KEC 440/21 vs 22

stinger440 · Post by **stinger440** » Fri Aug 10, 2007 1:17 pm

Hey guys. Been a while and digging back into this motor. I have a KEC 400/21 sitting around and I was wondering due to the lack of top end parts for this motor, could I put 440 cylinders on the same case? Since the stroke is the same could I put a 440/22 crank in those cases so I could have some piston choices. Thanks in advance.

Rodimus Prime · Post by **Rodimus Prime** » Fri Aug 10, 2007 9:27 pm

actually you only need to change the crank to use the /22 pistons.

stinger440 · Post by **stinger440** » Wed Aug 15, 2007 8:28 am

Will the 440 jugs fit on a 400 lower end? Thanks

Rodimus Prime · Post by **Rodimus Prime** » Wed Aug 15, 2007 10:34 am

the crankcase housing flywheel manifolds are the same from 340-400-440 the diference is the bore. the /21 have a smaller piston pin than the /22. For what its worth though the 400 model of these produces the better power. My 74 x6 lifts the skis which is impressive with the heavy suspension.

stinger440 · Post by **stinger440** » Wed Aug 15, 2007 12:29 pm

Thanks for the info. I want to keep the 400. My concern is the motor is already .020 over and if anything happens to it, I haven't been able to find another set of pistons for the /21 or 400 jugs.

Rodimus Prime · Post by **Rodimus Prime** » Wed Aug 15, 2007 2:00 pm

there was some nos pistons for the 400/22 engines on ebay awhile back from dk trader they may still have some.

cyclone crazy · Post by **cyclone crazy** » Tue Sep 11, 2007 1:28 am

I have pistons up to .040 for your 400/22

stinger440 · Post by **stinger440** » Wed Sep 12, 2007 8:24 am

I will remember that cyclone crazy. Do you happen to have any for a 400/21 or 440/21?

cyclone crazy · Post by **cyclone crazy** » Wed Sep 12, 2007 10:48 am

Yes 440/21 - 16mm pin - standard .010.020.040
nothing for the 400/21

stinger440 · Post by **stinger440** » Fri Sep 21, 2007 3:09 pm

Here is another "what if?" to throw out there. I don't know what is specail about the shape of the piston of a CCW RV engine. I know my 400/21 is 65mm with a 16mm pin. I found an Arctic cat piston that is 65mm with a 16mm pin. Would it be possible to use this as a replacement. Just curious, I don't have any pistons to compare.

JDFanPa · Post by **JDFanPa** » Fri Sep 21, 2007 8:54 pm

The right diameter and pin size isnt enough you need the same deck heigth and skirt length also the ports are another problem.

Rodimus Prime · Post by **Rodimus Prime** » Sat Sep 22, 2007 4:01 pm

the top of piston to piston pin hieght is important so are the placement of the pins for the rings. the skirt can be trimmed if its a little longer. if skirt is shorter on a reed valve engine wont make a difference as skirt doesnt open or close ports. the stock skirts are angled for a better flow rate at higher speeds but it isnt absolutly nessecary.