Post by mooreperformance on Feb 18, 2012 19:34:45 GMT -5
Three engineers left Polaris in 1971 (Jerry Reese, Marley Duclo and Mike Baker) to start Brut Snowmobiles. The 1972 Brut snowmobile used a new design Salisbury drive clutch (a poor copy of the Polaris clutch). The clutch was a pile of junk.
The 1973 Brut was fitted with a new drive clutch designed by Marley Duclo. This clutch had the Brutanza Engineering name on the cover. It was similar to the Scorpion Power Thrust II.
Jerry Reese was hired by Scorpion as an engineer when they purchased Brut.
Marley Duclo went his own way.
For the 1976 season Duclo revised the Brut clutch and called it the Duclo clutch and sold it as an aftermarket replacement clutch. Scorpion purchased it from Duclo and installed it on all of the 1976 (and newer) models. Scorpion named it the Power Thrust II.
It is a very basic clutch and most would call the Duclo design a "kidney" clutch. This name was used because the flyweights are "kidney" shapped.
Most Canadian manufacturers used a kidney clutch in the early years: Skidoo, Skiroule, Sno Jet, Moto Ski, Alouette etc. The first Yamahas and the (USA made) Rupp also used the kidney clutch.
The performance of the kidney clutch could be adjusted with a stronger or weaker main spring and by altering the flyweights. Usually by grinding a little off the "kidney" to make it lighter or adding a steel rivet to the "kidney" to make it heavier.
The Duclo "kidney" clutch was also available with different main springs and extra weight could be added (or subtracted) from the "kidney" by adding or subtracting bolts and washers.
As far as most people (that know about clutches) are concerned, the Duclo/Power Thrust II is a vary crude design and in no way can compete with a Polaris/Comet clutch.
At the time it seemed like a step backwards (by most snowmobile experts) when it was introduced on the 1976 Scorpions. By 1976 most snowmobile manufacturers had moved past the kidney weight clutches to a more modern design.
There is one big advantage to the kidney clutch, it is very simple, reliable (and the Duclo) is easily tuneable!
The Polaris/Comet clutch is very complex and you really need to be an expert on clutches to work on it and tune it!
Dennis Moore
The 1973 Brut was fitted with a new drive clutch designed by Marley Duclo. This clutch had the Brutanza Engineering name on the cover. It was similar to the Scorpion Power Thrust II.
Jerry Reese was hired by Scorpion as an engineer when they purchased Brut.
Marley Duclo went his own way.
For the 1976 season Duclo revised the Brut clutch and called it the Duclo clutch and sold it as an aftermarket replacement clutch. Scorpion purchased it from Duclo and installed it on all of the 1976 (and newer) models. Scorpion named it the Power Thrust II.
It is a very basic clutch and most would call the Duclo design a "kidney" clutch. This name was used because the flyweights are "kidney" shapped.
Most Canadian manufacturers used a kidney clutch in the early years: Skidoo, Skiroule, Sno Jet, Moto Ski, Alouette etc. The first Yamahas and the (USA made) Rupp also used the kidney clutch.
The performance of the kidney clutch could be adjusted with a stronger or weaker main spring and by altering the flyweights. Usually by grinding a little off the "kidney" to make it lighter or adding a steel rivet to the "kidney" to make it heavier.
The Duclo "kidney" clutch was also available with different main springs and extra weight could be added (or subtracted) from the "kidney" by adding or subtracting bolts and washers.
As far as most people (that know about clutches) are concerned, the Duclo/Power Thrust II is a vary crude design and in no way can compete with a Polaris/Comet clutch.
At the time it seemed like a step backwards (by most snowmobile experts) when it was introduced on the 1976 Scorpions. By 1976 most snowmobile manufacturers had moved past the kidney weight clutches to a more modern design.
There is one big advantage to the kidney clutch, it is very simple, reliable (and the Duclo) is easily tuneable!
The Polaris/Comet clutch is very complex and you really need to be an expert on clutches to work on it and tune it!
Dennis Moore
