Curtis Racing Frames - A History

DT_Mania

Super Moderator
Joined
Mar 31, 2014
Messages
4,311
Reaction score
21
Denis Curtis

Denis Curtis, CMR owner, was born in Lincolnshire, England in the late '40s. He served an apprenticeship with a local engineering company called Ruston-Bucyrus Limited and became a Jig and Tool Design Draftsman. He attended a local Technical College during this time and gained a Production Engineering Degree with the City and Guilds of London Institute.
Denis was influenced by many racing motorcycle frame builders of the 50s, 60s and 70s, including Ken Sprayson of Reynolds Tubing and his work with many top riders of the era like Mike Hailwood . Other influences include Colin Seeley with his solo and sidecar frames and the Rickman Brothers and their Metisse frame kits for all types of motorcycle sport. Also of note was Alf Hagon with his V-Twin JAP Sprint Bike, and the Eric Cheney Organization whose Motocross frame exploits were of the highest standard.

Denis Curtis started building and modifying frames for road racing and sprinting (drag racing) in 1965 in the UK. His first projects used Velocette and Vincent engines. After emigrating to British Columbia, Canada in the early 1970's and working and road racing for Fred Deeley Limited, he started his own manufacturing shop called Curtis Racing Frames in Richmond, British Columbia, Canada.

Curtis Racing Frames operated from 1973 to 1977, producing motorcycle frame kits for all type of racing and street activities. There were a total of six employees. The shop was just across the road from the Fred Deeley Yamaha HQ, which later became Yamaha Motor Canada. The racing division of Fred Deeley Yamaha and Yamaha Motor Canada were frequent visitors to our shop. We enjoyed a close working relationship with them and also with Clarke Simpkins Honda, the Honda motorcycle distributor in BC at that time.

At the top of this page are a selection of links to pictures of some of Denis Curtis' exploits with motorcycle racing and motorcycle frame building from before and after 1970 when he emigrated to Canada.

The 1960's

First ever road race – 1965. Riding a friend's BSA 350 cc Gold Star in a Clubman's Race at Cadwell Park race circuit near Louth, Lincolnshire, England. I finished 3rd. The bike was absolutely stock except for a fiberglass gas tank. Details: ran on Avon tires, used a period 'Everoake' 'pudding basin' helmet and a set of used 'Lewis' leathers. I rode the bike to the event, taped up the lights, put on the number plate and went racing! Because I was only 16 years old, I had to get my mother to sign the waiver. My father didn't know I was racing.



My home track, Cadwell Park in Lincolnshire. This is the Vincent Owners' Club High Speed Trials, 1967. I'm waiting for the 'out' on my Curtis Vincent Special #32. In this line- up is Roger Slater on bike #2. He became the Egli-Vincent distributor for the UK.



A photo of the first time the Curtis Vincent Special was raced at Cadwell Park in Lincolnshire. The bike used a 998cc Vincent V-twin engine with the standard transmission/gearbox removed. The engine was mated to a Manx Norton 4-speed gearbox/transmission. I built this bike in 1966/67 to compete in the Clubman Open racing class.

I used a Manx Norton frame and re-engineered it to put the Vincent engine crankshaft on the same centre-line as the original Manx Norton engine. The frame had to be extensively modified – as you can see from the photo, the front down tubes have been removed. The engine had been modified for racing to “Lightning spec”. I even used the Manx Norton central oil tank. Dunlop racing tyres were used and Girling shocks. It was a cold day and I scared myself silly on this thing. It was my first outing on those old triangular tyres and you needed to get some heat into them so they would work properly.





I had two set-ups for different race tracks. For Snetterton and the long track at Cadwell I used 1 & 5/16" Amal 5 GP2 carburetors on special adaptors. For shorter tracks I used 1 & 1/8" Amal monoblock carbs. The bike had lots of torque, and handled really well. After a couple of seasons I realized that I wasn't a very good road racer, as I was more interested in building great handling machinery than racing them.


 

DT_Mania

Super Moderator
Joined
Mar 31, 2014
Messages
4,311
Reaction score
21
The 1970's



The Curtis Vincent Special was noticed by many people at the race tracks we visited. I received orders to build a number of replicas. These three photos show one of those frames being used by Stuart Howe of Leicester, England, in the early 70's. I had left England for Canada by then, but I understand from Stuart that he raced his Curtis Vincent Special up to the mid 80's with great success. Thanks to Stuart for the pics of a wet Silverstone in 1972. He was very fast in the wet!



Worthy of note here:
Stuart Howe used to work for Vincent sidecar racing specialist Peter Russell of Leicester UK in the '60's and early '70's. Stuart did a lot of the engine preparation and on his bike here, he's using a Dunstall front fork/dual disc brake assembly with the calipers built into the fork legs. Notice how small diameter the disc rotors are.



I came to Toronto in early 1971 and worked in the aluminum extrusion design area for Alcan. I had friends in Vancouver, so after building a Norton Dominator / Commando special from pieces, I found myself in Vancouver by late summer, having crossed the country on this motorcycle. I took a job with the Fred Deeley organization at their retail store at 606 East Broadway, Vancouver. The store sold Harley Davidson, BSA, Triumph, Yamaha and some others, and was run by Trevor Deeley.



I was involved in the service and parts department, and shortly after joining Deeley's, I found a tough looking BSA Spitfire Mark II in one of the back rooms. It turned out to be a bike that Trevor had purchased in the Isle of Man in 1968 or 69. I was told it was Ray Pickrell's works BSA 650 Twin Production TT racer. It certainly was trick.
I asked Trevor if I could rebuild this bike to race in local events at the club level. It started out with original BSA brakes but to compete with the 500 Suzuki 2-strokes I converted it to use Yamaha TR 350 wheels and brakes, front and rear.



The Fred Deeley Retail store had a paint shop, and 'Joe the painter' always came up with a fancy paint jobs for the bike and my helmets. At that time Trevor Deeley was running Fred Deeley Yamaha Canada Ltd., and Joe painted all the race bikes – he was very good.



These pictures were taken at Westwood race track, which used to be located in Coquitlam just outside Vancouver. It was a fabulous track used by both motorcycles and race cars. To make another track, we just reversed the direction of travel! It's now a housing estate.



Trevor Deeley allowed me to race the BSA twin at some western USA tracks e.g. Seattle Washington & Portland Oregon, and as far east as Edmonton. It was quite competitive. During this time I was still keenly aware of new motorcycle design happenings in Europe and UK, and decided to build my own Seeley replica using a Norton engine.

 

DT_Mania

Super Moderator
Joined
Mar 31, 2014
Messages
4,311
Reaction score
21
Frames

Flat-Track

Curtis Racing Frames sponsored US AMA National Pro #32, Randy Skiver during 1973 – 1977. Randy rode our frames in both the US and Canada. He is featured here on Curtis Racing Frames XL Honda single cylinder and on BSA 750 twin bikes. Randy was an excellent rider and gave us a lot of great feedback on frame design.





During this time the local flat-tracking enthusiasts in Vancouver, some of whom were Lions' Club members, decided to run racing events in the fall and winter in Vancouver's Pacific National Exhibition Agrodome (on concrete) and at Cloverdale horse arena (on dirt).



Motocross

Honda Motorcycles were distributed in BC at that time by Clarke Simpkins Honda. When Honda released their Elsinore 250 and 125 cc moto-cross machines in 1973 many purchasers found that the suspension needed improving. Simpkins Honda provided us with parts to produce new swing-arms with more rear suspension travel. We also provided complete frame kits for the Elsinore 250.



Worthy of note:
This picture shows one such machine. We used a layout similar to the event-winning Husquvarna moto-crossers of the time. It proved to be very popular. We used a variety of rear shocks – Boge-Mulholland, Red Wing, Girling and Koni, to name a few.

Enduro



These photos show our early version of Honda XL350 enduro/cross-country bikes using both Honda XL350 and Elsinore parts.





This bike evolved over several years and went from twin down tubes to single down tube and greatly modified rear suspension with lay down and moved up shock options.




Drag Racing

This photo shows a chassis built for a Canadian customer who wanted to compete at Bonneville Speed Week on the Salt Flats at Wendover Utah



Curtis Racing Frames built several drag racing motorcycle frame kits. This one was made to fit the early Honda SOHC 750 4-cylinder engine. It featured one of the 6-spoke Curtis cast magnesium wheels. The customer fitted a turbo charger and a Joe Hunt magneto. It ran and handled well.

Custom Street Machines

This series of shots shows one of the custom street machines made by Curtis Racing Frames in 1974/5. It is a Vincent engine special. Being a Vincent enthusiast, it was logical that I wanted to improve on the racing Vincent I used in the 60's, and build a sport bike for the street.









Road Racing

This series of photographs show a very interesting Yamaha 350 two-stroke twin engine racing bike. Curtis Racing Frames did a lot of work with Fred Deeley Yamaha Ltd. (which later became Yamaha Motor Canada Ltd.)






 
Top