Saturday, April 18, 2015

Custom Royal Enfield long-distance trials bike

This neat and rugged Royal Enfield is named Troglobike.
Last summer, Graham Lampkin rode a 1959 Royal Enfield from his home in Colne, Lancashire across England and Scotland — as much as possible off paved roads — to raise money for Cancer Research UK.

He's not done riding yet.

"I was so inspired by last year's trip to Lerwick that I’ve built a bike for such trips and long distance trials," he writes.

Here's his description of how it came about:

I bought a collection of three partly dismantled bikes plus other bits. I didn’t need them, but couldn't say no (I’m sure you understand — not sure my wife does, but if it keeps me quiet).

I had sold a bike in the spring to make more room in the garage, but now of course it was full again. So I sold anything I wasn't interested in etc., recouped the outlay, but realized I had nearly enough to build a bike.

So Troglobike was conceived in my brain. The specification was:

A. Pre-unit single,

B. As light as possible,

C. Usable and reliable before authentic.

The components used are:

Engine. I had an early Redditch Enfield 350cc, but having decided to fit Electrix World electronic ignition with lighting coils I discovered it was difficult to site where the magneto had been; better to put it on the end of the crankshaft. This meant the longer alternator crank, so my engine wasn't suitable. I bought a later Redditch engine but didn't feel comfortable about it. That's when I took a chance on eBay ('cos the price was right!). This was a 1977 Indian 350 and a piece of luck. When I collected it from the vendor, he told me he knew very little about it except that he bought it in auction from the personal effects of a previous employee of Redditch who had died. First impressions backed this up. I've fitted an alloy barrel but the rest of the engine appears to have been competently rebuilt; it runs well.

Ignition. With a lot of work the Electrix World unit has been fitted to the end of the drive side crankshaft, enclosed in a narrow inner chaincase and a matching outer with a small alternator bulge (thanks Andy).

Gearbox. Wasn't sure what to do; the Enfield box doesn't have the best of change mechanism and I did have an AMC road ratio box which I’m told would fit with some work and jiggery pokey. Then the Indian 5-speed was recommended. When I researched this I found the overall spread of ratios was exactly the same as the 4-speed trials box but with a better action and spread over five gears. Best of all it fits straight on with the kit Hitchcocks supply with it. No contest, Indian 5 speed was ordered.

Clutch. Standard fits straight on with a new clutch center, but they don’t tell you you need a four plate version and I had a three plate, just one of several two steps forward, one back experiences.

Frame. Royal Enfield Crusader that was in the collection of bits. They are a good frame, light and good geometry, and with a little alteration take a Bullet engine. I even had some laser cut engine plates left over from a previous project (thanks Owen). More good news is that the Bullet engine fits easier with the 5-speed gearbox than the 4-speed.

But let's start from the beginning. Any lugs etc. that are known to not be wanted are removed as the frame is stripped. A slightly longer swinging arm (from a MZ – slightly longer and I had it!) made ready. The seat area needs pulling in by 15/20mm per side. The steering head bracing tube is cut, bent up to the top tube and welded to it. Stud fitted behind the steering head ready for the petrol tank

Wheel and forks etc. all came from a Honda XL350 – good quality and lighter (thanks again Andy). I altered a pair of alloy Beta yokes to replace the Triumph ones supplied and fitted by A.N.Other (as seen in the photo). They suited better and just needed a new stem making.

Petrol tank and seat. I had these made for the Lerwick trip: tank holds nearly 3 gallons (thanks Roger).

That’s the basic kit. But I’m sure the dear reader would find a blow by blow, nut by bolt description of the build boring (any questions please get in touch). It's more the ethos and design that I'm trying to describe here and that I find interesting.

Finally, why "The Troglobike"? At a club meeting recently a fellow member said every build needs a name and helped me with this (thanks Tony). As I’m sure you dear reader know, during WWII Royal Enfield continued production in an old Bath stone mine, and as you don't know, my garage (where the bike was built) is reminiscent of a cave – does that answer your question?

I now feel confident to continue with the charity riding. The initial planning has started for "Lampy goes to 'L" — not before time say some. This will be in early 2016, more details later. There is a website — — of course the link for donations to Cancer Research UK will remain open.

P.S. a 500cc engine turned up, it's now in the bike!

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