Yamaha YZF750 Cadburys Boost Replica

15/03/10 marks the arrival of project 'Cadburys Boost YZF750 Replica'.
Those of you old enough will remember the iconic 90's superbikes raced by the likes of Niall Mackenzie, Jamie Whitam, Chris Walker and Steve Hislop.
The plan is to build a reasonably accurate replica (visually) with a daytime MOT for the pitiful use it will invariably get.
And it's being built to a budget, just because its the shop's bike don't think it will be a no expense spared exercise, oh no, the accountant (or wife) would never let me get away with that!

21/03/10 Bike is now partially stripped and to my surprise didn't throw up any horrors (early days yet though). A quick oil change and it seems to run ok with just a slightly erratic idle which will be investigated later.
A full set of race fairings have been ordered from BB Plastics and an Ebay swing arm and rear shock are on their way.
24/03/10 Currently having difficulty finding images of the original bikes so there may be a bit of 'reinterpretation' taking place...

30/03/10 Much time has been spent pondering and waiting for the fairings to arrive, but not a lot has actually been achieved...
Ebay shock and swing arm have arrived and the arm is now with Alan at GTS Motorcycles where he is working his alloy welding magic on it. Hopefully it should look a little bit like the 'kit' swing arm the race bikes used. If it doesn't it will at least look different!
Search is on for a smaller rear calliper and a way to mount it to replace the gigantic ship anchor it currently uses. Front and rear discs are the same as used on most Ducati so a solution could come from that direction...

21/04/10 A long period of inactivity has taken place. Many jobs that could have been started and finished by now have been in a holding pattern on my to do list (as a result of volcanic dust I imagine)Fairings arrived and were still in one piece (never watch the delivery driver unloading his van). Pleasantly they seem to be better quality than many I have seen in the past. At ?245 for the kit, they were not the cheapest available but it is reflected in the quality. The belly pan came fitted with quick release fasteners and all the mounting points have pilot holes drilled.

22/04/10 In what can only be described as child like naivet?I thought I would do a quick trial fit of the fairings.
Much huffing and cursing ensued. After about 30 minutes I had decided to put the bike back together and sell it on ebay.
But after a short sulk and some encouraging words from the wife I went back to the garage where patience won an unexpected victory over my short attention span.
So the fairings are on but I will need to set aside a chunk of time to get them fitting perfectly. Hopefully this will entail some tweaking of mounting points and enlarging of mounting holes, and not another temper tantrum.

25/04/10 To be fair all that was required was a bit of patience and the fairings now fit reasonably well.
An undertray was ordered from Poland (only place i could find one) and will need some work to get it fitting properly.
Now the part I enjoy right up to the point of actually doing it, painting. The primer went on without any mishaps as I had decided, unusually, to take my time and paint one panel at a time. This means I can actually see and walk around the part I'm working on in the limited space I have. Although this means it takes longer and there's more cleanup, it also means I only have to paint things the once!

27/04/10 Man walks in to a paint shop...
So off I trot to the local paint emporium brandishing my mint copy of BIKE magazine circa 1997 (ebay). I show the man behind the counter the photos of the original Boost bikes and ask if he has that colour purple.

What's the paint code (he reasonably asks)
Erm... I don't know
Well I'm afraid you'll have to do some more research and come back
It doesn't have to be spot on, just purple
He hands me some paint chips to look through and goes to look on his PC
After much um'ing and ah'ing I think I have settled on a shade when he returns from the PC
Could this be it?
What's it called?
Cadburys Purple
Yeah, that'll be it.

13/05/10 Front mudguard now finished and ready for decals and lacquer. Oh no it isn't, it's FALLEN ON THE FLOOR and needs to be flatted down to bare plastic and started again...
This is not the exact purple as it seems to come out blue when photographed so this image has been tweeked in photoshop. The actual colour is very nice though.

16/05/10 Fairings temporarily fitted to make laying out the stripes 'easier'... still took the best part of the day though, getting all the lines to follow through and be identical on both sides. Fortunately you can't look at both sides of the bike at the same time!
In typical fashion a short cut with the previously dropped front mudguard was attempted. If history teaches us anything it's that I don't learn from my mistakes. A quick flat down and a blast of Cadbury's finest purple resulted in a couple of paint reactions and a nice big run. The mudguard which now weighs twice its original weight will be taken back down to bare plastic and started again. Probably.

18/05/10 The hours spent patiently masking have actually paid off for a change and the seat unit looks as intended. I have ordered a new type of lacquer that I've not used before so there is still potential for more tears and tantrums.
Plus a small chip has appeared from nowhere (honest, it wasn't me guv), in what will inevitably turn out to be an impossible spot to repair without starting all over. Hopefully the seat is not in cahoots with the front mudguard which refuses to be painted...

21/05/10 Peeling off the masking felt like a plastic surgeon removing bandages... except obviously they don't find bits of white and gold overspray where the masking has lifted (at least I hope they don't). Fortunately there's plenty of purple on there so it should all flat out ok.
This is the first time I've done intricate (for me) masking and colour overlays and I'm quite pleased with the results. Next up is a trial fit and measure up for all the logos.

27/05/10 The undertray will need a fair bit of work to fit well. It survived its trip all the way from Poland in a flimsy cardboard box unscathed which proves it's substantial construction but fit and finish are not up to much.
As the bike will rarely have a number plate fitted I have cut out the number plate mount and filled the hole, and the front end has been trimmed down and re-profiled as it hung too low under the bike. Note to self, don't wear shorts and t-shirt when working with fibreglass. Still itching.
Lurking in the background is the front mudguard (he who refuses to be painted) which, since flatting down again, has fallen over twice...

11/06/10 The sudden arrival of summer, albeit briefly, has meant weekends have been spent riding my other bike (which I am unable to divulge due to loss of credibility. Those who know what it is will no doubt agree), so the project has stagnated. Again. However most of the decals have arrived and I have managed to finish all the purple (except for the wheels). Even the front mudguard is painted and waiting for lacquer.
This being my birthday weekend means little will be achieved. And yes thank you, I know I don't look a day over 21.

23/06/10 Progress has been truly snail like, due to the pleasant change in weather and a sudden lack of enthusiasm.
What looks like a nice shiny finished seat unit is in fact full of 'fish eyes' and a yellow tinge on the white areas. As I suspected and having just spoken to the very knowledgeable lady at RS Paint (where the 2k lacquer is from), both of these issues are of my own doing... The 'fish eyes' caused by applying 2 coats too soon and the yellowing due to too heavy a coat. Unfortunately it wasn't possible to sand out just the lacquer, and as much as I am tempted to do some sort of 'repair' job I think the only real solution is to start again from scratch. And yes, of course the front mudguard has suffered the same fate. Drat and double drat!

14/07/10 The seat unit and front mudguard have beaten me. What little enthusiasm I had left has deserted me.
This is how the bike stands now and how it may well stay... If anyone is interested in a half finished project drop me an email. Comes complete with all original parts.

27/07/10 The ebay gods have decreed that the project must continue. Well, continue or sell it for 10p to some numpty on ebay.
I hadn't realised that anyone was actually reading this, so my spirit was lifted after I received a few encouraging emails (cheers guys). So it looks like the love hate relationship is set to continue. However as the bike has obviously missed its summer debut, I think forward progress will be at my more my usual sloth like pace.
Work has re-commenced on the evil seat unit, watch this space...

01/08/10 Progress at last, the tank is now lacquered!

19/08/10 Yet more progress, we're flying now... well, at least one step forward after 10 steps backwards anyway.
A coat of rather attractive barcoat (isolator) seems to have finally put an end to the paint reactions that were killing the progress and my enthusiasm. With any luck we may be back to purple tomorrow, i.e where we were 3 months ago.

1/09/10 Seat unit is finally repainted. It also gave me the opportunity to run the gold stripe at a better angle as I had previously forced it to run lower than the natural line (because that was where I wanted it), but I think this looks better.

There are more decals to go on but these will go over the lacquer so they can be changed when the whim takes me.

3/09/10 After all the previous issues with the lacquer I was not looking forward to painting the fairings one bit. I decided to go for one heavy coat to avoid any yellowing or fish eyes, as starting over from scratch just wasn't an option.
The result is they look like I just poured the paint over them, there are that many runs! Obviously, thinking about it now the lacquer is going to adhere to the painted surfaces at a different rate than the vinyl graphics... This shouldn't be a problem as they should all flat out and polish up.

13/09/10 Apart from a few more stickers and a final polish the bodywork is done! A general lack of enthusiasm (seemed like a good idea at the time) has meant I'm about 3 months behind schedule and probably only half way through the build. The rest of the build is mainly mechanical, which I enjoy, so things could speed up. However the rest of the build is also going to be expensive, so things could also slow down...
Jobs left to do; Polish frame/swingarm, paint wheels, strip forks, rebuild brakes, sort exhaust, find-modify-rear brake, clipon's, rear sets, seat cover, new discs, chain etc etc etc.

20/09/10 Bodywork is in its new home for the rest of the build, on the spare bed (sorry Jan).
Forks are stripped and need to be anodised gold. If anyone knows where I can get this done locally please let me know.
Probably could do with some new head bearings while I'm here as these seem very notchy. I also need to decide if I'm going to ditch the exhaust, I'd like to leave it to keep costs down but now would seem like a good time to change it if I'm going to...

11/10/10 Forks anodised gold by a local company (Corodine) for ?40! What an absolute bargain and only took a couple of days. Not sure if the shade of gold is correct as 'fake Ohlins' wasn't listed but they look much better than before.
Fork bottoms painted aluminium silver so all I need now is some, ahem, Ohlins stickers and the transformation is complete! Just need to reassemble with new bushes, seals and oil.

13/10/10 Frame polishing has commenced. First strip off lacquer with varnish removing wheel, then flat using decreasing grades of wet or dry. Then polish using decreasing grades of compound and mop.
Sounds simple when you say it like that. It isn't. It's time consuming, back breaking, dirty work. 2 hours to do a 50cm section and I'm not happy with the finish, I think it needs more flatting first. Groan.

21/10/10 Frame polished (just the main spars, too much effort to do all of it, plus I think it was like that on the race bike) and forks fitted with cleaned up yokes and new head bearings.
Just some cleaning of ancillary brackets and hoses to tidy things up.

25/10/10 Rearsets for the Suzuki Hayabussa seemed to be the closest match with the mounting holes only being about 3mm out. So a pair of Thailand's finest were ordered from ebay. Their not Harris or Arrow quality but for about a quarter of the price... The mounting plates were cut out to allow for the notch in the frame and the lower mounting position modified slightly and voila!
Pegs are about 45mm higher and further back but I won't know if this requires double joints until I get the seat and bars back on.
Oh, and the standard rear brake master cylinder no longer fits (obviously) so I need to change the way it mounts or find an alternative cylinder.

12/11/10 Fork bottoms had to be stripped and repainted (seems to be a running theme with this build) and the wheels are temporarily fitted so I can move it around. Lovely set of Renthal clip-on's and Titax levers fitted and the swing arm should turn up any day now...Alan?...

1/12/10 Despite the calor gas heater going full chat, the garage is still not a pleasant place to be at the moment. Before the arctic conditions set in a disproportionate amount of time was spent making little alloy brackets for the reservoirs and the new race style switches for horn (daytime MOT requirement) and fuel reserve. It's the little attention to detail things that make a bike for me.

15/12/10 Sadly my cunning plan to use a rear calliper and hanger from an Aprilia and a smaller R6 sized disc have failed. I though I'd covered all the measurements but it wasn't until I mocked it up that I found the calliper fouls the wheel hub by about 5mm. Much head scratching ensued...

21/12/10 Have now decided to make my own hanger (eventually) so I may also try and find an even smaller calliper if I'm going to the effort...

30/12/10 We shall call this swingarm Mk1. It's not finished yet but we decided it wouldn't be possible to do a YEC replica so we've gone for filling all the holes, plating the sides and filling in the brace. Still need to clean up a few welds when my finger tips have grown back. The only thing that seems to work is P80 emery paper, if anyone knows of a power tool solution please let me know!
In the background you can see another eBay bargain, Ducati 916 Brembo discs.

24/02/11 I've not been entirely idle for the past 2 months just mostly...
Here are the fruits of my labour; Swingarm now fitted and all bearings and linkages lubed and cleaned. Modified 'bussa rearsets now operate a speed triple master cylinder which operates an Aprilia rear calliper which squeezes an R6 disc!
The problem of mounting said calliper was resolved by merging part of the Aprilia mount with part of the original Yamaha one, expertly welded by Alan at GTS.

02/03/11 Wiring and brake lines all hooked up now, body work just plonked on to give me a sense of achievement. We're on the home stretch now! Who knows it may even see daylight this month (but more likely next (the end of next month)). The link pipe and fairing stay are the only 2 things left to find/make I think. Oh, and re-cover the seat. Aaaaand balance the carbs...

27/03/11 Fairing stays mk2 finished in solid bar as hollow mk1 version didn't look so good.

28/03/11 Just the rear master cylinder to sort out as I'm hoping that is the issue with my hybrid rear braking system. Then the belly pan can go on and that's pretty much it... Ignoring the carb balancing until I've put a few miles on it as it may just need a clear out. Could be looking at tax and MOT end of this week!!

30/03/11 Embarrassingly I've just noticed I started this project on the 15/03/10, so it's taken me over a year to do what is essentially a re-spray and tart up. In my defence I did loose interest almost immediately after starting work and the only reason its gathered pace now is because I have another project that I (currently) have more enthusiasm for waiting in the wings...

31/03/11 This really is the home stretch! Have some lock wiring to do, a quick spanner check and its ready for a road test. Inevitably there will be teething problems but it could be taxed and mot'd by the end of next week. Gulp.

5/4/11 Bike in its new resting place outside the shop. As with any project bike it will continue to evolve, but for now its done. Taxed and Mot'd and one shakedown ride completed, which was fun but you do feel a bit vulnerable with no lights or mirrors. If I can find something suitable I may rig up a brake light to save some numpty in a tin box running into the back of me at the lights.
6/4/11 Did someone say teething problems? Its looking like one of the floats is stuck open and has filled the sump with fuel! I'm fighting the temptation to drain all its fluids and leave it parked at the shop but I'll give it one more go, oil change and carb strip tonight then...

Continue