This Page Takes A Brief Look At Wildcat Equip Tuning By Geoff Stephens.

I started out working with Les Rafferty, the Rafferty Newman Wildcat Scooters engineer, from the late 60s till his death in 1977. I was involved in tuning, preparing and racing the Wildcat works race bikes.

My first race scooter was a new 1969 Vega converted to 125 with a 5 port race cylinder and my first race meeting was at Lydden in late ’69. I came very near to winning the 3rd race of the day. Due to my inexperience I let Nick Barnes beat me by a wheel over the line, he had a 125 GP before they were available in this country.

Pic: Geoff Stephens 1969 GP 150 Wilcat Racer...

I was involved with helping Tony Wilcox, the sidecar champion in our club, develop lumenition electronic ignition to fit a Lambretta race engine. This was in the early 70s.
Les Rafferty and I did a reed valve cylinder similar to a TS1 with the reed valve fitted into the inlet port and the inlet manifold exiting from the right side to clear the frame. We used a cast iron GP 200 cylinder and a Yamaha reed valve of the period. I made the reed block and inlet manifold by hand from solid aluminium and tube. This again was in the early 70s.

I won my first race at Castle Combe in 1971 riding the works Wildcat 225. We had fitted a flat topped Powermax piston with a Dykes ring made by Hepolite and to get the compression ratio up to an effective level I made a GP 125 head with a centre plug fit a 70mm bore and 200 stud spacing. It lasted long enough to win at Castle Combe.

I built an SX 200 Group 4 race bike with Les and was leading the 1975 Championship when Dave Webster crashed just in front of me going round Dover slope at Lydden. I took evasive action to avoid hitting him as he lay in the track and crashed head on into the chalk bank. I broke my wrist, my ribs and ruptured the muscles in my left leg which is still numb and swollen to this day. All that was left of my SX to use again was the engine and back wheel.
I then built my GP 150 Group 3 race bike with a friend, Richard Arm, who bought the bike and help sponsor me in racing. I took on Dave Webster who was the group 3 champion at the time. After a year long battle with Dave I won the Group 3 championship by 1 point, unfortunately my friend Les Rafferty died of a heart attack early in 1977 aged 48 and did not live to see me win. I decided to continue on my own, tuning and developing race engines and scooters.

It was at this time that I met Roly Caldecutt who had been racing motor bikes and came into scooter racing. He was a very talented engineer – chief engineer at Southampton University. He built a hub centre steering and sidecar steering combo for Alan Crickmore and Pete Hinsley. I was involved in the engine development. They raced it successfully winning the championship till it was banned because the technology was considered excessive for a scooter sidecar. Roly modified the outfit to conform to the regulations and Pete and he started to race it together.
They were also racing Group 5 solos.
I started to do both their engine tuning helping them both to win races. At this time 1980, I started to lose interest in racing myself and retired my Group 3 150 which I still have today. I took over the full development and preparation of Roly and Pete’s combo.
At this time I had developed an engine using a 70mm Yamaha Dykes ring piston from a DT 250, we used this set up on Roly’s Green Meanie Group 6 racer and the combo. We also built a short stroke version of the set up, Roly made up a 54mm crank as they were not commercially available at that time. He did this by boring and pinning the rod 180 degrees round the other side of the crank. The idea was to use it in the sidecar outfit but the power characteristics did not suit a combo so we fitted it in the Green Meanie.
I would ride it in group 6 to develop the engine and Roly and Pete would use the 58mm stroke version in the sidecar outfit. I rode the solo at Lydden at the next race meeting and won both races first time out.
I was also helping Tony Pawsey with his Group 5 Special and he won the class and overall championship. Later on I helped Steve Ives win both championships on his group 3 150 Standard. My input with these bikes was mainly advice particularly on carburation and set up though I did strip and rebuild Tony’s gearbox to resolve a reliability problem.
 
I rode the Green Meanie Group 6 race scooter for the last time at Lydden. Roly wanted to ride it as well as race the combo so I retired from racing and did full time development of these engines. We managed to be very competitive and win races in both classes.
Then Ray Kemp announced the TS1. I obtained one in 1984 and we started to develop it for the sidecar outfit. We were the first race team to win a race using a TS1 and then a championship. Roly also went on to win the Group 6 Specials championship on a TS1 all tuned and prepared by me. I also had help from an old tuning friend who was in his 70s – Ray Snowed, a very talented 2 stroke tuner and engineer who advanced my knowledge of 2 stroke engine dynamics.

As an aside I believe I invented the case reed engine induction system years before Yamaha used it on their race engines. I had mocked one up on a Lambretta crankcase, I should have patented it!
I believe I also did the first 186cc using a 64mm RD 400 Yamaha piston in one of my 150 race cylinders bored out. This was in the late 70s, I still have the cylinder piston and head to this day.

During these years many people asked for my advice particularly on carburation. I’ve had thousands of spark plugs thrust under my nose for my opinion on how their engines were running. I remember solving a fuel starvation problem on Ralph Remnant’s sidecar outfit at Pembrey when he started using a TS1. This long circuit with flat out in top gear straights and curves showed it up, he thought it was an ignition problem but it was fuel starvation caused by too low a head of fuel for a TS1. He fuel pumped the engine and the problem was solved.

I was involved in the International Scooter Race at Curcuit Carole near Paris, named after a girl who was sadly killed in a motorbike accident. I became team manager and helped to get 1st, 2nd and 3rd for the English team - Simon Baker Taffspeed, Mike Davies MBD and Stuart Day.

There have been many engines of race scooters that I have helped to improve, too many to remember them all over the 40 years of involvement in scooter racing at the highest level in this country. Probably the single most successful was Mark Caldecutt’s Group 10 70cc Zip SP Auto. Mark was a phenomenal rider once he gained experience. In my opinion the best solo scooter racer I’ve ever seen. He won a great many races on this scooter I tuned and prepared for him with him learning from and working on it with me. He amassed 5 Group 10 championships, 2 overall British Scooter championships and in one season he won 17 races in a row – the only thing that stopped him winning his 6th Group 10 championship and 3rd overall British Championship in a row was an emergency hernia operation. This put him out of racing for 2 months and cost him the championships he deserved but as they say “That’s Racing”.

I still get asked for advice if I go to a race meeting and will help on any problem I believe I can understand.

I don’t know it all and I am still learning at 63 years young.....