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Post by philip on Dec 7, 2019 8:00:52 GMT 1
About to rebore the cylinders, should I fit the usual LC pistons or move to the YPVS pistons? Would it make much difference and are there are modifications required to the piston or cylinder
Thanks
Philip
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Post by jon on Dec 7, 2019 8:40:26 GMT 1
Tang debate?
Jon
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Post by reedpete on Dec 7, 2019 9:38:54 GMT 1
Tang or Tango, that is the question. Not sure even Aristotle would have that one sorted.
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Post by reedpete on Dec 7, 2019 9:46:42 GMT 1
About to rebore the cylinders, should I fit the usual LC pistons or move to the YPVS pistons? Would it make much difference and are there are modifications required to the piston or cylinder Thanks Philip Philip, you probably wonder why not strait answer... basically there are plenty of 4L0 style pistons out there to choose from so don’t worry too much. YPVS will also fit. There is no significant (any) change to the performance but there is a hot debate as to wether a small feature on the bottom of the piston should be removed. It serves no purpose on a 4L0 as the inlet doesn’t have a bridge, and if the engine is tight to spec , has given no problem to many. However from first principles of how a piston skirt should be profiled to pass a port it causes concern for some. There is some evidence on slack bores that it can cause an avoidable blow up. Best choices of 4L0 aftermarket are Mitaka, IMD or gen yam if you happen to find some. So YPVS style is second choice on a standard engine. On a tuned 4L0, there’s a good argument to run a YPVS piston and then it’s just about wether to leave or remove the tang..
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Post by philip on Dec 10, 2019 11:30:18 GMT 1
Thank you for the infor, very much appreciated upon checking on E Bay for some reasons the YPVS pistons appear to be much cheaper than the LC Pistons
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Post by reedpete on Dec 10, 2019 12:54:15 GMT 1
Thank you for the infor, very much appreciated upon checking on E Bay for some reasons the YPVS pistons appear to be much cheaper than the LC Pistons Demand is higher and therefore competition is stronger, prices naturally lower. Lower prices drive traffic away from 4L0 and toward YPVS , exacerbating the situation. An interesting point I didn’t make before is what yamaha ‘say’... generally if parts on newer models can be used in older applications then the part numbers will be superceeded. Many examples of that on the LC, some not appreciated when you get function equivalents but cosmetic difference ...so evidence yamaha will do what’s best for themselves when it suits them. anyway, yamaha do not list the 31K piston as a superceeded part for 4L0...... Personally I have no hesitation to run ypvs piston in a 4L0 but I remove the tangs ( been cutting bits off the piston skirt since day dot so doesn’t phase me). If I wasn’t allowed or didn’t want to tamper though, I would use the 4L0 piston.
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Post by mannanan on Dec 10, 2019 13:26:04 GMT 1
Not wishing to reignite the great piston debate so no comment from me on tangs. All I would say is I am seeing the different pistons for both models available at the same price from PJME. Mitakas at £45 each and Woosners at £92 each so unless I am missing something, I don’t see an issue here.
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Post by Tobyjugs on Dec 10, 2019 13:49:40 GMT 1
Not wishing to reignite the great piston debate so no comment from me on tangs. All I would say is I am seeing the different pistons for both models available at the same price from PJME. Mitakas at £45 each and Woosners at £92 each so unless I am missing something, I don’t see an issue here. That's quite some difference in price between the two. I deliberately choose Prox pistons for Kees's engine the last time because they were cheap.
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Post by chippy348 on Dec 10, 2019 14:44:03 GMT 1
Thank you for the infor, very much appreciated upon checking on E Bay for some reasons the YPVS pistons appear to be much cheaper than the LC Pistons What brand of piston are you looking at on Ebay? and are you looking at Ebay UK
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Post by Tobyjugs on Dec 10, 2019 15:25:03 GMT 1
Thank you for the infor, very much appreciated upon checking on E Bay for some reasons the YPVS pistons appear to be much cheaper than the LC Pistons What brand of piston are you looking at on Ebay? and are you looking at Ebay UK Chippy have you got a favourite brand of piston? If yes what are your reasons for it?
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Post by chippy348 on Dec 10, 2019 16:36:11 GMT 1
What brand of piston are you looking at on Ebay? and are you looking at Ebay UK Chippy have you got a favourite brand of piston? If yes what are your reasons for it? Made in Japan Mitaka pistons, i have to stress the made in Japan Mitaka ones and not the made in Taiwan ones you can get either under the "Aoki" brand or Mitaka. I have been selling, fitting and more importantly using them for nearly 30 years. In Road,Race and endurance conditions never had any issues. As a bit of a back story it was me who pushed for a dedicated 350LC piston to be made rather than the "fits all" YPVS piston, customers wanted the correct looking piston and also the whole "tang" debate.
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