9th May 2008

Right, I'm going to get my excuse in early. Progress in early May has been slower than expected because I've spent quite a while turning Steve's independent rear suspension Fury chassis into a live axle Fury chassis after he decided to turn his already fairly battered Fury racer into a short wheelbase version. As ever, a job I said would take a day is taking rather longer than that. However, I have still managed to get some work done on the Furyracer...

Oil system - air oil separator

Oil surge is an enduring issue with bike engines in cars. Some seem fine with no mods at all (ZX9R). Some are OK as long as they have baffles (Fireblade, <2003 R1s). Some have a distinct tendency to blow up if they're not dry-sumped (Blackbird, Busa). The evidence from the hillclimb and sprint guys is that the 2004-2007 R1 engine is OK if it's baffled and overfilled, hence the fact that I'd already fitted a baffle. Chatting to some other people in the RGB world, however, suggested that under racing conditions the 2004+ R1 has a tendency to throw its oil out of the crankcase breather to the point where it starts to suffer from surge. One suggested solution to this (other than coming in every 2 laps for a top up of oil) was to fit an air/oil separator in the crankcase breather line. This is the start of my homebrew crankcase air/oil separator. The idea is that the air with the oil in it comes in at the top of the box, is forced to go down and through the small holes, which causes the oil to drop out of the air, and the air then goes out of the box while the oil drains through a pipe in the bottom of the box.

This is the separator all welded up and roughly where it's going to go. The input will be a straight pipe from the crankcase breather. The return line to the sump is the external sight glass I've already made, and the output from the separator goes into the catch tank. The catch tank, rather than breathing through the 4 small holes drilled in the top, is going to have a K&N crankcase breather added to give a bit more back pressure to help the air/oil separator work. Hopefully the separator will work sufficiently well to ensure that the oil stays in the engine rather than being dumped in the catch tank. There are various reasons why it might not - the air/oil separator is total guesswork, the return line from the external sight glass is a rather small diameter since it wasn't designed for this, and other paddock sources of info have suggested that it's also necessary to add another breather from the cam cover (which I really can't be arsed with). Anyway, here's hoping...

More oil stuff - possible sump mods

One other possible issue on the oil side is the angle I've installed the engine at. As you can see, I've installed it so the baffle (which is level with the joint between the sump and the crankcase) is level, and the bottom of the sump is at an angle. This was on the advice of Martin Bell, formerly of the Kit Car Workshop. However, on the bike the bottom of the sump is flat, and since the pick-up is about halfway across the sump (as you can see here) it isn't even at the lowest point of the sump. Given that increasing oil capacity in the sump is rarely a bad thing, I've decided what I'll do is modify the sump by welding in an extra section so the bottom of the sump is level with the ground. Then there's just the problem of modifying the oil pick up so it fits, which is tricky as I think it's plastic and therefore not weldable with the gear I've got. Still, I've won a spare 2005 R1 sump on eBay, so if it all goes horribly wrong I can just revert to this set-up. </and then the cat died>

Airbox mods

The standard R1 airbox couldn't be used on the car as it was. From the TBs it goes up and left (looking at the engine from the rear of the car), ending up about 18 inches above the bonnet line. While I appreciate a decently sized bonnet appendage as next as the next man, a monstrosity of that size screwing up the already far from perfect aero seemed worth avoiding. And you can't simply turn it round 180 degrees - the bit that goes above the TBs has recesses in it for the stepper motor that deals with the secondary throttle plates and other similar gubbings. So what I've done is cut'n'shut the airbox - I've cut the bit directly above the TBs with the recesses in it away from the rest, and spun the rest of the airbox round 180 degrees with an ali adaptor plate to fill in the gaps and compensate for the bolt holes no longer being in the right places. And here it is. I'll leave it to your imaginations what it looked like without the modifications...

We're not quite home and dry on the airbox front though. The air filter (mine came with a K&N panel filter, natch) fits just above the layer of foam you can see on the bottom of the airbox. Just above a space fairly comprehensively filled with thermostat housings, fuel lines and crankcase breather hoses. The prospect of getting a decent cold-air feed into the filter in this position seems somewhat remote.

What I'm planning to do instead is to use a cone filter on the end of some flexible hose, with the cone filter sitting in a sealed enclosure underneath a bulge on the bonnet from which I can take nice cold air. The other end of the hose will then go into a fitting which I'll add onto the vaguely flattish vertical face on the outside of the airbox. Then I'll just need to plate over the hole where the panel filter's supposed to go. And the big advantage of having the modified airbox in place is that I can now cut a suitably large hole in the bonnet for the airbox, which means that once I finish cutting the radiator and headlamp holes in the bonnet, I can fit the bonnet and the bonnet pins and catches, which means that I can remove the scuttle and sidepods (with bonnet pins fitted) and spray them which means I can start bolting stuff to the scuttle, like the electrics... Mind you, I've also got to recommission the spray booth.