April 2, 201016 yr Does anybody know if genuine Yamaha pistons are still available for a twinshock TY250?. I've got hold of a 'pattern' piston from a UK Yam spares dealer and it's been nothing but trouble .........any help would be appreciated.
April 2, 201016 yr Marky , your best bet is to talk to nigel birkett, a mind full of yamaha info, good bloke too
April 2, 201016 yr Author Trying to catch him in Pitley, tried loads of times and no one answers the phone......must try again I guess.
April 2, 201016 yr Trying to catch him in Pitley, tried loads of times and no one answers the phone......must try again I guess. Funny that I tried him on and off recently for parts for the Scorpa and all I got was engaged tone all the time ??
April 2, 201016 yr I guy's , took my 250A out from the basement today, It started right up but it seem that it only want to run with the choke on, maybe the float is not well ajusted will check that tomorow. First trial comp off the season sunday ( first in 30 some years ) I hope I will have the problem fixed. What happend when you put a DT piston in a TY 250 A? Has anybody tried? Guy
April 3, 201016 yr Does anybody know if genuine Yamaha pistons are still available for a twinshock TY250?.I've got hold of a 'pattern' piston from a UK Yam spares dealer and it's been nothing but trouble .........any help would be appreciated. I think the pattern pistons available are actually DT. I had one and it was too long, the skirts needed shortening as they hit the crank at the bottom of the stroke. Crap quality too, rattled within minutes, new piston/bore. Birketts are just very busy so you have to keep trying. I've ordered two or three times over the last few weeks and it's come next day. Or try the US, or ebay USA for new old stock. There are also a couple of vintage Yam specialists who used to advertise in the back of TMX.
April 3, 201016 yr Author Cheers dave, will keep on trying. Funny you should mention the piston length, I noticed the piston was very very close to the crank when I was trying to get the barrel over. I've gone down the 270 route with my mono (wished I had not of bothered now)...i thought i was buying OE yam stuff but when the piston came it was some american thing, the guy whom i bought it off said he was awaiting the rings, I went ahead and got the barrel rebored to suit the piston. When the rings came they were pattern too and did not fit the piston properly, had some 'genuine' rings sent out but there no good either...all i can put it down to is the pattern piston is crap. All sent to try us I guess.
April 3, 201016 yr Genuine OEM pistons, rings, gudgeon pin and clips all available up to 4th oversize from Speed & Sport in PA, usually with a good discount. Shipping would be around 20 quid. Tony
April 3, 201016 yr Author Just go to john at trial & Trail he will sort you out he can get gunuine pistons No he can't
April 5, 201016 yr I've used Wiseco DT250 piston kits in the last two TY250 twinshocks I've had rebored (5 years ago and 1 years ago) and they have both been been fine since - they haven't rattled and everything fitted perfectly
April 5, 201016 yr I've used Wiseco DT250 piston kits in the last two TY250 twinshocks I've had rebored (5 years ago and 1 years ago) and they have both been been fine since - they haven't rattled and everything fitted perfectly Yes, Wiseco are a quality piston, unfortunately the pattern pistons sold here are chung-ching rubbish or such-like, no-one sells Wiseco here. Are the Wiseco DT pistons an exact copy of the TY item then? No machining, trimming etc required? What about the slots on the inlet side, are they the same? The pattern pistons I was given were too long and the skirts had to be cut off to stop them hitting the crank (fitting them in a TY twinshock, not the mono) I was told they were probably DT items but I don't know for sure.
April 5, 201016 yr Just to add my two pennarth (if that's a word) I recently bought a + two mm piston for my 175 (now 185 with the big piston) and got it from one of the suggested reputable sources, it was not cheap at
April 5, 201016 yr Author The problem I've got is the top piston ring will not sit flush in the piston when the ring is fully compressed...ie; the ring groove on the piston isn't deep enough, the ring is sitting proud of the piston. Just been in the shed to found the box the piston came in......'Yamaha piston DT-2' and it's made in Japan and distributed by the rocky cycle co, sunnyvale, California. Just measured the pistion to pin and it's the same depth as my old std Yam one so I guess thats ok, it's got the same ports in the back of the piston so all's well there ( I've also had a Wiesco rod fitted ). I'll try Birks again Tuesday.
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