One of the guys on a Facebook BSA M20 page sent me a video of a Harley Knucklehead cylinder grafted onto a BSA crankcase. Has anyone done this? He says you can also put a panhead cylinder on.

The video looks pretty interesting, and it's a very "antique" looking engine.

Any info would be appreciated as I have a good bottom end, but no top end.

Thanks

email (option): britool51@hotmail.com

Anything is possible. Were is the video Robb? I like weird things and other guy's engineering skills. I've seen a Harley 45 engine with 350 ohv Matchless barrels and heads. Ron

email (option): ronpier@talk21.com

It does figure, as many of the side-valve bottom ends seem easily converted - its the crankcase stud centers that usually define what you can do.

I was playing with a 16H bottom end and thinking of making a OHIV conversion - like an Aquaplane 100E head I had years ago -
While messing, I realized a BMW1000 barrel and head (i was racing one at the time) could be grafted on, with minimum effort.
Even less machining was needed to fit the 750 BMW cylinder (smaller barrel spigot).
Roughed it out, but never finished it as I became involved in a BMW F2 outfit for Dave Saville and Sabre racing.

I've seen a Porsche Cylinder and head bolted onto a B44/50 (cannot remember which) bottom end - these have the same crankcase/cylinder stud spacing .......

The M20 can be fitted with an iron Sportster top end as well, and a 350 Matchless...I've seen both of those running...

As Nigel points out the permutations are probably numerous ones you get down to looking at various engines....

You might ask why you would go to all that trouble though when a B33 would pretty much do the same job and can itself be tuned and enlarged if needed....

Then again, playing about and creating your own project is a large part of the fun in this game if you are into the engineering side of it and no one said the result had to be logical...Ian

email (option): ian@wright52.plus.com

Here's a nice tidy conversion Ian!

It takes skill to bend an exhaust pipe like that.. ..and to think I told the pipe bender who made my last 'special' if he distorted the tube I wouldn't pay for it....

I guess it's a bad ass bar hopper/survivalist/rat bike/ enjoy the haemorrhoids later custom..or something...

I think I'm too old to be cool...Ian

email (option): ian@wright52.plus.com

email (option): horror@blueyonder.co.uk

Scroll down on this page for a few other examples http://www.diagnosis2012.co.uk/halfadavidson.html

I am actually thinking of doing this sometime in the future. I think a knucklehead would go better with the look of the girder forks and the rest of the bike. However, they are I think more expensive than shovel cyls and heads, From what I've gathered the three main worries are:
Bolting patterns cylinder-crank cases
Piston hight/stroke/compression ratio
Angle of push rods and push rod tubes

Maybe in 5-10 years or so I'll be posting pictures of my build...

/s

I have a knucklehead engine in pieces if anyone needs any more measurements!

email (option): davmax@ntlworld.com

Hi Ron, The video is on my Facebook page. It came from John Gleeson who lives on the Isle of Man.

email (option): britool51@hotmail.com

On the lever follower Norton engines, only the Exhaust cam is 'Bigger' - i.e. more timing and a tad more lift.

Why to do such things - I think many of us dream of building our own engine, to fulfill a specific task - a MONSTER single, fast SV, etc.
Castings can be expensive to have made and machined, so the logical choice is to use existing components
Mix an Match

I've seen some epic's in the past - one a friend build always blew my mind - 4xHonda 160 top-ends on a welded (ali) crankcase, with an Imp crankshaft (I suppied) and ....... V8 OHC screamer ...
Revved to well over 10K - in the 1970's - all installing I a 250 Rudge chassis ..........!

He did have to take one set of heads off to change the inner spark plugs though.

UTube now has some really awesome stuff from around the world.