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  1. The piston diameter on my 198B is 73.75 giving a size of 256cc. The underside of the piston is stamped DINAMIN, and although the piston and bore are in good condition I wonder if anybody knows if this was a fairly standard mod just to maximise the capacity rather than being overbored so many times over the years for some strange reason. Also does anybody know what bike would this piston? might have come from? GasGas perhaps?? The InMotion site shows piston sizes up to 73.00 only. Thanks.
  2. Thanks guys for the colour info. It is just I thought the blue shade on the forks and yolks on the 199B models seemed to be different to the blue on the 199A frames.
  3. Does anybody know if the blue colour on the 199A and 199B are the same, or is the 199B a different shade of blue? Especially the blue on the fork sliders and the yolks on the 199B Thanks
  4. midgy

    Fuel cap O'ring

    I have bought O-rings from Simply Bearings. They do very detailed descriptions of the various materials (there seems to be about 7 different types of material) for zillions of O-rings of all shapes and sizes from less than 2mm to 600mm and beyond with details of various chemical resistances. The link is:- Choose Nitrile, Viton, EPDM, O-Rings Seals by chemical resistance and temperatur (simplybearings.co.uk) They do not seem to sell single o-rings but sell usually a pack of 2. Fine for me because I needed 2 for two identical bikes.
  5. midgy

    Rev vs Evo?

    Hi there, I owned a 200 Rev3 but it was sold for a newer 200 Evo. I found the Evo a long time to get used to and even many years on I sometimes wish I still had my Rev3, as I found it to be a really good bike for my age and experience.
  6. Thanks for the comments everybody. The engineer who is doing my hubs is long experienced and highly regarded and knows what he is doing. The liner being pressed in with 2 thou interference fit is of suitable material. My liner has an OD of 129.96mm and an ID of 125mm. The standard chrome lined hub is 125mm ID. The hub assembly with brake shoes fits perfectly within the liner.
  7. Hi, Many thanks for your comprehensive and detailed guidance. I am aware of the risks involved and accept that the liability rests with myself. My man is aware of the risks as well, and hence he was looking for a specific specification which I appreciate is not available. I explained to him that the bike is for trials and not high speed or even road work and the likelihood of the drum heating up and coming loose is minimal. Considering what you have said, I may suggest to my engineering shop man (a one-man enterprise, and with highly regarded expertise with engines etc) to machine the hubs to accept the liner with an 2 thou clearance. ie the liner outside diameter to be 0.002 oversize to the hub for safety. I am not too sure my man would heat the hub in the oven and freeze the liner, but I may do that myself, if I ask him just to ream out the hub to the 0.002 thou below the liner OD. Then I could tap the liner into place myself. I may also consider using a resin as well to take up any irregularities within the reamed out hub, I appreciate your assistance and will let you know how I get on. Regards Ian
  8. Hi Guys, My local engineering company who are to ream out and then press in the steel liner into my back and front hubs has been asking what the interference fit should be. Too small and the hub might crack. Too large and the liner may come loose. My man thought it might be either 4, 6 or 8 thousands of inch. He is reluctant to take it on unless he has the correct spec that works. Any guidance appreciated. Thanks
  9. Hi Thanks for the info. I have done it before a long time ago, and I will likely try it again. I have taken all the off set measurements and will give it a go, once I get the hubs back from getting a cast iron insert fitted to improve the brakes.
  10. Hi Guys, I need to get my Sherpa 199A wheels respoked. Anybody any ideas of a wheel builder near Glasgow or central Scotland?. Thanks
  11. In reply to Richard Sawatzki about a pair of NDB776 car brake discs, what car are they from?
  12. Hi Bully, Thanks for your comment. My other 199A has a pre-drilled and tapped hole for a decompressor (now fitted), but came with a screw-in blanking plug which I think was original equipment in 1979. I think I will get a local engineering shop to drill and tap the central part where the spark plug should be and install a decompressor and a spark plug in the other two holes. I will likely have to live with the probable Pursang head and hope it runs ok. (I have not yet run the engine)
  13. Hi guys, I Have recently acquired a 199A. The cylinder head has two spark plug tapped and drilled holes, one pointing towards front and one pointing to the rear. The usual central spark plug hole has not been drilled or tapped. This is different to an earlier 199A I owned. The combustion chamber is also a completely different shape to my earlier model. Has anybody any ideas why this is the case? Perhaps the head is off a Pursang for some reason? The barrel is stamped 199A so that seems correct. Thanks.
  14. Hello Wonder Boy, I used Philpots in Bedfordshire to rechrome my Beta Rev 3 fork stanchions after reading an article in a Classic bike magazine. The magazine explained the processes and what they can do to refurbish fork legs. Very good service and a very good price. The results were excellent and I reckon the refurbished fork legs were better than the original finish. I have attached the link below for Philpots. They are meant to be the best in the business and I would tend to agree. Recommended. http://www.pittedforks.co.uk/index.php
  15. Many thanks, Carl. I have a parts manual and the one marked VAR 41-52 will fit a 199A, however I have now ordered the kit from Powerdynamo in Germany which has the flywheel and rotor all within the kit. I appreciate you getting in touch
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