Cylinder ID numbers

I wondering what the ID numbers on the 650sx cylinders are? Not the letter "A", "B", and so on. What are the numbers like the ones on the 750 cylinders? Like a "No stamp, "22" and so on?
Mine have the "A" stock bore, but it also has "11/1", "E-1, and D-(circle 3)? I'm pretty sure the 11/1 is a date stamp?
 
Some 650 cylinders like the ones in the TS have threaded holes for the remote fuel pump to bolt to. Black motors are 86 thru 90. Silver motors are 91 thru 95. All 650s are 76mm standard bore. Silver motors Come with bigger carb and more compression. Not sure about different porting.
 
You might have better luck asking at pwctoday. Not a lot of guys into 650's in general but there are more there than here. I *think* all 650 cylinders have the same porting. I have heard that there is an overall height difference between the black and silver cylinders so the silver have slightly higher compression and tighter squish but I DO NOT know if that is actually true have not checked. All 650,s are very mild motors in stock form.
 

WFO Speedracer

A lifetime ban is like a lifetime warranty !
Location
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As far as I know there are no differences in port heights on 650 cylinders , there are however different cylinders as the 28 mm Kehin carb TS 650 had four lugs cast into the side of the cylinder for the fuel pump to mount to necessitating a different part number for the cylinder. There are also different part numbers for black and silver cylinders . As far as the 88 cylinder goes , no idea that one is a mystery and they only used that part number in 88 .

86 ,87, 89 & 90 650sx and X2 cylinder 11005-3708 ( black cylinder )
88 650SX and X2 11005-3702 (no idea on this one )
89 ts 650 CYLINDER 11005-3707 ( cylinder mounted fuel pump )
91 - 94 CYLINDER 11005-3715 (color change from black to silver )
 
Thanks, the only difference that I could find was the carbs and of course the colors, but the last of the X2's was a 57hp compared to all the earlier versions were 52hp. And that was it. I was just curious. I have a ported 650sx/550sx and a PJS 4mm on the way now.
 

WFO Speedracer

A lifetime ban is like a lifetime warranty !
Location
Alabama
The biggest difference in the 650's is in the carb and the exhaust , on the skis with 28mm carbs the exhaust manifold has no diverter and a smaller opening at the pipe, same on the exhaust opening on the head pipe is smaller, also some of the later models have larger exhaust hoses 2 inches versus 1 7/8 ' . the skis with the 38 carb have diverter manifolds, bigger openings in the manifold and head pipe , more flow, more power.

Basically it's a matched set , small carb , small manifold opening , smaller head pipe, smaller exhaust hoses , this is why some people don't have good luck bolting on a 44 Mikuni carb , the exhaust is too restrictive to make good power , change the head pipe and manifold and it a whole different ball game.
 
While not an answer to your question, if you're looking for upgrade ideas to that 650sx motor there are a few here that have worked out fairly well...

 
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