K&B 4050 Crankcase Failures

[Walter Gifford]

I understand there is a thicker crankcase being made for the 4050 type engine.

Is this part number 10-4002 or, will it have a new part number or, be special order?

The 4050 is ok from the factory but, when modified for maximum performance the whole cylinder breaks off just above the exhast port.

The modified 4011 actually puts out slightly more power but, it doesn't burst apart because the O.D. of the liner is smaller leaving more metal in the crankcase. The 4050 has a bigger O.D. on the liner so the case has to be bored out too big and thin.

It's easy to fix, just don't cut the cooling fins so deep.

Let me know how to get the new thicker crankcase because, I want to build another smokin' 4050 that will keep it's head on.


Thanks, 8)
Giffy

[MECOA]

Yes the new 10-4002 is the thicker one. There were none left when we bought K&B. We reworked the casting dies and ran all the parts. The cases are all done except for drilling and tapping the holes. What can I say, I had/have to make new fixturing up for most of the K&B line. This crankcase in particular is hard to drill the head bolt holes as the holes are dead center to the ridge for the sleeve recess. It has to have a good center drill or 1/8 end mill to start the hole.

Keep an eye on...

https://shop.mecoa.com/shopdisplayproducts.asp?id=140

for availablilty