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About djr

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  • Bike
    ossa 250 mar

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  • Location
    southern england

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  1. 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
  2. djr

    Pre-mix Ratios

    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
  3. 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 ?
  4. There is this tank on ebay at moment is it the same ?
  5. Have you tried boiling water from a kettle ? { be careful }
  6. 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
  7. djr

    OSSA MAR oil leak

    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
  8. djr

    Villiers & Mikuni

    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
  9. 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
  10. Hello, in the past I have had a clutch basket welded to repair the same problem you have , BUT like any repair of this type success will depend on the skill of the welder & the material being welded , you have nothing to lose trying. I have also owned a bike for many months with no Clutch issues , and only found the clutch basket broken after removing the clutch cover to change the kickstart oil seal. There was one finger missing, but the clutch was working fine, and I expect the previous owner just took the cover off , removed the broken piece to eliminate the rattle it would have made and reassembled everything hoping it would work okay. Not recommending you do this , but if its the only thing stopping you riding the bike, maybe you could try this and carry on looking for a basket in the mean time You could try - cmsnl.com for a new part , {if they have one they are rarely cheap} or just use their website to get a part number to google
  11. djr

    Fibreglass Fuel Tanks

    Good points about the problems you may have with modern fuel in a Fibreglass tank { or a plastic one }, using an alloy tank has to be preferable to avoid any problems going back to the original question about fibreglass tanks being banned {for road use} - I think the law was that a tank had to be metal , so this obviously excluded fibreglass & plastic of any kind, but I don't think this law lasted long as I know some BSA road bikes had fibreglass tanks in the late 1960s , and There are some 1980s road bikes with plastic tanks , it must have been a short lived 1970s law that got removed
  12. djr

    Fibreglass Fuel Tanks

    I am reasonably sure you are okay these days with a Fibre glass tank being used on the road As far as i can recall , there was a law requiring metal petrol tanks in the 1970s / 1980s ? But that law has been removed a long time ago I could be wrong , and if I am then someone will surely correct me - but there are plenty of modern cars & modern Enduro / Trials bikes that are road legal , with plastic tanks
  13. It should get easier ,with each nipple you remove the other spokes should get looser , which might mean you can get more room to get some grips on them and crush them / turn them I was lucky, on mine as they had all mostly turned to white powder - not much Aluminium left
  14. If they are the same as on my Ossa MAR, then they are 3.5mm. On my bike the stainless spokes on both wheels were perfect , but the Alloy nipples were corroded and nobody seems to sell nipples in the size required I was reluctant to buy 2 x sets of stainless spokes { at £80 a wheel } I managed to find somewhere that sold nickel plated brass nipples of the right dimensions at a reasonable price , with just a pilot hole. then I got a 3.5mm thread tap and threaded all 72 nipples { yes this was tedious , but the money saved payed for some other parts } I cant remember where I got the nipples , it may have even been a cycle place ?
  15. IF the process of - having a referendum - then negotiating a leaving UK deal - then negotiating a joining EU deal , is as slow and long winded as Brexit was , then don't worry , we can all ride the SSDT for many more years
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