Tuesday, January 26, 2010

The most powerful Royal Enfield

Don Sliger, riding a machine built by Jimmy Enz with two Royal Enfield Interceptor engines mounted one in front of the other set a record in Bonneville in 1970 of 203.16mph. It was the first time 200mph was breached on a naked bike. To keep it in perspective, no commercial bike achieves such speed even today! The feat did not constitute an official record, since that requires two runs in opposite directions and in the return run Sliger experienced clutch problems. The bike ran on nitromethane. According to the Interceptor Owners Page, the machine is now the property of Les Power in North Carolina. They have a very small picture of it, shown in the left. However, Royal Enfield Japan's Website has this picture from the National Motorcycle Museum in the UK, with the Double Interceptor. The engines were connected by gears, not chains, on the right hand side. So it is either a replica or Les Power has loaned it or donated it to the museum. More pictures of the bike in the museum are here. In addition to this, a poster in a Cycle World bulletin board has this picture of yet another Double Interceptor, where the engines seem to be linked in the primary, on the left. The rear engine seems to have the head turned, with the exhausts in the back. Finally, again in the Interceptors Owners Webpage we find this Double Interceptor Chopper with engines side by side! So I guess several bikes can make the claim of being the most powerful Royal Enfield!


  1. Twin Engine Royal Enfield....I am lucky enough to have Don Sliger's own home movies of the bike at Bonneville in August 1970, the case even has in parenthesis (203mph). Another movie is labeled "Free Roll Testing" 1969 and a few others marked Bonneville 1972 "Don's bike in pit area". I have never watched them due to not knowing how fragile they might be, but I am in the process of having them put on DVD so the family can enjoy them. Tom

  2. The movies are welcome at this blog any time!

  3. Twin Engine Royal Enfield….I am lucky enough to have Don Sliger’s own home movies of the bike. The longest one is labeled “Bonneville Nationals Aug. 1970 (203mph)” and “Nov. 2, 1969 Lakes meet (Don didn’t run)”. There is also movies labeled “10/29/1969 Free Roll Testing”, “Bonneville 1970”, “Pit Area 1972”. I have not watched them due to not knowing how fragile they are, but I am in the process of having them converted to dvd so that the family can enjoy them. Tom

    1. i would like a copy of the movies if by chance you made extras. i would like any photos/ info on these can can email me at. what kind of price might you have in mind?

  4. Is that Tom Ellis of ISDT fame & m/c shop in Ripon?
    In a roundabout way l ended up with the Sll Inter eng, g'box & carbs from one of the Sliger/Enz single engined m/cs, & a year or so later, met the person who'd ended up with it's frame, and very kindly let me have it for a modest sum.
    I eventually rebuilt it with replacement cycle parts, so it doesn't look as original. Had to straighten the frame, rebuild the wrecked gearbox, rebuild the engine with new barrels & pistons, etc etc. Yet to sprint it. One day.
    "Series Ib"



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