CON­STRUCT A MO­TOR­IZED TRIKE

A CA­SUAL CHAL­LENGE TO BUILD A DRIFT TRIKE LED TO EIGHT MORE AND A SPE­CIAL RALLY

The Shed - - Front Page - By Ian Parkes Pho­to­graphs: Adam Croy

Cam­bridge man Kim Daw­ick knows a thing or two about build­ing drift trikes — he’s built nine of them and no two are ex­actly the same.

His plan was the op­po­site of cre­at­ing a pro­duc­tion line — that would be too bor­ing. He has tweaked the de­sign from build to build, but not through any process of re­fine­ment. The changes were driven by the parts that he had on hand and want­ing to make them look dif­fer­ent. “It just en­cour­ages you to be a bit cre­ative,” he says.

“For me the most im­por­tant thing was just to keep the cost down.” That’s some­thing that many suc­cess­ful cap­i­tal­ists would agree with but Kim’s mo­tives are dif­fer­ent. He was build­ing these for friends, not for profit. And he has no in­ten­tion of build­ing them com­mer­cially.

“I haven’t asked for money for any of them; it’s just for fun — but I didn’t want to throw $5K at it,” he says.

Can you add an en­gine to that?

Kim has a long his­tory of adding en­gines to toys. He has sev­eral mo­tor­ized scoot­ers in his garage, fea­tur­ing out­ra­geous ex­pan­sion cham­bers, the first of which he hot­ted up when he was 19. He worked as a me­chan­i­cal en­gi­neer but has spent

“I haven’t asked for money for any of them; it’s just for fun — but I didn’t want to throw $5K at it”

most of his time as a pro­fes­sional hunter for the De­part­ment of Con­ser­va­tion (DOC). He’s now a struc­tural in­spec­tor for the de­part­ment. Be­ing handy with a welder and a lathe are the most com­plex skills re­quired; the rest is just down to hav­ing the con­fi­dence to give it a go.

The idea for the trikes came up when hav­ing a beer with a cou­ple of mates after see­ing some sim­i­lar home­built drift trikes on YouTube. One of his mates half-jok­ingly prod­ded Kim to build one, so he tucked the idea away, got stuck in and, a few weeks later … “I made him one as a sur­prise for this 40th,” says Kim.

A trike Grand Prix

Now, at this point, Kim had only built one trike, but he has a lot of mates, and all agreed that it would be a lot more fun to race them at their own Grand Prix event. So, nat­u­rally, one of his mates said that he’d ar­range the venue, food, and drink if Kim would build the trikes. “Be care­ful,” said Kim. “I might just do it.”

This idea also took hold. Once Kim had fin­ished the ninth, plan­ning for the event got well un­der way. “I just thought it would be great to get the old crew back to­gether,” says Kim. “We all used to be into cars and do­ing them up, so each bike has a bit of the owner’s per­son­al­ity in there. If you had a yel­low Monaro, you get a yel­low trike.”

Just two of the nine have two-stroke mo­tors, one 50cc and a tid­dler with just 33cc, while the four-strokes use Honda’s 212cc sta­tion­ary en­gines putting out a whop­ping 6.5hp (4.8kW).

None of the trikes is ex­actly the same

as an­other. “They are all like your chil­dren,” says Kim. “You don’t have any favourites — ex­cept you do.”

His own favourite is the titchy twostroke: “No doubt the four-strokes are faster but I just love two-strokes and the fact that even though it’s only 33cc it’s nearly as good as the four-strokes,” he says.

And while the trikes can reach 60kph, and one — mod­i­fied from a pit bike — can top 80kph, speed isn’t the main ob­jec­tive. “It’s all about los­ing trac­tion,” says Kim. “These things are like drift cars on three wheels.”

You will no­tice that their go-kart tyres are fit­ted with plas­tic pipe treads. This en­sures that they have minimal grip and will slide at the slight­est provo­ca­tion. As there’s no dif­fer­en­tial,

“We all used to be into cars and do­ing them up, so each bike has a bit of the owner’s per­son­al­ity in there. If you had a yel­low Monaro, you get a yel­low trike”

you couldn’t turn the trikes with­out their plas­tic over­coats.

“Go-kart tyres are so grippy that you’d just go straight ahead,” says Kim.

The en­thu­si­asm of the su­per-slippy rear wheels for slid­ing also means that Kim and crew have never man­aged to flip one.

“I’ve got no in­ten­tion of build­ing a go-kart that goes where you point it,” he says. “That was al­ways the point — no trac­tion.”

To see what he means, check out his first four-stroke ma­chine and its test run at youtu.be/D9SJC­gr­mESs.

Get­ting more punch from a two-stroke

The two-stroke en­gine in Kim’s trike started out at 33cc but he ported it, got a big­ger carb, and added one of his be­spoke ex­pan­sion-cham­ber ex­hausts. A well-de­signed cham­ber can re­ally turn a two-stroke en­gine into a fire-breath­ing de­mon. Get­ting the right swirl and draw in an ex­pan­sion cham­ber is quite an art, but Kim says that you can get tips on any­thing from the in­ter­net now.

He also bounces ideas off a friend in the US who also likes to add an en­gine to any­thing.

He says the flash­est trike is for his friend Naomi but mostly be­cause he picked up half a go-kart at a swap meet, so it’s got a bet­ter rear axle. The mean­est is his friend Flea’s, which has a pit-bike en­gine mounted be­tween the rider’s legs, and is ca­pa­ble of 80kph. That uses an old moun­tain-bike frame.

An­other trike got the ta­pered bars, head­stock, forks, and front wheel from a fat bike, which also fea­tured a flash disc brake. He cut off the stan­dard head­stock to weld this on.

“It would be ex­pen­sive to do that but I had them left over from an­other project,

and just thought I’d use them to make it more in­ter­est­ing,” he says.

How­ever, Kim has set­tled on a re­li­able for­mula that gives a great re­sult at minimal cost — which is just as im­por­tant to home builders as com­mer­cial suc­cess is to en­trepreneurs.

How to build a drift trike

The ba­sic re­quire­ment is a kid’s trike from The Ware­house or sim­i­lar. Kim finds the model with the curved spine ro­bust enough for the job. The com­plete front end — bars, head­stock, forks, and wheel are also fine, as is the base for the seat. All of Kim’s mates are tall, around 190cm, so for their trikes he welded an ex­ten­sion onto the seat plat­form to move it back, but this may not be nec­es­sary for or­di­nary-sized hu­mans.

The busi­ness end of the trike is the rear axle from a 110cc quad bike. These axles are al­ready the per­fect width, says Kim. They have a flange to bolt the sprocket to. But you have to get new sprock­ets as the gear­ing is wrong. Some have cen­trally placed bear­ing car­ri­ers that sim­plify the job, but oth­ers are off­set to al­low for dif­fer­ent mo­tor de­signs. That means you might have to weld a sec­tion of box steel onto the bike’s cen­tral spine to marry it to an off­set bear­ing car­rier. “It’s sim­ple enough,” says Kim. “It’s all

mild steel and weld­able.”

The wheel hubs also have to be turned down and redrilled so that they can be bolted in­side go-kart rear wheels. The axles come with a disk brake fit­ted, com­plete with calipers and hy­draulics. Some early mod­els had drum brakes. One of Kim’s bikes has that ar­range­ment but the disc brakes are sim­pler and bet­ter, he says. While the trikes have a sim­ple bi­cy­cle-type front brake, they aren’t very strong. The rear brakes — even with the low trac­tion plas­tic treads — work much bet­ter. They are also great for ini­ti­at­ing the skid.

A $20 en­gine score

Kim says the best-value en­gines are the Honda, or Honda-clone, 6.5hp sta­tion­ary en­gines. These un­burstable units are now very pop­u­lar for kids’ go-karts and a whole range of ac­ces­sories has grown up around them. He picked up a brand­new en­gine ad­ver­tised as faulty after it had been re­turned to the ven­dor. At a cost of $20, with an­other $20 for the courier, Kim thought that it would be good for parts. The en­gine wouldn’t turn over — for the sim­ple rea­son that it had been filled to the brim with en­gine oil and was hy­drauli­cally locked. Kim

drained it to the right level and it fired up first time. Per­haps a sec­ond en­gine will also be com­ing on the mar­ket soon, if the pre­vi­ous owner has done the same thing to his re­place­ment en­gine.

If you are plan­ning a build, Kim says that it’s worth writ­ing up a parts list, but it’s a short list. You need the trike, axle, mo­tor, clutch, chain and sprock­ets, wheels and wheel sleeves, twist-grip throt­tle, and throt­tle ca­bles.

“I like to buy ev­ery­thing sec­ond hand and if you are not too fussy what they look like you can get a bar­gain. You could prob­a­bly build the whole thing for $300,” he says. “If you were buy­ing ev­ery­thing new it could cost $800.”

Sourc­ing parts is not hard

Kim tells us that a man in Te Puke im­ports go-karts for parts. A pair of wheel rims usu­ally costs $60 but Kim bought eight at a dis­count. Be­sides go-karts, there’s also an in­dus­try sup­port­ing minibikes or pit bikes, which are an­other source of cool-look­ing after­mar­ket parts, such as air cleaners and ex­hausts.

He scours in­ter­net trad­ing fo­rums and swap meets for sec­ond-hand parts. If you want to get straight into it, lo­cal sup­pli­ers like Storm Parts of­fer good ser­vice for things like sprock­ets and chains, and they can of­fer overnight de­liv­ery.

Kim says the best place to start is with a donor 110cc quad bike. He says they get left out­side and go rusty and will of­ten be ad­ver­tised at a $1 re­serve. “You can gen­er­ally get them for less than $50.”

The main part you want is the axle but if you get the com­plete quad you also get the brakes, mas­ter cylin­der, and lever too. Usu­ally the mo­tor won’t work, but if you can get it go­ing again it makes life sim­ple. “That’s what Flea’s bike is — the mo­tor worked,” says Kim, “and if you only get the axle and brakes it’s still a good deal.”

You don’t need a whole quad bike — Kim says that you can pick up the rear­axle assem­bly alone, with no brakes or calipers, rel­a­tively eas­ily on in­ter­net sale sites for just $65. After all, he has found nine of them, all told.

“Even so, parts are pretty com­mon, so you could get a disc ro­tor for $10 or the sprocket for $20 or $30,” he says.

Kim ex­plains that the sprock­ets you need for the 6.5hp trike are a 72-tooth rear and an 11-tooth front with a pitch of 35. You also need a cen­trifu­gal clutch for a ¾-inch splined drive­shaft and

the 35-pitch chain. The drive­shaft is threaded, so you need to fin­ish it off with a bolt and washer to stop the clutch walk­ing off the shaft.

In­stalling the power plant

The next step is to marry up the mo­tor to the frame where it will align with the sprocket on the axle. Kim says that with the last five trikes he sim­ply welded a box­sec­tion frame to the rear of the car­rier. He bolted the en­gine to a mount­ing plate and slid that along the box-sec­tion frame un­til the chain came tight. He marked it and welded the mount­ing plate in place. He says that you could cut slots in it to make it eas­ier to ad­just the chain later but “the lazy way” of adding wash­ers to the mount­ing bolts to raise the en­gine worked just as well.

An­other thing to make sure of is that you in­stall some kind of chain guard so that if the chain breaks it doesn’t flail for­ward and hit the driver.

Kim de­signed and made his own ex­haust pipes and even some muf­flers. That’s half the fun of it. He was keen to get va­ri­ety in the field, so looks were im­por­tant.

Some of Kim’s bikes fea­ture BMX pegs in­stead of ped­als, but Kim says that’s just on the bikes that had stan­dard or mo­tor­bike front wheels, which don’t have ped­als. The trike front end has ped­als on a free­wheel hub, and they make per­fectly fine footrests. Kim says there is no point chang­ing them.

He says that you could weld bolts onto the forks for BMX pegs but you wouldn’t be able to use the axle in the free­wheel hub, so he rea­soned that it wasn’t worth it: “You can rest your feet on the stan­dard ped­als and it’s ab­so­lutely no prob­lem.”

Some unique touches

Stan­dard plas­tic tanks look a bit or­di­nary so on sev­eral bikes Kim re­placed these with old fire ex­tin­guish­ers painted and la­belled to look like ni­trous-ox­ide tanks. He made brack­ets and car­ri­ers to hold them at dra­matic an­gles. So cool.

One of the essen­tials of the drift trike is the plas­tic rear-wheel sleeve. Kim had some cul­vert pipe of just the right size handy but says it’s hard to come by. The stan­dard item is Humes stormwa­ter pipe with an in­ter­nal di­am­e­ter of 259mm. It’s avail­able in 6m lengths for about $500 but it’s also avail­able pre-cut in the 130mm widths needed for tyres at $90 for the pair.

“It’s easy to in­stall. It’s just a mat­ter of let­ting down the tyre, slip­ping it over by hand, and then re-in­flat­ing the tyre, which holds it firmly in place,” he ex­plains.

Kim bought the sets of sleeves as he had not set out to build nine bikes, but says you might want to con­sider the 6m length, as hav­ing just one trike is never enough.

“We had sev­eral guys who like their ma­cho cars or trucks and were re­luc­tant at first, but even­tu­ally they’d give in and then you could never get them off them,” says Kim.

Build­ing drift trikes is only the start of the fun.

A beau­ti­fully or­ga­nized shed made it eas­ier for Kim to keep nine trikes on track

Above: When Kim ac­cepted the chal­lenge to build nine trikes, keep­ing the costs down was vi­tal to a suc­cess­ful out­comeLeft: Now to put it all to­getherBe­low: Weld a bike frame to a quad bike rear-axle bear­ing car­rier and you have the bare bones of a trike

Adding mo­tors to things gen­er­ally makes them more in­ter­est­ing for Kim. He built a school trol­ley derby en­try for his nineyear-old daugh­ter that he de­signed to look like a go-kart. She came sec­ond in the race at school but Kim soon got bored with push­ing it up the drive at home so added a mo­tor to turn it into a real go-kart

This is Gubby’s four-stroke en­gine and even though these en­gines are faster, Kim loves twostrokes be­cause al­though they have pint-sized cylin­ders in com­par­i­son, they are nearly as good as the four-strokes

Kim tweaked the de­sign from build to build, with changes driven by the parts that he had on hand and could adapt

The ni­trous look

These trikes are made to drift; no grip or trac­tion re­quired here, thanks

Kim has also flirted with fur­ni­ture­mak­ing. One of his ear­li­est pieces is a chair that he made for his fu­ture wife, as you do, which com­bined his me­tal­work and wood-work­ing skills. As his wife is into art, at his brother’s sug­ges­tion he turned what was go­ing to be a plain seat into an artist’s pal­ette. Kim has also built some nifty wooden units for stor­ing ban­gles and neck­laces, a TV stand in­spired by ap­ple boxes, and a 40m fly­ing fox for his three chil­dren on their place out­side of Cam­bridge. Kim’s time in the shed works for all the fam­ily

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