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Nr1 is one of the 90$ special bought this month  and Nr2 is bought 2 years ago.
1 does have some very low port timings, and funny counterbore on the bottom of cylinder, the liner is thinner 1,5mm per side compared to the 2nd one there (on top looks like its thicker).
Casting looks way better, no casting flashes ect.
The A transfer tunnels doesn't have the hook cast on the exit, just straight shot
Mine came with bent fin and one piston is clearly having hard time to go through the bore. Roughly measuring exh is 32mm from top, transfers except boostport are a lot lower (don't remember exact height).If the sleeve is ok, this might be a good candidate to port it to stock spec. Pistons look better than those that came with nr2 older set. But I would probably look for the TKRJ or something else.

And link to the 2023 set https://www.2strokeworld.net/forum/index.php?topic=5650.msg48758#msg48758

Here's more photos of 2025 and compare to older one. https://imgur.com/a/ne7fs8Y

Great, so that's what I will do for start. Will do update when engine will be running. Thanks for the help.

Thanks for replying.
I disassembled the "bad" carb and needle looks like this , you can't feel any steps but the coating is gone in the "midrange" , also atomizer after installation into the new carb with  mainjet and  the brass spacer/gasket  sits kinda low in the body ? And I forgot to mention that slides in new carb are 2.0 and old ones are 2.5(they would need to be machined to correct length, they are in perfect condition outside   ) .
I could try doing it like this but it don't like wear of  that needle. Would I also need to change(drill and tap passage for jets) the air correction jet for using that old brass in new body? (Air would go straight from the Y boot , not the separate line from airbox) .  I checked and that  stuff for the Dave F mod is available in UK so I could get this here (Poland )  in few weeks I think .

Hi guys, I'm slowly getting my rd250b 75' (euro model ) on road back again and have question about new VM28 carbs.
My original hi top carbs are in very bad condition (previous owners hack jobs....), bike was running poorly and couldn't get it to work right (one carb body does have damaged air screw seat by using hand made jet?? , carb body where needle jet sits is cracked...)   . So I bought new set of Vm28-57 to use it instead of original ones.
They came with 5DP39 needle and  169-n8 needle jet.
Engine is (will be ) stock, except one piece YZ reed petals , reed spacers and K&N YA0700 (couldn't find the original paper one here) .
I know I have to modify them for oil injection that is no problem, and change pilot and main jets ( start with 30 and 150  should be safe) but will that combo (5DP39 needle and  169-n8 needle jet.) work ?? Or I have to look for some other ones? I have found that some guys here are running those new carbs in their bikes, so maybe someone could shed some light on that matter?
Cheers guys.

I have in parts right now  250C from 76 and 250b 75 euro model,  so if You want I can measure splines lenghts ect ect.

http://www.natsforum.net/viewtopic.php?f=9&t=174&start=610#p10523  Here's a thread of 2 into 1 done proper way. You need to look around that thread but he was in contact with the guy that tuned this TZin 70's , maybe he will share some info when he will se some progress of Your build.

http://www.natsforum.net/viewtopic.php?f=9&t=174&p=2974#p2973 about those ebay pipes.