FIVE into FOUR

In re­cent years, Royal En­field swapped from an old-fash­ioned four­speed gear­box to a newer unit with five ra­tios. Fol­low­ing their ex­am­ple, Stephen Her­bert in­ves­ti­gates whether five into four re­ally will fit…

Real Classic - - What Lies Within - Pho­tos by Stephen Her­bert

In re­cent years, Royal En­field swapped from an old-fash­ioned four-speed gear­box to a newer unit with five ra­tios. Fol­low­ing their ex­am­ple, Stephen Her­bert in­ves­ti­gates whether five into four re­ally will fit ...

Rusty is my 1993 Royal En­field Bul­let 350 Su­per­star. He graced these pages be­fore, back when he was gen­uinely rusty be­fore the re­build. The name stuck and I got on with rid­ing him. All was well, but prob­lems with the gear­box soon sur­faced. These old Al­bion-de­rived In­dian boxes are well known for false neu­trals, jump­ing out of gear, leak­ing lu­bri­cant, etc. I had all of this and de­spite a few goes at sort­ing it, the prob­lems re­mained and it was be­com­ing more of a chore to ride Rusty. Which was a prob­lem cos Rusty is in­her­ently a nice bike to ride. Time to do some­thing more rad­i­cal, then.

The no­tion that ‘five into four’ does go sounds like a pri­mary school arith­metic les­son from the 1960s. Ac­tu­ally it is all about a trans­plant – re­plac­ing the 4-speed Al­bion box with a 5-speeder from a more mod­ern In­dian Bul­let. In this case, a used box from (I think) a 2003 Bul­let 65 sourced from Hitch­cocks. This was orig­i­nally a left-foot changer but a sim­ple mod swaps it to a right-footer. The ac­tion is bet­ter too, as the left-foot ar­range­ment in­volved a long spindly rod pass­ing through the crankcases, oil tank and pri­mary chain­case to emerge on the left.

This in­stal­ment de­scribes how I did the trans­plant. Next month, I’ll ex­plain why, and what it’s like to ride with the five-speed box fit­ted. The next thing about swap­ping gear­boxes with En­field’s pre-unit de­sign is that you can leave the en­gine in situ, to­gether with all the at­tached stuff like car­bu­ret­tor, ca­bles, wires and zorst, and just swap out the gear­box. In fact Roy, my brother-in-law, asked ‘is it just: un­bolt, line up new one and bolt in place?’

Nearly!

Right: This is the new five-speed gear­box ready to be fit­ted. Bought used from Hitch­cocks, sprocket changed and some paint ap­plied

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