GPZ900R sidecar project 2010 (updated 29 march 2010)

These are the pictures so far. The plan is to build a super-strong continent-eating sidecar from a donated 1991 Kawasaki GPZ900 and bits of metal. The sidecar is to be adaptable to various loads, mainly a big box for a summer trip to Finland that can hold luggage and 2 medium sized dogs.

It was inspired by this:

As it's been built and the parts assembled the design has changed to suit materials and circumstances! It's coming along well, but isn't quite what I had in my head to start with!

There are a few innovations that may be judged wondrous or bodgery :o)

clamps make much use of exhaust clamps for simplicity, availability and cost. This is part of the assembly that i'm using instead of a bolt with an eye in it that most sidecars use. The reason being that I've seen too many of these snap and they're expensive and hard to get hold of.

clamps and arms in progress (bedroom workshop)

arms are 20mm threaded rod and 25mm (3mm thick) box section.

subframe in progress, also 25mm (3mm thick). The bottom rails are the same height as the sump plug.

Rear sidecar mount in progress, clamped with 3 arms and taking up the battery space.

Frame found on ebay for £60 :o) saving loads of hassle. Possibly from a 60's watsonian it's built from 1.5" tube of about 4mm thichkness and covered in cast iron lugs. Ludicrously heavy, about 50kgs! No need for ballast then. (update: ballast still needed!)

with a tube frame and clamps, the arms can be just about anywhere. I decided to move the arms right out to make the whole things stronger.

lower clamp arrangement allows for sidecar-lead, toe-in, bike-lean-out and height adjustment! Top struts then lock the sidecar in position.

clamps shouldn't fail catastrophically as there are 4 and I can carry spares which are easy to source. I have seen several of the normal sidecar bolts with an eye in the top fail, hopefully this design is stronger and easier to fix in the field, but it does take up a lot of room.

Rear mount had to be further back from the frame to make space for my leg! Clamped in position, I think it will hold, but I can always weld it if I have to.

Professional workshop facilities!

Fucking landlord's rose bushes kept snagging my jumper, nearly took the grinder to them!

Left half of the sub frame removed for final welding and lacquering.

After final welding all the mounting holes moved :o(    Grr......

Sub frame fixed and mounted. Held on by 2 x m8 bolts near headstock, 1 x m10 to engine and 1 x m8 near foot peg (and same again on the other side too) The 1 x m8 by foot peg is worrying me a little. Reaching the centre stand mounts wasn't simple and i wanted to retain the stand for wheel changing.

Whadda you know, the sidecar is exactly the same size as a euro pallet! The cut outs are for the mounting points and the wood has been varnished. (update: this material will do for now, but it is much weaker than normal ply, the middle layers are just bits, and will need to be replaced.)

Propped up next to the bike to measure where to cut the upper struts. Workshop has moved to the street! Also Menina is the first passenger :o)

The box section was just a little too tight for the threaded rod, so I opened it out (with some difficulty) using a 20mm drill as deep as I could and then used extra nuts to build up the tube to allow as much adjustment as possible, about 20 cm.

Only 5mm wider than my CB400 and Velorex, but a huge amount more usable space already!

Wheel is from an Austin Mini and hub contains a drum break, which I can hopefully hook up some day.

Smug rider and dimensions so far are below....

(updated 29 march 2010)

Here it is compared to my Honda CB400 Super Four and Velorex. It's about 30cm wider and 15cm longer (and 57 bhp more...!)

Filling the radiator proved to be a big hassle with the massive pipes which are needed because of the silly angles of the outlets on the radiator. I will have to get some copper heating pipe corner pieces 22mm internal diameter ones should do as the copper is a bit over 1mm thick and the heating pipe is 25mm on the GPZ.

Just lashed together by eye for a quick test ride. Goes ok! May need a steering damper and full throttle 1st gear made the front go a bit light with ensuing scariness! Ammo tin is for a 12v Diesel van battery for extra juice storage and ballast.

After going around the block for 15mins the left side of the radiator was too hot to hold for long and the right side merely lukewarm. Great news as the GPZs easily overheat. If it runs too cold I may have to cover up part of the radiator. The little frame at the front will also hold the obligatory spotlights, and prevents the radiator wasting any more space on the platform.

I plan to extend the base by about 12"/30cm at the rear and move the rear diagonal strut to where the wood ends now to make the space more usable. Hopefully the electrics will all be hooked up by this weekend ready for an easter trip :)