OSSA

Hi all, having some issues with my 250 gripper in the gearbox department. The problem is a loud cracking noise from within the crankcases and temporary loss of drive for a split second.This only happens when the motor is under load (climbing a hill) there are no problems when the bike is on the flat. Originally thought it might be the cush drive but that is all working perfectly. Any advice gladly accepted thanks Higgo.

Are the OSSA spokes the same as any other make of bike ? Otherwise where is the cheapest place to get spokes and nipples ?

My uncle has a 2011 ossa 280, the clutch is very heavy and really spoils the bike, i previously had the same year bike and mine was lovely and light, same as other bikes. Is there a way of lightening it, maybe removing a couple of springs?

After putting a new top end on my 2011,i had it setup at my local dealer.It ran great and started with 3 kicks cold and one when warm.During the setup and for a while after i ran 140/1.Being a bit nervous about the expensive new topend,i changed to 100/1.After a while it got tougher to start when warm.When cold it would start 1st kick,but needed 3 or 4 when hot. Changed back to 130/1 and it's back to 3 when cold and 1 when hot.No idea that this technology was so sensitive. Just an fyi for others.

Over the weekend the kick starter on my MAR shot craps and quit working. Pull the side cover off, kick start spring is intact and the shaft rotates freely. No metal in the oil. Just isn't making connection to turn the motor over. Thoughts? Can it be repaired without splitting the cases?

Hi Been having some issues with the mixture on mine, plug is always sooty black, went through new plug in a trials and a practice today, saw that the TPS was loose too, anyone know of somone in the leicester area that can reset the tps and have a fiddle with the mixture? i have had a google but couldnt see any trials mechanics in leicester at all but them i am not the best at googling. I do plod around on the easy routes so i dont make the bike work as hard as it could, i cleared it out with a quick 4th gear full throttle blast and it smoked like hell for a while. that did make it a little happier but then wouldnt idle, cleaned the plug and its all lovely aga…

can only find lower ones for sale is top the same ,are they a special or can you get them of shelf

Looking towards the winter, as the MAR has a bit of a false neutral thing going on: Who in the UK is the expert at engine teardown and re-build? Can deal with most of it but bit daunted by the shimming of gears etc as above. Thanks

Hi, In the final stages of rebuilding my MAR and need some advice on magneto's. It is road registered however it only has the 3 wire ignition only magneto. Previously there was just a battery for the lights mounted on a homemade side panel. I am wanting to keep it original so had to do away with the battery. I have been looking for a magneto/alternator all over for a few weeks now with no success. Can anyone help and point me in the right direction? Pic attached to share Thanks Mark

Hi again. Got part throttle fluffyness on 75 MAR250. Amal carb. Had it apart, done all needle heights, all possible air screw combinations, never right. Air screw fully in gives nice no throttle type torque. At full throttle all OK, just on part futtt splutter. Never stalls, always starts first time. No air leaks, although compression when kick starting seems a little easy. 50 to 1 synthetic. Thinking of a Mikuni carb from Inmotion. Any input appreciated. Thanks

Hi, got a nice MAR here, gears on right. I can see that the swap of the gear lever is simple. Any parts needed to put brake on right? Also appears to have two neutrals, one between 3 and 4 as well??? Many thanks

Just a curious question regarding shock mounting point size, I have just got hold of this project and just going over it to see what's what, and noticed the hangers for the shocks are quite big 15mm it's been powder coated by previous owner and looks like a collar has been left on all the mounts? Can anyone tell me what size they should be before curiosity gets the better of me

I recently got my first classic bike, from a friend who just wanted it out the garage. He has said its a ossa mar 250 mick andrews rep. I don't know enough about it, to know for sure if it is what it is claimed to be. Any help and advice much appreciated. Earl

Hi, can any Ossa experts shed some light on an easy way to remove rear wheel? i've done it but its a right pain. If you had to do it in the field it would be a right aggro!! Is there a mod or technique to use? By the way got it starting ace now with 12v li ion rechargeable battery now with switch on bars, result!! Ian

The story of this OSSA is posted up in introductions...I am in the process of bringing this back to life. Unfortunately gas was left in the tank for a very long time and when I pulled the Amal 627 off to rebuild it was filled with goo...I'm assuming resin from the Fiberglass tank? I cleaned everything in a dip type carb cleaner and it looked pretty good. I put it all back together and using an auxiliary fuel tank I turned the petcock on tickled the carb and gave it a few kicks. Nothing. I gave it a quick shot of starting fluid and she fired up but bogs badly when I roll the throttle on. It seems like it wants to run on full throttle but bogs from partial to mid throt…

Hi there current OSSA Owners. I'm struggling with the decision to buy a little OSSA explorer...I test drove it, loved it, but have been advised by many against buying an OSSA. I'm trying to figure out how much of the negativity (i.e chews through gear box) is still lagging from the 2011/2012 issues and if folks that own newer (2013/2014) bikes still have problems. Truth is, if OSSA was still in business, I would possible even buy it with the transmission issue, I though it was one of the smoothest powered trials moto's I have been on (owned a Gas Gas 300, named the devil, a beta Rev 3 2003 and we also have a 2015 beta evo 200)....a bit difficult to start when …

Anyone have to replace the little rubber stopper for the kickstart? Any tips to give me while i install the new bit?

Hi could someone please tell me what the shock length is on a mkii Mar please. And also apart from price what advantage is there to putting a flat sprocket on the rear with the spacer? Does it help prevent the spindle from bending Many thanks

I have an Amal carburettor with the number 627 cast into it and 429 stamped into it. Is this the standard mar carburettor? The main jet is a 140 and the needle jet is a 106. Are these somewhere near correct? My new (to me) mar has apparently come from Italy if that might make a difference

I haven't attempted to remove it yet, but my kick-start is loose, ie. It doesn't stay in the folded position to keep it out of the way during riding. Is there a warn part I can replace / build back up with weld? Or is it a case of throw it away and completely replace?