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Evolution of the Purple Prayer

Posted: Mon Jan 15, 2018 9:58 pm
by DuncanV
Back in 2005 I had the good fortune to win a KTM 640LC in a national competition which was awesome but it meant that only myself could enjoy the pleasures of hooning round the countryside, this seemed a bit unfair on the rest of the family. So, a well intentioned relative said, why not built a trike that my wife and then 13 and 15 year old daughters could come out on. Great idea. He had been looking through the local papers and spotted a GL1000 going for about £500 so we arranged a viewing. When we arrived, there were two bikes and we could take our pick. The first was quite tidy and un-messed with but the second had been tied to a chair and had leading link front forks and had been fairly extensively ‘customised’ by the owner as the first picture showed. Condition-wise it was a bit tatty with blowing exhausts, manky seat and crap paint, a good starting point to make a silly offer which after a bit of haggling a price was agreed. It was trailered home where it sat for 18 months while I thought about it.
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I decided on the criteria for a design after looking on countless sites and examining professional and amateur build alike. I came up with a sort list of essential features:-
It had to have 3 seats.
It would be as short as possible (not much longer than the original bike)
It would be below 400kg (for bike trike regulations)
It would be a bolt-on sub-frame so I could keep the original registration
It would use a Reliant axle.
This decided, I searched E-bay for a suitable axle and found one, complete with 3 alloy wheels for £95, and good deal, even though it was is Scotland. I had researched axle ratios and found that Reliant did a 3.32:1 which is very close to the GL1000 at 3.44:1 and this allowed me to use smaller car wheels. I also looked at rear brake conversions and opted for VW Golf GTi calipers and Nissan Sunny discs which spaced out nicely with the 10mm alloy carriers I made.
Time to strip the donor bike to a degree that I could place the axle and start designing the subframe. I mounted the bike level and steady on chocks and placed the axle on the garage floor in the approximate position I wanted it.
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Being a woodwork/metalwork teacher, I always advocated pupils making mock-up or models before starting the real thing so out came the MDF sheet and plastic pipe to start the job. The axle was locked to the rear footrest mounts so the geometry would always be the same during the build and I opted for a 5 link suspension with a Panhard rod.

Re: Evolution of the Purple Prayer

Posted: Mon Jan 15, 2018 10:03 pm
by DuncanV
Being a woodwork/metalwork teacher, I always advocated pupils making mock-up or models before starting the real thing so out came the MDF sheet and plastic pipe to start the job. The axle was locked to the rear footrest mounts so the geometry would always be the same during the build and I opted for a 5 link suspension with a Panhard rod.
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After several design alterations (which were easy because I was using plastic) I settled for the one shown but added curved links between the lower front loop and the rear verticals. The whole plot was bolted to the original frame at 8 points and even built from plastic and wood, it was strong enough for me to stand on and jump about. I took measurements, drawings and MDF patterns do to a local metal fab shop and they bent and cut the main frame tubes and plates.

Re: Evolution of the Purple Prayer

Posted: Mon Jan 15, 2018 10:07 pm
by DuncanV
More pictures of the mock-up
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Re: Evolution of the Purple Prayer

Posted: Mon Jan 15, 2018 10:10 pm
by DuncanV
These were brought home and set up in place of the plastic and wood and attached to the frame. I then tacked them together with a MIG before taking it back to the fab shop where they welded it all together. I wanted this done professionally for safety because I am more of a melter than a welder!!
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Re: Evolution of the Purple Prayer

Posted: Mon Jan 15, 2018 10:14 pm
by DuncanV
I bent the seat supports and any extra brackets for exhausts and lights etc, Little details like seat belt mounts are easily forgotten so it is worth doing a complete ‘dry’ build before finalising it. You will possible notice that he Panhard rod mount needed to be strengthened, the lights have changed and a towbar have been added. The axle was mounted using block claps and an alloy plate cut to take the top diff tie rod. The USA provided very useful tapered and threaded pipe inserts for making up the link arms and the local bearing trader stocked the threaded eye joints.
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Had to have a 12 month break here to build a house extension, hence the mixer in the pictures and the various building materials laid about.

Re: Evolution of the Purple Prayer

Posted: Mon Jan 15, 2018 10:17 pm
by DuncanV
I always looked at trike exhausts and found them trailing on the ground or being very poorly done so I wanted a good looking system. Fortunately, many HD owner junk the original silencers for something louder so I picked up a virtually brand new set for £20 on Fleabay. A local exhaust maker called Pickering Performance made a superb job on the link pipes for not a lot of money (Thanks Kev).
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Re: Evolution of the Purple Prayer

Posted: Mon Jan 15, 2018 10:19 pm
by DuncanV
Next was the bodywork and it was out with the cardboard sheets, scissors and tape until the best solution was found. These were then cut from 18swg galvanised sheet before going to the sheet metal shop (Aycliffe Fabrications) for a really near weld job. Siting the handbrake can be a problem on trikes and I’ve seen some really weird contraptions but this was quite easy using a Mini lever and quadrant and a home-made link to connect two cables to. The new prop shaft was measured up and the two parts cut to length before welding and balancing (Major & Aspinall in Durham £30). I used the air shocks that came with the bike at first but one had a chronic leak and the whole plot would sag drunkenly like a bad dream after leaving it overnight. These were replaced by excellent Hagon units on final assembly.
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The whole lot was rolling now and I chuffed round the local carpark with the blowing exhausts farting like a bum on Thunderbird. It went in a straight line and steered and stopped on front brakes only. [attachment=1]Trike1 (79).JPG
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Re: Evolution of the Purple Prayer

Posted: Mon Jan 15, 2018 10:23 pm
by DuncanV
Back inside, I made wooden seats and backrests, sorted out the original wiring which was like a snakes wedding party and added the extra loom for the rear lights etc. The whole bike was then stripped for powder coating, paint and polishing. All the black parts, frames, brackets, axle and forks went for blasting and powder coating (Impreziv Finishing in Darlington) 60+ parts and wheels for £300 (Thanks Mark). I cut down the K&Q seat earlier on and didn’t know what to do with it until someone suggested Shaun at Demon Seats in Shildon. I gave him the front half of the seat pan and he did such an amazing job on the upholstery that I asked him to do the bench seat and backrests which he did for £120. I wanted to go different on the rear lights so I mapped out an LED display in the shape of hands and used big LEDs which were new to the market at the time. The engine was running fine with good compression and no smoke so I cleaned and polished it, serviced it and changed the belts. I needed a new rad and some tin parts which came from the USA before postage prices got silly. The carbs were stripped and checked and cleaned but more about them later.
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Re: Evolution of the Purple Prayer

Posted: Mon Jan 15, 2018 10:26 pm
by DuncanV
In all the photographs in the last post and from this point on, the paintwork appears blue but it is in fact purple, I don’t know why, maybe it is a trick of the light but it was impossible to get the pictures correct but a very,very small alteration in Photoshop to alter the colour balance to the correct hue.
I am particularly proud of the metallic paint which I did myself using a Papa Roth dry flake gun. After priming and base coat, I sprayed a coat of lacquer and while it was still wet used this amazing little flake gun to spray the dry flake on. It can be smoothed with a latex glove and any bald patches gone over again to make it even. I then sprayed with 2 pack lacquer and it only took about 7 coats to bury the flake instead of the usual 10-12 coats and you don’t get your gun clogged up with flake for ever and a day. I rubbed it down with 1200 wet or dry and polished with a rotary mop.
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Re: Evolution of the Purple Prayer

Posted: Mon Jan 15, 2018 10:28 pm
by DuncanV
Assembly continued and some old parts didn’t cut the mustard and needed replacing, exhaust headers, ignition switch, headlight, indicators, brake lines to name but a few. All fastenings were new stainless because nothing lets a project down more than rusty nuts and bolts.
All finished and trailed it down for its first test which it flew through and so insurance and tax and ready for the road.
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Re: Evolution of the Purple Prayer

Posted: Mon Jan 15, 2018 10:30 pm
by DuncanV
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I had never ridden a trike before and as I took it, helmetless, up a local country lane, I thought what a Frankenstein monster this was, I rattled, shook, hit every pot-hole in the road and seemed to try and throw me off at the earliest opportunity. My eyes were streaming from the wind blast and it wasn’t the pleasant experience I was expecting but I returned home with a big grin and dribble down my chin!! It was horrible to steer round corners and it seemed like all the wheels wanted to go in different directions. I changed the shocks for Hagons and it improved and a local friend who competes in hill-climbs spotted a problem. He suggested an anti-roll bar so after searching the local breakers, I found one from a Ford Focus and fitted it by welding mounts on the rear frame loop and it transformed the handling. I had rebuilt the original rear master cylinder but it caused a problem by locking the rear brakes up. I thought it was losing power but when I stopped and the rear pads were smoking there had to be a problem. It was the tiny 1/2mm spooge hole that allows the fluid to return to the reservoir that was blocked and it took ages to find. More recently I had to replace the master cylinder with 5/8 or14mm bore one from China. It has improved things immensely. I am in the middle of converting it to a single twin-choke Weber at the moment and as my other thread will show, I am still seeking advice.
Please feel free to ask anything that is not clear or if you want me to take some detail pictures, many thanks for indulging me in this rant and I hope you find some of it interesting!

Re: Evolution of the Purple Prayer

Posted: Mon Jan 15, 2018 10:54 pm
by duke182
Nice

Re: Evolution of the Purple Prayer

Posted: Mon Jan 15, 2018 10:58 pm
by gltriker
tumb2 Nice job, Duncan!

What gear ratio is the rear axle assembly?
What is the diameter of the rear tires? Tyres?
How much does the total vehicle weigh?

Re: Evolution of the Purple Prayer

Posted: Tue Jan 16, 2018 1:52 am
by HOTT
That came out great!
Rear signals are very clever. tumb2

HOTT

Re: Evolution of the Purple Prayer

Posted: Tue Jan 16, 2018 8:22 am
by CYBORG
Excellent job, and excellent explanation or how you did it.