Yamagodden Posted April 10, 2020 Report Share Posted April 10, 2020 Hi all just been looking at this ty250 I have , do you think this has been sleeved down??? Quote Link to comment Share on other sites More sharing options...
feetupfun Posted April 10, 2020 Report Share Posted April 10, 2020 If you look where the sleeve meets the aluminium casting at the transfer ports you may be able to see if the sleeve has ever been replaced. This is because on Yamahas the aluminium part is cast around the sleeve but when it gets resleeved the old sleeve is completely machined away and the new sleeve is inserted. What is it about the cylinder that makes you think that it once had a sleeve for an 80mm piston? Quote Link to comment Share on other sites More sharing options...
Yamagodden Posted April 10, 2020 Author Report Share Posted April 10, 2020 I took my bike to mick Andrew's and sam brownlee, mick asked if it was 80 mm bore , I had had the head off before and new it was 70mm. They told me about the barrels that jonh shirt did and said you might see this as a thin ring. Quote Link to comment Share on other sites More sharing options...
Yamagodden Posted April 11, 2020 Author Report Share Posted April 11, 2020 It says on here the works majesty engine barrel was standard barrel took to 74 mm and a liner back to 70 . This was what I was referring to, Quote Link to comment Share on other sites More sharing options...
feetupfun Posted April 11, 2020 Report Share Posted April 11, 2020 3 hours ago, Yamagodden said: It says on here the works majesty engine barrel was standard barrel took to 74 mm and a liner back to 70 . This was what I was referring to, Where are you seeing that reference? It doesn't sound right Quote Link to comment Share on other sites More sharing options...
Yamagodden Posted April 11, 2020 Author Report Share Posted April 11, 2020 Look on this site under works majesty, ksmith was the writer and owner. This was what mick and sam was explaining to me . It seems it's called a s type barrel. Quote Link to comment Share on other sites More sharing options...
feetupfun Posted April 12, 2020 Report Share Posted April 12, 2020 On 4/11/2020 at 6:41 PM, Yamagodden said: Look on this site under works majesty, ksmith was the writer and owner. This was what mick and sam was explaining to me . It seems it's called a s type barrel. I found it. This is taken from a 2014 post by ksmith Yes this 250cc OW10 engine was from the 1973 cantilever bike, but it is worth pointing out that all other Yamaha Works Trials bikes ( what ever the model ) had there engines numbered OW10, they are all are very different, ( O= prototype W= works and the 10 denotes TY). note the clutch case and clutch cable on Mick Andrews OW10 cantilever bike below. About ten (250cc) engines were made for the cantilever bike but only a few have survived, at a glance they look like TY twinshock engine`s but none of the components are interchangeable they are one off`s. The barrel is the Majesty S type only used on the Majesty Works bike`s it is a TY barrel bored to 74 mm and re`sleeved with new port timing, the finished bore is 70 mm ID with a stroke of 63 mm. Please see the photos below. Many thanks to Mr Clay Seltzer (vintageworksbikes.com) and Mr Torsten Hallman (four times World MX Champion) for explaining the meaning of Yamaha works numbers. Quote Link to comment Share on other sites More sharing options...
feetupfun Posted April 12, 2020 Report Share Posted April 12, 2020 Can't tell from your photo if yours has been resleeved. Be aware when you resleeve a motor the sleeve usually has a shoulder at the top to stop the sleeve moving downwards through the cylinder, so if you are going to measure the OD of the sleeve, measure it at the bottom end. Quote Link to comment Share on other sites More sharing options...
Yamagodden Posted April 12, 2020 Author Report Share Posted April 12, 2020 It was because mick and sam said about the sleeve and how to spot it, ie no mention off stepped sleeve and the reading of above artical of a 2mm wall thickness sleeve. You can see the sleeve on the bottom of the works barrel clearly, I just did not want to pull my engine down yet to inspect further. 1 Quote Link to comment Share on other sites More sharing options...
Yamagodden Posted April 25, 2020 Author Report Share Posted April 25, 2020 Just spoke to mick about the barrel, he said sam could not remember if one was fitted to my bike and sam would have to inspect the barrel to see. It would seem they only did about 6 of these barrels due to expense!! Quote Link to comment Share on other sites More sharing options...
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