The Mighty Garage 1951 Vincent Rapide - Part 073: Separated Rear Sprocket

Peter Holmes

Well Known and Active Forum User
VOC Member
Just been out to't shed and you will not be able to do it. :cool:
Norman, you forced me to brave the cold, I am running nylock nuts outboard, but I am only able to do this as I am running Rapide brake drums, which I guess is the whole point of the discussion, I presume you cannot do this with ribbed drums, as I always favour the Front brake, I guess we all do, I do not feel compelled to go ribbed on the rear, Ernie had the same catastrophic brake drum/sprocket failure at last years annual rally, I don't know what conclusion Ernie drew, I have had my set up for many years and miles of use, so far so good, fingers crossed.
 

timetraveller

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VOC Member
Hi Peter, I had assumed that we talking about Shadow drums. That is what I checked. I cannot see anyway in which a bolt could be inserted from behind with a standard Shadow drum. It was one of my local chums who had this happen on his Comet while out for a ride one weekend with his wife. Being a 'get up and go' sort of a chap and having his own engineering works he started to make the new Shadow drums and the hubs as well. The hubs and drums are machined from billet and there is a nice little mod to the hub design which provides two recesses inside the hub in order to drive out the bearings should they need replacing at some time. I certainly know of about four similar failures of the rear hub over the last few years. My guess is that old age is a contributing factor as well as over long bolts.
 

Bill Thomas

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VOC Member
I thought I had been told the fit between the sprocket and drum is wrong in some cases ?.
We have to make sure when fitting parts, That they feel right.
 

Ken Tidswell

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VOC Member
@Mike T 's journey with his 1951 Rapide.

Well, the rear sprocket decided to make a break for it.. thought you might like to see what I believe was the root cause!

Image below and link to a longer video with more details below the pic.

Take care everyone.

View attachment 33297

this used to happen from time to time on bikes pulling chairs . at the odd annual rally People used to spend the odd hour or two swapping the bits round so they could get home. Ordinary nuts and Loctite suffice to hold it all together
 

vibrac

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VOC Member
A good adapter is the way to go I think two drums on the back is over kill certainly you can lock the back wheel with one and as I found with the racer 5/8X1/4 MX sprockets are cheap as chips. and then there is the weight to consider..
 

Vincent Brake

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VOC Member
One uses what is readily available Robert, at least it's not 6mm which is what of the continentals use and a 3/16Whit or 1/4 BSW will not hold a 10mm AF head, I've had this out with Mr Speet, Mr Grosset & Mr Hamon, but thanks to Ian Savage we do have 1/4" Whitworth screw around the new primary cover for the Comet starters, Paul Hamon didn't really wont to give in but I'm glad he did. All my made continental stuff I've drilled out and tapped 1/4" BSF space is valuable on a bike and on trips one likes to carry a few tools & spares so that they are not required if you didn't carry them they would be. Inner tubes are to only things I've used and one spring link, but twice for other motorcyclists.
bananaman
It amazes me more DIY'ers don't end up killing themselves.
Haha gregg,

You don't hear anything from them.
So its a self solution
 

Marcus Bowden

VOC Hon. Overseas Representative
VOC Member
Greg & Vincent my handsomes, being a DIY'er all my life having to depend on my own abilities to get home on my bike or a ship to the next port. I could not afford to pay someone to spend time on my bike, selling it and buying something modern I couldn't afford that either as one has to pay out for
A) road fund licence
B) higher insurance
C) servicing as you require specialised computers
D) depreciation, capital outlay, servicing ect, after ten years a bike worth little and an empty pocket
E) keeping my carbon footprint as small as possible
F) economy as not many bikes do 200 plus miles to 15 Ltrs or a standard tank 3.25 gallons
G) LASTLY I not riding my favourite bike, 2004 we will have 60 years together, I always thought I was a youngster on a Vincent.
Bananaman
 

davidd

Well Known and Active Forum User
VOC Member
I went the MX way. Sprockets from 33T to the size of the tire. Off the shelf Suzuki RM sprockets. Just 6 bolts, no nuts. It speeds up gear changes significantly. Allows me to use 44T rear sprocket.

100_2765.jpg


David
 
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