PROJECT DRAG BIKE

PART 5: FIT­TED LOOM LIFTS THE GLOOM

Practical Sportsbikes (UK) - - Contents - Words: Gary Hurd & Alan See­ley |

Wiring un­der­way at last and air shift plumb­ing too. Re­ally? Yes

Bird’s nest of wires emerges from Lidl bag and the Big G gets to grips with electrics. Al wres­tles with the pink flo­ral shears. Chris, from across the road, gen­tly de­spairs

Some­times quickly, some­times slowly. That’s how we roll when it comes to projects on Prac­ti­cal Sports­bikes. Al­though when we do get down to it a lot tends to hap­pen very quickly. Project Drag Bike has suf­fered from the mis­ap­pre­hen­sion that be­cause it’s a sim­pler build than a road bike, it re­quires less time. And Drag Bike doesn’t al­ways get the love it should. Not that we’re not al­ways think­ing about it.

Another thing we’ve been think­ing about is the pend­ing win­dow for en­tries for the Brighton Speed Tri­als. The event it­self isn’t un­til Septem­ber but en­tries open for only a brief pe­riod from May. The Vin­tage Mo­tor Cy­cle Club in­vites only 60 bikes to take part and we re­ally want to be one of them. To that end we bet­ter have some­thing to show them and soon. To the shed, Big G and see what you have gath­ered with your mag­pie ways.

The Grumpy One pulls a pretty com­plete wiring loom out of a car­rier bag, like Lidl have just started do­ing big electrics. “This,” he de­clares, “should go on al­right. It’s a GSX-R750K loom.” It says some­thing about the in­ter­change­abil­ity of all things Suzuki of a cer­tain era that the GSX-R loom will hap­pily link ev­ery­thing we need to run our 1200 Ban­dit mo­tor fit­ted onto a GSX1100 frame. All the more sur­pris­ing, to me at least, is that we will be us­ing the 750 ECU that’s still at­tached to the loom. “It does have a slightly higher rev limit but you won’t be over-revving now, will you?” asks G with an ad­mon­i­tory look. He ob­vi­ously re­mem­bers the last time PS rode one of his drag bikes, for­mer fea­tures edi­tor Chris New­big­ging blow­ing G’s GSX1100 into a mil­lion lit­tle pieces [Funny, he never men­tions that – JM]. I sug­gest that I’ll see what I can do about sourc­ing a shift light from some­where. Wouldn’t want to give any guar­an­tees given that any­thing can hap­pen in the heat of com­pe­ti­tion.

“Any­how, let’s get it on the bike,” he says, lay­ing it along the frame. Gary pulls a pair of used Dyna coils out of a box and lays them along­side their tabs on the frame. These give him a start­ing point for the fit­ted po­si­tion of the loom. He wres­tles the head­lamp wiring around the head­stock and tucks it into the bot­tom of the bowl. We still har­bour some no­tion that Project Drag Bike will be eas­ily con­vert­ible for road use.

A new pack of ca­ble ties is rapidly de­pleted as G weaves the loom to the frame. With ev­ery­thing

“THE AIR-SHIFTER WILL BE AC­TI­VATED BY THE HORN BUT­TON, A PAR­TIC­U­LARLY APPEALLING FEA­TURE – BEEP, BEEP, COM­ING THROUGH”

for­ward of the back of the en­gine tied down, we can see the prob­lem we re­ally want to ad­dress; there’s a bird’s-nest of ca­bling with the CDI, fuse box and a va­ri­ety of re­lays plugged into it. This lit­tle lot we have de­cided to ar­range on fab­ri­cated alu­minium plates above the bat­tery box, which it­self sits deep in the chas­sis, more or less where a damper would sit on a monoshock bike.

We elect to ap­proach the mak­ing of the plates for the elec­tri­cal com­po­nents in time-hon­oured fash­ion, first cut­ting some card­board tem­plates. There are many use­ful things in Big G’s work­shop, but a pair of scis­sors does not num­ber among them. He heads in­doors to bor­row some from his other half, Jacki. He re­turns with a pair of bright pink flo­ral shears. By now I’ve learned that it’s best to say noth­ing…

With the tem­plates made the next log­i­cal stage is to break out the alu­minium sheet but with ‘the en­gi­neer­ing de­part­ment’ lo­cated over the road in the form of the long-suf­fer­ing Chris Whit­worth, Gary prefers to get him to knock them up in­stead.

That frees us up to look at the in­stal­la­tion of the MRE air-shifter. There’s a small amount of plumb­ing in­volved in this plus we’ll have to mount up a recharge­able gas bot­tle so it can do its thing. When it was on Gary’s Katana, a mini 12-volt com­pres­sor charged the reser­voir. The air-shifter will be ac­ti­vated by the horn but­ton, a par­tic­u­larly ap­peal­ing fea­ture – beep, beep com­ing through. I think we should leave the horn in cir­cuit, af­ter all we still have the wiring for it.

We still have a few things to sort out. A re­mov­able sub­frame will plug into the main rails to pro­vide a back­stop for the one-piece body­work. We need to or­gan­ise some kind of fuel cell. A pair of very short shocks will be re­quired to keep the bike low. All this and we still have no idea whether or not the en­gine is any good. Still, we do have a spare or two and some­times you just have to take things on faith…

Gary never uses six ca­ble ties when six hun­dred and sixty six will do. As long as he’s not pay­ing for them

GSX-R750 ECU with higher rev limit to be grafted in

And in goes the 750 ECU (with a bit of gen­tle en­cour­age­ment)

Pic­tures: Alan See­ley

Plumb­ing is crit­cal on any bike, dou­bly so on any com­pe­ti­tion tool

He likes pulling his wire does our Gary

Shame to ruin a per­fectly good card­board box

Good to see the gen­der-non-spe­cific scis­sors out

Air for the air-shifter will live un­der­neath the carbs

Horn not what it says on the but­ton any more

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