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About pmk

  • Rank
    Advanced Member

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  • Bike
    OSSA MAR & SY250R

Profile Information

  • Location
    Florida, USA
  • Gender
  1. OSSA fibre glass tanks.

    Typically, the resin used is Vinylester. Here in Florida, where boats are common, this resin is easily obtained locally and the cost is not expensive. Currently, I am helping my buddy repair two oem MAR tanks. He has been doing the sanding, and I have been doing and teaching him the glass work. When he returns to Florida this Fall we will finish them. No plans to coat them, but one maybe both were coated previously. To find the leaks, I used a bicycle pump on the tanks vent and sealed the cap with a section of flat rubber. Submerged in a bucket of water, I added a couple PSI slowly with the bike tire pump. As for the aluminum tanks, my buddies MAR currently has one of the Spanish aluminum tanks on it. He bought it new, and from day one it had a leak. Not bad, but it was on the upper seam. He rode it this way a while and just recently had it repaired. Our welder guy is a certified aerospace welder. Even when super cleaned, he commented that the aluminum is a bitch to weld as the original welding was kind of dirty. Ultimately, this aluminum tank was welded with the beads left and not sanded. Plan is to mirror polish it and hopefully not dent it.
  2. Gripper timing

    Interesting, but are you certain retarded timing causes backwards running. I was always led to understand if the timing is too advanced, the engine kick back and provided the kickstart is not engaged, this is the initial engine firing that sets in motion the backwards direction. After that, the timing is firing after top center, and look out when you let the clutch out.
  3. Show Me Your Twin Shocker!

    Photo did not post. Was this the orange bike in Missouri, USA.
  4. Sy cylinder head removel

    Until filled to the top, then the excess will purge out the radiator cap.
  5. Sy cylinder head removel

    Try the Fowlers website for the TYZ, that's your best bet. I assume you are referring to the letter code. Most times, if it is the first piston swap use a B, but they may go as high as D.
  6. Sy cylinder head removel

    Thought you were selling the bike. Seemed like it was sorted out, what happened.
  7. Air/Idle Control Problems

    I agree with FeetUpFun, make certain the carb is clean. These bikes do not like any debris in the carb or jets. Next, ensure the throttle and cable are rigged correctly with a small bit of freeplay in the grip with throttle closed. I will add, my own SY recently had some weird stuff happening. Turned out to be the rubber disc in the choke plunger had fallen out of the brass plunger. Not lost, but would randomly reposition itself, the bike ran pretty good, but would die on any descent.
  8. Sy cylinder head removel

    Reading posts here on TC, I was under the impression that one of the mods done to these bikes was replacing the cylinder studs that secure the head with bolts. This was done so the cylinder head could be removed with the engine in the chassis.
  9. Silencer repack

    I have been looking for it, just no luck yet.
  10. Silencer repack

    Somewhere on the internet, there is a set of photos about accomplishing this. I thought they were linked on the laptop but apparently not. I searched quickly with no luck. I think the guy is from Italy that did the repack.
  11. MAJESTY questions

    Always liked the looks of those bikes. Never seen one in person and not even sure if many made it to the USA. How do they compare to the production bikes of the same ERA, such as the TY and MAR, plus more.
  12. Best Levers

    Agree, the OSSA requires the cable be cleaned and lubed constantly, and typically. Most times this is done the day before an event.
  13. Best Levers

    If it matters, my friend uses these on his 72 OSSA MAR. Forget his setup, but thought he used the hot start to activate his compression release, with it on the clutch side. Pretty certain, after he stalled and could not refire the motor on a downhill, I think he listened and moved the compression release to the brake side. None the less, he runs these levers. My OSSA uses the oem Amal levers, not endorsing them, just saying. https://msracing.com/hard-parts/controls/levers-and-perches/aof-clutch-lever-assembly.html
  14. Compression Release

    No changes made yet. Thought this was interesting. Was asked to inspect cylinders of a friends RD Yamaha. Cylinders inspected good, but has a drilled hole above the exhaust port. Photo later after I resize it.
  15. Ossa gripper engine

    Your photos are accurate. Yes, it appears the split lockwasher has failed and broken into two halves. You should take the extra effort to replace the seal. My MAR had the original seals in it, and they slid out with little more than finger pressure. On these OSSA engines, what is confusing is that what appears to be a washer is not. The entire spline comes off the crankshaft. Most modern bikes have the spline machined as part of the crankshaft. The puller is reasonably priced and must be used to remove the short spline adapter shaft. From the washer as you call it to the top of the spline will come off.