djr

Thank you for thinking of the non facebook users ( yes , there are millions of us who haven't been brainwashed into believing facebook is the only possible way to communicate)

Yes . I do know the secondary voltage on my 2 stroke , but I am sure the ignition hasn't enough power to do welding. ( which has been quoted for the electric bike concerned in this post ) Thanks, I will take my chances with the kill button

Wow , I think I will be sticking with 2 stroke power , all this talk of - 50+volts , 800A fuses, mixed with heavy rain , is not convincing me that electric is the future. Good luck, I hope its a simple fix

Never been interested in Pre65 trials, because 90% of people involved seem to love moaning about what other people are doing and taking everything too seriously. I do think it would be better if the bikes at least looked like an old bike - tank shape , seat, frame , colours etc. instead of looking like a modern bike with an old engine fitted, but thats just my opinion as an outsider and its now too late to expect the riders who have spent £thousands to change their machines I ride a tatty Ossa in non serious trials , where many people have better machines than me, but I just enjoy my own riding and dont moan about what other people have got. If someone is rich and wants to spend £1000+ on a pair of forks , then good luck to them. there is a place for everyone , most trials have an easy route that any original bike could get round , you dont have to keep up with the Jones , enjoy doing your own thing. I do think its a fallacy that there are thousands of Original Bikes in sheds with owners who are just waiting for events catering for Original Bikes , there may be a few but the majority of these bikes are either Family Heirlooms , or they are being hoarded as an investment

I seem to remember someone fitting an OKO carb to an RL250 , but cant remember if it was on here or another forum. As it was an RL250 not a beamish , it may have been someone in the USA or Aus , NZ etc. ? A job for Google perhaps ? Failing that you could try your Cota carb on the Beamish as it is and see if it works okay, { they are both 250cc piston port 2 strokes , so similar engines } - if okay then use the same jetting / settings as a starting point and fine tune later

Cheap options would be - lowering compression as mentioned , OR - How about fabricating a longer kick start lever , for more leverage ?

Partly Covid etc. Partly the dreaded facebook , God knows why people think facebook is easier to access - its no easier to access than any website or forum I find the layout of facebook is crap, any useful info buried in people trying to sell rubbish Anyway, this is a good site, long may it continue

40/1 with a decent modern oil should be okay for trials, if doing any road riding then maybe more oil would be a good idea. I have run my Ossa MAR on this ratio with synthetic oil for years with no problems ( may have just been lucky ) personally wouldn't go any leaner than this, as I think too much oil cannot do as much harm as too little oil could do

sounds like an air leak somewhere crank seals / gaskets etc. what carb have you got fitted ? have you recently worked on the bike before this happened ?

There is this tank on ebay at moment is it the same ?

Have you tried boiling water from a kettle ? { be careful }

Sorry I have no idea what an original unused gasket would measure up to, but I do have a cheap looking aftermarket MAR gasket ( not Vintco) here in blue card that measures .020 inch Your .030 inch gasket will crush down a small amount when assembled & all screws torqued up, but the only way to see how much would be to - 1.assemble - 2. torque up screws 3. - dismantle - 4. measure gasket ( then buy another Vintco gasket to use if you are happy with measurements ) If you say the old gasket AVERAGES -.025 inch , then I wouldn't think you are far off Are the tolerances that fine on an Ossa ? I need to rebuild my own MAR engine soon, and I think I would rather have too much clearance rather than too little - better loose than something binding - I will be looking for a thicker gasket than the one I have

Hello, I have an Ossa MAR and it has always leaked a little from the gear lever shaft - probably because it doesn't have a proper oil seal - I think it has something like a felt washer on the inside and an O ring on the shaft I have renewed these and it still drips now and then There should not be a leak between crankcase halves as this has a gasket , and if your engine has recently been rebuilt with a fresh gasket then it should be oil tight - you also don't want this gasket to leak gearbox oil internally into the crankcase area, or air to leak from the crankcase area - probably the most important gasket on the engine & the hardest to change The only other place I have had a leak is from the gearbox sprocket oil seal { a new seal fixed this }- this could possibly run down underneath the engine If the leak really is between the crankcase halves , and you have paid to have the engine rebuilt - then I think you should have a chat with whoever did it , to confirm what work was done

It always makes me laugh how Pre65 people can rewrite history for Amal concentric carbs , but wouldn't want to allow a genuine 1964 Mikuni carb to be used if you had one

I mix 40-1 full synthetic in my Ossa MAR 250, I did originally use 50-1 , but the bike seems to run better and less hot at 40-1 just my opinion , and you will get people swearing by 80-1, 100-1 etc. as well as ring sealing , the oil can absorb some heat as it passes through the engine , and most importantly - bearing lubrication , some old 2 strokes have bearings that are only just up to the job, so less oil could be the last thing they need