1939 Rudge Special

**Hoghead** · 12-27-2022, 5:20 AM

Good bones! I have a book on Brooklands MC Racing in the interwar period- if you want it i'll send it to you.
Rode a Rudge Special -was smitten - great ride. Hope you find an Ulster head!!

**Dexter** · 12-29-2022, 3:26 AM

That's very generous thanks I have not ridden one yet...... the Ulster although the faster bike from the factory has a more complicated rocker arm arrangement and being heavy bronze and high up is not good for what I am planning but the game plan is to use the Special head which is iron and port it to Ulster spec or better and open up the exhaust ports to accept a 1.5 Id exhaust pipes.

First job I tackled was the worn sprocket, this like an old Triumph style where the sprocket is cast / forged as part of the drum brake so needed machining off and a new sprocket welded back in place - although the Rudge club and other sources have a good replacement spares this is not one of them.

The lathe we have is not big enough to take the brake drum before the teeth are removed so most of the machining was done on the milling machine then lathe - bit of messing about but please with the end result.

Attached Files

**DustyDave** · 12-30-2022, 7:55 PM

Definitely the kind of build I like! Old, not enough parts with lots of home machining. My 41-50 Scout started as a pair of cases that I bought for wall hanging. Anybody can buy a running late model and hang a few aftermarket parts. It's quite different when half of what you need is made of unobtainum.
Dusty

**Dexter** · 12-31-2022, 2:53 AM

Originally posted by DustyDave

Definitely the kind of build I like! Old, not enough parts with lots of home machining. My 41-50 Scout started as a pair of cases that I bought for wall hanging. Anybody can buy a running late model and hang a few aftermarket parts. It's quite different when half of what you need is made of unobtainum.
Dusty

Thanks Dave its going to be interesting that's for sure

**Hoghead** · 12-31-2022, 10:52 AM

Originally posted by Dexter

Thanks Dave its going to be interesting that's for sure

Nice work so far! Always fancied a Rudge. This one was knocked up from parts in the Czech republic. They go as good as they look.

**Dexter** · 01-02-2023, 7:45 AM

Originally posted by Hoghead

Nice work so far! Always fancied a Rudge. This one was knocked up from parts in the Czech republic. They go as good as they look.
[ATTACH=CONFIG]109653[/ATTACH]

That looks very nice

**Dexter** · 01-06-2023, 5:20 AM

Next up was the rocker cover this is normally held in place with a central fixing which is a plug threaded into the top of the cylinder head, this makes the conversion to a central spark plug fairly easy but requires a new method for the mounting of the rocker cover - a few ways this could have been done but this was mine. Still to machine down the tubes in the last picture.....

**Dexter** · 01-18-2023, 5:16 AM

Next up its time to replace the steel engine/gearbox plates and front engine mount plates with aluminium. There were lost of ways this could have been done but the method i chose worked with the tools and equipment I had (oh for a band saw.....) Not all the mounting holes needed to be replicated as things like the main stand will not be going back on this bike. This frame design has an open bottom where the plates and the engine are part of a stressed member.

**Dexter** · 01-28-2023, 8:39 AM

For the front wheel and for that matter the rear wheel i wanted to go away from the Rudge design for spoke locations, if you have never looked a a Rudge wheel before the spokes are set so they are evenly pitched with alternate spokes fixing to the centre of the rim and then to the outside of the rim so wider rims and alloy ones specifically would be out. My plan and one I have seen others use is to ditch this arrangement and go with a traditional spoke locations E.G all to the centre of the rim.
So for the front I am using a BSA Goldstar front hub and brake plate and with the rear I will be sticking with Rudge hub and brake setup but re spoking to allow a flanged rim to match the front. BSA designed the Goldstar front spindle to be used to pull against the bearings and then uses the 1 of the bottom legs to tighten the wheel against - no good for a Girder fork set up...still this left me to design and make a centre bearing spacer and as I needed a new spindle why not make my own out of Titanium and make some bespoke nuts....

**flatman** · 01-28-2023, 1:04 PM

Like a good stack of pancakes, made from scratch. LOL

**TriNortchopz** · 01-29-2023, 8:43 AM

...replace the steel engine/gearbox plates and front engine mount plates with aluminium.

nice, and a whole lotta holes... I use an arm powered hand-held hacksaw for cutting aluminum plates...and many twisted blades.
How thick were the original steel ones compared to the aluminum plates?
Great work on the wheel adaptation.

found this for those interested in Rudge:

The Motorcycles

History of Rudge Whithworth machines
"From its foundation in 1894 the Rudge Whitworth company built a reputation for quality, reliability, sporting prowess and innovation with many patented ideas reaching the production machines.
... In the final year of manufacture in 1939, the cylinder head was cast from RR50 light alloy with iron valve seat inserts..."

The Motorcycles

https://www.rudge-whitworth.com/the-motorcycles

The FREE technical site for Rudge Enthusiasts.

**Dexter** · 02-01-2023, 6:35 AM

Originally posted by TriNortchopz

nice, and a whole lotta holes... I use an arm powered hand-held hacksaw for cutting aluminum plates...and many twisted blades.
How thick were the original steel ones compared to the aluminum plates?
Great work on the wheel adaptation.

found this for those interested in Rudge:

The Motorcycles

History of Rudge Whithworth machines
"From its foundation in 1894 the Rudge Whitworth company built a reputation for quality, reliability, sporting prowess and innovation with many patented ideas reaching the production machines.
... In the final year of manufacture in 1939, the cylinder head was cast from RR50 light alloy with iron valve seat inserts..."

The Motorcycles

https://www.rudge-whitworth.com/the-motorcycles

The FREE technical site for Rudge Enthusiasts.

[ATTACH=CONFIG]109842[/ATTACH]

So the steel plates were 6mm I made the Aluminium ones from 8mm - yes lots of ways to skin the cat and making swarf but that was my chosen route with what I had available to me, a bandsaw would have been soo much easier.

Rudge were on the higher end of the British bikes and did well at IOM which helped, supposed to be one of the first bikes to have duel operated brakes.