Front brake system up and working

Hello - finally managed to find some time to make some progress with the project. I've now got the new master cylinder connected to the gsxr brake system. I had to find a bit of goodridge hose with one banjo for a 7/16 x 24 harley style master cylinder and the other end to fit the 10mm Suzuki brake system.

The new master cylinder set up is great and comes with two micro-switches built in. The clutch version is the same, but is set up for a cable clutch.

Under the seat....

Ok, so now getting somewhere with fitting in the electronics. This photo shows the area under the seat, with a battery holder, a fusebox and the CDI unit. Still got to find somewhere to fit the regulator/rectifier and the starter relay.

Drilling stainless steel

I've been working on the stuff under the seat to hold the battery, fuse box, starter relay, CDI unit etc and making some plates from alloy plate. Which was fine and no problem. However life got a bit more difficult when it came to drilling some holes in the stainless steel plate - my HSS drills seemed to have little impact, so after some internet research I've getting hold of some cobolt drills. I also found out that heat, through drilling, can make SS harder so you have to take it slow and easy....hmmmm...

A short movie

There is a soundtrack with this movie, so turn up your volume (or not, if you are at work or something with no headphones!).

I've put a higher resolution version up on youtube, if you want to view that instead, as it's a bit better!

This weekend I also got the ZRX1100 back together and running, after putting in some new clutch parts to cure the dragging in gear and a bit of a rattle. The clutch is working much better now and I seem to have cured those problems, which is great. Here's a couple of photo's of that little job. Cornwall Kawasaki supplied most of the little spare parts

A sunny sunday

As the weather was good, I cleared up the garage and got the front and back end onto the bike, now that the frame is back in. Next steps are to work on the battery box and spaces for the fuse box and other electrical parts. The handlebars by the way are 31" wide custom made from 316 stainless steel 1" bars, with a set of rear slanting risers fitted to the GSXR750 top yoke. The bars are good and wide and came from 'Piggin Pipes' in Ilfracombe (who were very helpful in making a pair with the right spacing on the knurling to fit my risers).

Progressing now!

So now I have the engine mounts, I can get the engine in the frame! Hooray. And it all fits nicely.

Thanks to Ralph!

A package arrived this morning all the way from Ontario, Canada containing a whole load of engine mount parts that have proved really hard to get hold of. Thanks to Ralph in Ontario for searching these out for me - especially for the two spacers on the rear upper mount that are like gold dust!

Squeezing the rear end in...

Fitting the GSXR swingarm and rear shock into the GPz frame also required some engineering ingenuity! So here's how it was done ( by Pete at Lite Welding Ltd near Stroud).

Top Shock Mount - this was relatively simple as the GPz upper shock mount was the right size for the top mount of the GSXR1100 shock. All that needed to be done was to lathe down the bearing bush.

Bottom shock mount - much more effort required here. Pete cut off the old GPz mount and created an all new mount, engineered to make the frame sit level with the new front and rear end (clever stuff).

Swingarm - ok, so the GPz swingarm spindle is thinner than the GSXR one, but it fits the frame so it's easier to use that than try and drill out the holes in the GPz frame. Pete made up a pair of 'top hat' spacers to take up the space within the swingarm bearings and also between the frame rails.

Other issues

Got to find some bolts to securely attach the top and bottom shock mounts. Also, need to trim down the plastic chain guard as this currently catches on the frame rails.

Of course, in the future, the rear sprocket and front sprockets need to be lined up!

In the first photo below you can see the swingarm in place with the top hat spacer/bearing bush on one side. Below this you can see the new bottom shock mount fitted.

Attaching the front end

Ok, so here's what Pete (the magic welder at Chops n Bobbers) did to make the GSXR yokes fit the GPz headstock:

• Cut off the GPz turn lock tab
• Welded on a new turnlock tab that works with the GSXR bottom yoke

• Broke a chisel getting the old bottom bearing race off the GSXR bottom yoke!
• Lengthened the GSXR steering stem by cutting it in half and then welding in an insert
• (note that we couldn't press the GPz stem out of the original yoke as it's welded in, and also the GSXR yoke is alloy which would have been hard to weld a steel stem into)

• The top bearing & race was the same size on both yokes, and I sourced a custom sized bottom bearing & race with an ID to fit the GSXR stem and an OD to fit the GPz headstock
• The threads on the steering stem were a bit poor so those were recut

A useful discovery

I sometimes wonder how much harder this project would be if it wasn't for the Internet. It's such a great source of information, and parts. Perhaps the bike should be called the 'ebay special' or something. eBay is an amazing source of parts. I remember many years ago having to go to a bike shop (actually was Bikewise in Abingdon) and searching through several inches of computer print out to find the right parts and then the shop would order it, else having to spend many hours on the phone ringing breakers to ask if they had the bits (and hanging on the phone while they went off an looked somewhere). Also getting hold of original parts wasn't easy either, as bike shops were the only people with the microfiches.

Anyway, I was thinking about brake light switches (as you do...) and the problems of attaching them to the frame (in the case of rear brake light) or how you fit one to a custom front brake lever. So I started a google search in microswitches but it wasn't long before I found out about banjo bolts with built in switches - how great are they? Totally solves the problem in a very neat way. Now just got to work out what size I need...

Mark

The big jigsaw....

Ok, so I've got a frame, a front end and a rear end. Problem is none of this stuff fits together properly. However, I wedged it all together to see how it looks. The short GSXR forks work really well and the whole bike is quite low and long - looking good. Especially that fat back tyre.

Next step is to take the bike down to Pete at Chops n Bobbers near Stroud to get it all welded up and fitting properly. As well as sorting the rear end, the front end needs major adjustments as well - for a start the GSXR headstock is too short for the GPz head tube, and the turn stop tabs don't match up at all.

GSXR Rear End

So here's another fine ebay purchase - a complete rear end from a 1991 GSXR1100M. The swingarm is narrow enough to fit into the GPz frame, which is great although the spindle diameter is wider than the GPz so that's going to need some thought. As will the shock mounts as they don't match up at all.

To do list

Lists are always useful and these are my thoughts on stuff I've got to work out how to do!

Rear light - need to think about shape and positioning along with numberplate holder.

Foot controls - got some tidy ZZR ones, which mean that the frame lugs need changing, plus a new tab for the rear brake reservior - also need new goodridge hoses. A new gear linkage rod also needs making. Need a brake light switch (probably on rear brake pedal).

Chain guard - not got one at the moment

Sprocket alignment - rear sprocket carrier needs machining to move the sprocket inline with the front one.

Seat - think about recovering and how it attaches to the frame

Handcontrols & switches - What switches and where - need to fit 1" bars and look cool! Throttle and linkage to the carbs. Clutch cable. Need switches for ignition, starter, horn, main lights and dip/main beam (no indicators).

Instruments - need to think about speedo as a minimum, plus some idiot lights such as oil, neutral and high beam. Also how and where to mount it. Do I need a tacho?

Battery box & electrical components - need to mount the battery safely under the seat, plus find a place for the Rectifier, CDI unit, fuse box etc. Hopefully the coils will still mount under the tank.

Wiring - a big job. I have a standard GPz loom but I think this bike requires something more bespoke, especially as the handcontrols and lights are not standard

Side stand - probably needs shortening as the bike doesn't seem to lean over enough to feel safe with the standard length GPz kickstand.

Fuel tank - needs an aircraft style filler fitting and need to look at the fuel tap. Then it's going to be grit blasted and powder coated. Also the fittings on the frame need to be sorted.

Frame & wheels - also need to be grit blasted and powdercoated (black and orange I think)

Front Mudguard - needs painting to match wheels & tank

Side panels - need making from mesh with edging and new tabs to sit them within the frame rails and not on top.

Engine - need to fit oil cooler, and crankcase breather pipe, plus fit carbs and get K&N air filters (check if carbs need rejetting). Also need last couple of spacers for the top rear engine mount.

Brakes - front & back need checking - shouldn't be a problem. Might need new goodridge hoses for right lengths. [Brake light switch]

Fasteners - preferably new stuff, stainless steel?

Headlamp & brackets

Frame - fitting new rear swingarm & wheel, fitting front end & yokes etc - turn stop tabs need moving

I think that's about it for now - have I forgotten anything?

Front End

So this is the front end I bought off eBay. It's from a 1989 GSXR 750 K and comes with a pair of yokes, 43mm forks, wheel, discs, brakes and speedo drive. All ready to go really. The top yoke has been converted to bar clamps with a pair of standard risers. I will have to change this as I want 1" bars rather than 7/8.

Why, oh, why the GPz?

Good question -why go for this engine and frame? The answer is that I'm not sure really. I've always liked the old Zeds, and had a fine Z750 many years ago. I've also got a ZRX1100 in the garage which always was my dream bike. For this project I wanted an aircooled Kawasaki engine and the GPz is a development of the old Zed four cylinder motor - plus the GPz engine also has the oil cooler fitted, which has got to be worth having. I might have been interested in a GS750 but those are getting harder and harder to find these days, and are also fetching a lot of cash. I guess there are becoming classics now.

My starting point!

So, this is the basic frame from which the whole build is starting. It's a modified early 1980's Kawasaki GPZ750 A1 frame, with monoshock suspension. I have a 1984 GPZ750 A2 engine to go in it. Obviously it first needs some wheels, which is my current task. They are going to come off a more modern bike, with better brakes.

I think the fuel tank came off a Z750 LTD model. I'm not sure why the frame is a fetching shade of yellow as I don't think any GPZ's were ever that colour? Not that it matters, as it's going to shot blasted and then powder coated in black at some point.

Bringing it home

White Horse

Ok, so at the moment I live in Wiltshire, but I grew up in the Vale of the White Horse and just knew that somehow the Uffington White Horse had to feature somewhere on my bike project. So, I designed the graphic on the left, which I hope to have laser cut into stainless steel or Alloy which will then go onto the Alternator cover etc on the engine cases.

All about a bike...

Hello & welcome to the bigfastbikes blog!

This blog is going to be entirely about motorbikes. In fact, mostly about one bike - the bike that I am building....very slowly building. Even with many years experience of spanners and the internals of bikes, deciding to build a one-off custom bike is still quite daunting. There isn't much specific advice out there on how to do things, so this blog will aim to document my trials, tribulations and hopfully successes, plus a lot of photos as we go along.

The basis of the project is a 1982 GPz 750 A2 engine. Actually, that's not the very start of the project. The whole thing started off with the eBay purchase of a Z750 rolling chassis for £85.

Then I bought the GPz engine at the Bristol Classis bike show in Shepton Mallett a couple of years ago and the course of the project started to change! In fact you can see two engines in the top photo - a very old Z750 and a nicer GPz750. I sold the old engine on ebay so someone who does some racing and wanted to move up a class with a bigger motor.

Happy reading,
Mark