650/X-2 Best carb for 650sx

Location
Corona
OK, thank you for the information that’s really good to know it was one of the only stairs I could find at the time but I’m thinking it’s gonna be my car because I have the stock 28 and I’ve heard it’s a piece of junk I’m going to try and borrow a Friends CDK2 to 34 and see how that works
 

WFO Speedracer

A lifetime ban is like a lifetime warranty !
Location
Alabama
Whatever, 28 carbs are junk and 44 carbs are too much for a 650SX , are there any more people with opinions that don't mean anything in the real world, if so lets hear them.
 
Whatever, 28 carbs are junk and 44 carbs are too much for a 650SX , are there any more people with opinions that don't mean anything in the real world, if so lets hear them.
sbn44 is best for a stock/stock-ish 650 engine. I've just had good luck with dual sbn38s on single intakes with my old builds. All around ease of use the 44 is best bang for the buck.
 
Location
dfw
I remember 30+ years ago all the parts houses would sell you a 16 degree impeller saying it was better. I guess lugging the engine down below 6000rpm would work well with the small carb. At 6600 the CDK2 38mm was better, about as good as I could get from a pump gas limited. After that we used a pair of 44s with a higher ported cylinder and race gas compression. Usually with a Dales ignition or MSD total loss. All this with a shortened Coffmans could turn 7000rpm.
 

WFO Speedracer

A lifetime ban is like a lifetime warranty !
Location
Alabama
I am going to show my age here just a bit but I am old enough to remember 28mm carbs being installed on Professional freestyle skis back in the day, why because they gave a wide linear powerband with no hicckups or surprises, back when freestyle was hood tricks, log rolls and Australian backwards barefoot that is what was required, so to say they are junk is inaccurate , are they too small , probably, are they holding the ski back, definatly but they ran just fine for years on end on stock skis with no issues whatsoever.

By the way I can still do an Australlian backwards barefoot and barefoot off the side of a ski.
 

WFO Speedracer

A lifetime ban is like a lifetime warranty !
Location
Alabama
It could be as simple as bad spark plug wires really all we are doing is guessing here, you would have to take some ohm and AC voltage readings both cold and after it starts acting up to determine what is failing, a spark checker might also be a wise investment . I have also seen stators get hot and stop sending the correct voltage to the CDI.

I have seen spark plug wires with a series of breaks in them as many as 20 breaks in the wire length, the OEM spark plug wires are pretty much crap .
 
Best of luck on your diagnosis. I too would check CDI, but wouldnt hurt to clip 1/4 inch from the spark plug leads to make sure no corrosion is keeping you from revving out. Also check the voltage regulator too since you are there for CDI. Furthermore take the hood off when it happens and let it vent for 5 - 10 minutes. See if it happens again. If not you may have an exhaust leak that is filling up inside the hood while riding. Then it makes it to where the engine cant breath and it wont rev out either.
 
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