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96 yz 250 stroker kit and cylinder interchange

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I have just been gifted a 96 yz 250 that has been dismantled and sitting in a shed for 3 years [emoji846] . I can assume almost everything on it will need attention;)... barrel and piston looks to be in bad shape . from what I read , the 96 motor was its weak point with hardly any bottom , powerful but short amount of mid range and no top end . , but everyone loved the 95 .. anyone know what or if any cylinders will interchange and have same Pv setup ? ,,, and there also seems to be a small amount of information on stroking the 96 to give it some bottom end , by using an 88 rod , can anyone remember back to the mid 90s [emoji846].. it’s good to to toying with a Yamaha again , my last one was a 400f when they were taking the world by storm !! [emoji846]

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Changing the rod will not stroke an engine. What you are refering to is a long rod kit. The longer rod has more leverage on the crankshaft. It requires a longer power valve rod ,cylinder spacer, and a second base gasket. I had a long rod kit on my 95YZ and it was the fastest 250 2T I have ever ridden, it made a great woods bike too.

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Ah I see :). Thanks for the info , any ideas where to buy the kit if it’s still available? Or the specs for the spacer plate etc :)
Thanks for the help :)

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Yamaha ran out of the kits years ago. It is still possible to build one. You will need the proper year rod, power valve cover, and a spacer plate can be made by a competent machinist. The timing will have to be adjusted slightly.

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hondaxr650rrrr is spot-on. :prof:

Lots of discussion and threads about the long-rod mod online (and here on TT). When the 1996 YZ250 was introduced, Yamaha racers were scrambling to get the '94-'95 performance out of their '96s, even going so far as to grafting earlier cylinders on. (Look carefully at pictures of the factory race bikes!)

The long-rod kit was pretty much a must-have for the '96 YZ250, and lots of them turn up on used bikes.

The rod used is from various Yam 250's from 1983 to 1989. It's 5.0mm longer, part number 24Y-11651-01-00.

There was a place in Australia that had their own long-rod kit, but I wasn't able to find their website this time. :excuseme:

The Yamaha kit is part number GYT-4MX03-00-00. Though no longer available, if you could find a listing of the parts in the kit (and part numbers!) that could get you on the right path. 👍

Matt Crown here in Michigan was well-versed in the long-rod kit. (His kitted '96 YZ led the first lap at a National moto!) He cobbled one together for my '96 (including a laser-cut spacer plate), but that was many years ago. It may still be worth looking him up.

Good luck, and keep us posted with what you do. 👍

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Thanks so much for the info guys :) I didn’t realise it was a kit direct from Yamaha !!! I thought it was aftermarket company , I’ll start with those part numbers and see what I come up
With , I’ll keep this post updated
This site is great !!
Thanks again folks :)

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Just an update on this built guys ... rod , pin and bearing are all still available from Yamaha... the power valve parts are discontinued but I managed to source from a wrecker ,, all the gytr stuff I will have to get made up , but should be easy for local engineering shop .
But Typically im getting ahead of myself, im half way through a 85 cr 250 restore too . But I’ll keep gathering parts for the yz ;)
Thanks again for everyone’s input , I’m exited to build and ride this yz :)

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