What's that saying.. ''One mans junk is another mans treasure''... in this case its true. A friend of mine mentioned he had a friend (John) who had some stuff that may be of interest for the Honda build. The other day I drove down to visit John (who is an engineer at Bentley in Crewe), and after checking out his workshop and cool turbo Kawasaki's, drinking tea and chatting away for an hour, he gave me a box of various used Gpz 750 Turbo pistons for free.
Although some are beyond use, there are enough to make up a couple of decent pairs, which will take the Honda out to 370cc. Being Turbo pistons they should survive a little longer in the blown motor..
The Mercedes SLK supercharger new end case has been welded and machined, while the other end (the drive side) has a new billet case too. The rotors went back in with new bearings and spin nicely now. The next step is to make the inlet manifold which will connect the blower to the engine, which has been started..
Since we are working on a different Blast from the Past project this year, I'll keep it in this thread for now. So here's part 2 of the Spares Bike, a retro Z1100 based supercharged drag bike we are building from all our spare parts..
The engine in the Spares Bike isn't the one we'll use to race it, as its just for setting up. The race engine, another built from spares is now coming together. The head for which returned from Roger Upperton last week, who recut the valve seats, flowed it and no doubt did other stuff which I don't understand, but it does look very pretty...
We'll use another billet block, with 1327cc pistons, as that's what we've got. Almost all the machining for the engine is done now, next up is to make a fuel tank to sits behind the headstock. It'll be a sort of pyramid shape, with the top cut off. Made from folded and welded sheet aluminium, I'd prefer Geoff the Welder to make it, but Jeff wants to try and make it himself, so we'll see how it turns out.
That said no matter how much you do yourself, to get the bike completed its still going to cost money. So with progress at a snails pace, I've decided to throw some money at it, and hope to get it running before we're all pensioners..
Here's some pics.. In the second pic I'm pointing to a wedge like spacer, which was added to the manifold to tuck the SU carb in closer to the engine.
Made a start on the fuel tank for the Spares Bike, its going to fit below the top rails, behind the headstock. Its going to look like a pyramid, with the top chopped off, on its side... Well, that's the plan anyway.
A sheet of alloy was marked and cut out to make the top, bottom, front and back, the left and right sides will be welded on once the alloy plate has been folded and welded up.
As I sort of expected trying to fold the plate, using a vice, some steel blocks and some effort, didn't go according to plan. The plate wasn't following instructions and refused to fold neatly.
So we stopped, and will take it to a nice man who owns a suitable folder & press to get it shaped probably.
Got the main part of the fuel tank folded and cut. After checking the fit, the next step will be to drill the base to house the rubber mounts and outlet, then make the side pieces and finally weld it all together..
With the frame and main parts of the bike pretty much done, it'll soon be time to finally lift the bike from its frame jig. But first something would have to be done about that awful old seat unit. We did consider making one in alloy, which we may still do in the future, but for now we went for a cheaper option.
The old seat unit had sagged, twisted and cracked over the decades since it was made, and didn't even fit on the new frame in any case.
We sliced it up, narrowed it at the back, lengthened it at the front and build up the top and sides. That's what's going on in the photo below. All this work is just the start. The cut up old seat unit will be used as a template, which will be used to made a mould, which in turn will be used to make the new seat unit. That's a lot of hours of effort, but it'll give us what we need, with the only cost being fibreglass, resin and filler.
Here's a short video of all this, and you get to see the new frame jig too...
Been awhile since an update, both these bikes.. the Honda and Kawasaki are still being worked on, if slower than we'd like. Work on the rolling chassis of both is pretty much done, so attention has been moved to the engines.
For the Z1100 based motor, the standard conrods would be too weak for the power we want to get out of it, so we're making our own set from billet alloy. The small ends will be phosphor bronze, while the big end bearing will be machined out of an original set of Kawasaki conrods and pressed into the new alloy conrods. Easier to write than to do.. clearances will be critical for this mod to work..