#14 Raceknuckle

Carb again ... using the two barrel Weber DCOE40 causes two problems with this bike: first it is a really fat carb and occupies lots of room on the right side. It's a problem while driving since the leg or knee is covering the stacks. Also it's a cosmetic problem because it gets crowded as the exhaust will be on the same side.
Attaching the DCOE40 on the left simply looks weird and the manifold is too short (loss of torque).
Given this I decided to use a standard upright assembly which in turn means, exchanging the DCOE40 for an IDF40 down draft carb.

Since there's no manifold for IDF40 and Knucklehead that has each barrel and tube separated up to the heads' inlet (they are all 2into1 manifolds that in the end merge both barrels) I had to design one:

I call it "TheTubes" and it cost me quite a while to create the final version. It is twisted in the lower part, because I wanted to have the inner diameter of 39mm over the complete length of the tubes (of cause right after the top flange it goes from 40mm to 39mm). The inlet port of the head is 39mm as well.

I had a polyamide prototype made by 3D printing for fitment tests:

Fits as desired, exactly between both heads:

First thought for the final manifold was to have it printed in metal, AlSi10Mg, too. But ... after some inquiries I soon dropped that idea (the most expensive offer was about the price of the complete KN93 engine!). Currently I'm searching a metal casting company that is able to sand cast or precision cast that part. Next challenge to come is machining the flanges to measure.

Cheers,
Axel

#6 Raceknuckle

All the work on the motor internals is now done. Parts are polished and laquered to keep the churning losses minimal, crank discs are lightened to a certain extent. It's not overdone since the bike will appear on the quarter mile but the main use is as a daily runner so focus here is on a stable idling. Sunglasses on!

That's how cases should look like. Simply beautiful.

We decided not to use the S&S cam that came with the motor but to switch to a Leineweber #3.

You can check the specs here if you like.

Cheers,
pan51

#2 Raceknuckle

OK. S&S KN93. As some of the parts will be modified, polished, ported, flowed etc. etc. the motor was disassembled first. As it turns out this was a brilliant idea because a piece of debris was found as the cover and gears were removed. Remember, this is a new, unused motor!

Where does that piece come from? As it turned out, the piece was missing from one of the tappet blocks and first guess how that could have happened was that the tappet was slightly twisted upon assembly so the roller broke off the edge.

However this issue was solved quickly with the help of the german distributor by replacing the broken block with a new one. One other thing to mention is that you don't expect a lot of scratches as shown below when opening a new motor:

Just not to forget, motor and assembly work on this project will be done by Michael Schneider. Check out his website: Schneider Performance

Cheers,
pan51

#1 Raceknuckle

Well, how to start? This story is about building a new bike, based on a fake knucklehead that I bought some years ago. It sat unused in the garage for some time and after spending some time thinking about if I should burn it or use it for something fancy I decided to start a new project with it.

The good thing about it is the fact that it has a german license stating the year built is 1947 which in turn means that higher exhaust sound levels are possible, no turn lights and mirror are needed. I decided to keep only the frame and add some new parts:

Old fender is removed and a new, light one made of aluminum is fitted as well as a Mesinger racing seat. However the Mesinger doesn't fit right, looks good from side view but seen from the top it is too wide and disturbes the frames line:

Regarding the motor I'd always liked the S&S KN93 Knucklehead so this one will make it into the bike:

It will be equipped with a Weber two-throat DCOE40. The motor will be tuned a little bit, so in preparation of the tasks to come and to decide if the S&S cam is to be used the valve lift is measured:

Most parts of the motor are getting polished, heads and connecting rods for example:

Finally, to call a spade a spade I'll name it "Raceknuckle"...

pan51