I am confused on the connection rods and piston options for a 1972 DT2 250... Is there anyone out there that is will to spend some time talking about the options ?

Are you looking for help on the actual mechanics side, or possible inconsistencies in the online parts manuals?

I'll kick things off but i'm guessing a bit. Ebay link says for the model with 25mm pin. But think your will have 24mm But early 250's use a cage/roller assembly with fatter rollers which ends up fitting the same rod--if that makes sense. So i guess if you bought this then you will still need the smaller pin & rollers plus thrust washers.
Ebay link won't work--i'll keep trying.
www.partzilla.com/catalog/yamaha/motorcy...972/dt2/crank-piston

eBay item number:
154442447662
Just copy this ebay number. I don't know why linking it doesn't work--i give up lol.
Number gives you a small sample pic then hit it & it opens up a long story on the 431 rod.


 

Is yours 130mm centre to centre

I am looking for a piston kit for my 1972 DT2 250  Engine number DT1-F133299 reed valve engine. The stock bore & stroke is 70mm x 64mm  I have a couple of spare jugs but they need to be bored.  I have a couple of options, One jug can be bored out to 71mm and the other can be bored to 71.5mm, After tons of time calling and searching I am unable to find a pistons kit that meets my needs of the 71mm & 71.5mm reed vakve dyke ring piston kit. 
Has anyone else ran into this problem and if so what did you do to resole the problem?

I also have a good crankshaft with a # 214 360cc connecting rod that is 5mm longer than the stock #311 250 rod, are there any options to using that rod with a mx piston kit ?  

Thank you 

If you're completely stuck could you make a base plate to lift the cylinder 5mm. I/ve done similar on my DT1 piston port motor but that's due to running a 360 70mm stroke crank--6mm increase stroke which was probably a 5mm plate & gasket either side to make 6mm. Anyway that's another story from long ago.

I have a good 311 rod so that's not the big problem, my major set back is not being able to locate a 71 or 71.5mm reed valve / dyke ring piston set... If there was a piston that would work withe the 214 rod I would switch the rods. Just trying to find a piston kit 
Thanks for the reply 

I believe the YZ250A piston ran with the 214 rod. Piston pin height to match that rod. I think Wiseco #398 would work. I bought a #398 and the pin height was to match the 214 rod - only problem is I am going from memory so it would be best to confirm this. Also maybe the Wiseco #230 is also the same - I have this in my notes but can't confirm this.

Dykes top ring isn't important. There will be plenty of 71.5 aftermarket kits for YZ's from the early years but need to know the pin height to top of the piston & they mostly don't list 'that' measurement. I'm guessing the likes of DT250 up to "79 would work & YZ's in the mid "70's. Just google Yamaha 71.5 piston kits bit weed out the two strokes from 4 strokes. Hopefully them that know will be along before i lead you astray. Did like my DT2 though, back in "72.

Have you reached out to Enduronut for a piston/rings?  He often has them.