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## Introduction...

## Blog Archive

## Gearing Calculator

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Gearbox ratios are for a standard four speed AMC gearbox.

To return the script default values use refresh in your browser plus the control key.

## Smiths Chronometric Speedo Fitment

## Motorcycle links

## Other Links

## About Me

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Nine years ago I moved from London to Seattle, WA and once I settled down and figured that I would be here for a while it was time to find a cool ride to keep me busy and out of the pub. I settled on a 1942 BSA M20 - an old English army bike on which I could relive all of my Steve Mcqueen fantasies of exciting chases and jumping barbed wire fences.

After much searching I found the bike I was looking for, rough but complete, and after two years banging away in the tool shed I emerged proud as punch and ready to take on the streets. I took my motorcycle test and I was soon racing around trying to escape from prisoner of war camps. Now anyone that has ridden one of these old BSA's will know that you are not going to be able to escape from anyone, and the thought of getting airbourne to flee the country, well, it just isn't going to happen.

Four years later, and I started to realise that 60 mph is a bit of a crap top speed, and suspension might make rides over 2 hours a little easier on the back and arse. So I started hunting for a new project. I came accross a 1956 Norton Dominator Featherbed frame complete with Roadholder forks and decided a Triton was going to be the next project. I soon found a 1958 Triumph T110 650cc motor and a Norton Gearbox (thanks to our friend Ebay) and the major components were there. Atleast that is what I thought.

This blog is an attempt to catalogue my struggles of putting this bike together. Be patient, it might take some time....

Gearbox ratios are for a standard four speed AMC gearbox.

To return the script default values use refresh in your browser plus the control key.

The calculation for determining the speedo series number is

1680 x A/B, where

A is the number of turns of the speedo cable for six turns of the rear wheel;

B is the radius of the rear tire in inches;

1680 is a constant.

Find the drive ratio as described in my post above. Let's say it's 2:1. Let's also say the tire radius is 13.1 inches. The calculation then is 1680 x 6 revs x 2(drive ratio) divided by 13.1 inches equals 1538.9. This number is within 10% of 1600, so in this case a 1600 series speedometer head is required. (A 15 to 12 drive will alter the number to 962, in which case a 1000 series speedo is required.)

This gets you to within 10% which is the adjustment range of a Smiths unit. The final tweaking can be done internally by a specialist. Or the unit might be spot-on, as is.

1680 x A/B, where

A is the number of turns of the speedo cable for six turns of the rear wheel;

B is the radius of the rear tire in inches;

1680 is a constant.

Find the drive ratio as described in my post above. Let's say it's 2:1. Let's also say the tire radius is 13.1 inches. The calculation then is 1680 x 6 revs x 2(drive ratio) divided by 13.1 inches equals 1538.9. This number is within 10% of 1600, so in this case a 1600 series speedometer head is required. (A 15 to 12 drive will alter the number to 962, in which case a 1000 series speedo is required.)

This gets you to within 10% which is the adjustment range of a Smiths unit. The final tweaking can be done internally by a specialist. Or the unit might be spot-on, as is.

- Britbike Forum
- Clubman Racing Accessories
- Disco Volante Moto
- Dresda
- European Motorcycles Inc.
- Fair Spares America - Norton Parts
- Independent Ignition Supplies - Magneto Spares
- International Title Service
- Johnson Motors
- MAP Cycle
- McIntosh Racing - Norton Manx Part Suppliers
- Morgo - Makers of big bore kits
- Norvil Motorcycle Spares
- Old Brittts - Norton parts in Seattle WA
- Royton Precision Tooling
- SRM Engineering
- The Tank Shop
- Tri-Cor England
- Triumph.com - not what I expected!
- Unity Equipe

- Curry Frenzy - more curry recipes than you can shake a stick at.
- New Model Army - coming soon to a town near you (probably)
- Nice Cup Of Tea And A Sit Down
- Sad Kermit - and who can blame him.
- Timothy Hull - Good friend, musician and curry cook extrodinaire!
- Timothy's adventures in Portland and the rest of the planet. But mostly Portland. (Now available in blue.)
- Unravel Massage and Bodyworks - Langley WA

## 4 comments:

Been reading you blog, and found it very informative! The wife banned me from driving MC's a few years back. It was fair enough, as i couldent figure out, how to drive mine at a regular speed. Lately she has opened up for the idea of a "veteran" bike. And since then i have been researching which bike would be my best fit. I quickly have found a soft spot for the idea of a cafe-racer. And the Triton, is an obvious choice, for some reason, i dont quite understand and cant put into words. Money is a problem as it is for most people i assume. Your blog was just what i needed, before reading it i had a million questions to ask.. To see all the effort and money you have put into it i have come to realise, that there is no way i can ever finish a project like that. This might not sound positive but it is.. I was about to buy and old heap of junk, and try to restore it. Now i know that i need to save up some money, and buy it in working condition. I hope that you will get back to work on the projekt one day, i would for one have loved to see the finished result!

Good luck

Søren

was this project ever completed or did the family, new kid, make the project go away?

Thanks for the interest. The project has not gone away but is at a bit of a stale mate. Will update soon with some new pictures!

looking forward to the continuation. i just picked up a Triton project which is (or will be) very nearly the same setup, and i'm moving to WA too. we'll have to compare notes!

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