hopefully trace its history. I bought it in Leeds and the seats been recovered by dlc so guess its a local bike. I`ve added some pics and with any luck someone might recognise the bike and help with leads. I guess it would have been registered for road use at some point and I`d like to to trace its reg through previous owners etc. i know its a rare bike so would think someone must have seen it about and I`d be grateful for any help at all, just to know some of the bikes history would be good.

New crank seals fitted and clutch back together, now running. Will have it looked at properly whilst airbox is being made but nearly there.

Tried to id the bike on the ossa world site but the frame number starts with a 7 so my guess is it's not a converted frame.

I beleive a few were made in the 70`s but thats all i know. It has a mar engine in, with a fancy exhaust pipe on and air forks. It still has its brackets on the sides where ssdt numbers would have been fitted and the yokes and chain case are neatly carved out. Someones changed the tank for a gripper one and the airbox is missing which is a shame but otherwise its all good. A new airbox will be easy to make and the tank looks better. Will be good when sorted but not sure what class it will be any use for.

Just picked up a 70`s ossa mono from leeds. I remember seeing some pics of JR riding one but cant find any on the web. Does anyone have any pics they can post or email me?

Seems like a step back to me, isnt the whole idea of having works riders to develop next years bikes for us wannabees?

At almost 40 years old and the owner doesn't know anything about it chances are it's only any good for spares or will need fully sorting to be any good in a trial. You have to ask how much and why you want one. If it's to use and you haven't much experience with a spanner I'd buy a good one off someone in the know.

Its been advertised for a few days, if I hadnt been pushed for time i`d have been and bought it. I spoke to the guy who said he wanted £250 then later dropped it to £200 because I found out it was further away than he said. The rear wheel is wrong for the model, looks to be from a much earlier bult.

LOL No ones mentioned the bottom frame rails making it a late 70`s model, they had round tubed swing arms before the gussets were fitted with the alloy sump models. Still a bargain for £200