Updating/restoring a K&B 40 #8011

[DaleCS]

I have K&B 40 (sn 43263) that I received from my Dad when I was a kid. I've got the engine running, but have a problem with exhaust noise.

I'd like to put a better, up to date muffler on it, but have two problems:

- the 8061 crankcase (K&B oval logo, not the "Torpedo" logo) was designed with a set of holes in the exhaust manifold for the use of an exhaust rotor (8039).
- the front part of this exhaust manifold area was damaged in bad landing (crash, really) - there's a chunk metal missing from this area

I have an old exhaust that slips over the exhaust manifold, covering the rotor holes, including the missing chunk of metal. However, this exhaust barely muffles the engine at all, so would not meet today's standards.

Today's mufflers don't slip over the exhaust manifolds of engines - they butt up against the exhaust manifold and the muffler bolts run through holes in the crankcases.

So, what to do? I've thought about:

- filling in the rotor holes, missing material with something; then, perhaps using the muffler strap from my old muffler to hold one of the new style mufflers in place
- continue looking for an adequate muffler that will slip over the exhaust header
- replace the crankcase with an up to date version that will work with current style mufflers; I expect that I'd probably need to use a new cylinder and probably a new ring, too

The engine runs great, and I'd like to get into something this winter.

Any suggestions?

Thank you.

Dale

PS: I've also got an old K&B 35 #7861. Getting this running again will have to be my next project.

[MECOA]

The best bet is to use a new crankcase and muffler. part numbers 10-4001 and 30-4001

All your old parts will fit into the crankcase.