Oil cooler air duct

The oil temperature on my Hayabusa is a bit high on prolonged sessions on track days especially at Knockhill. I was either going to shift the oil cooler from behind the radiator to the front or duct some cooler air directly to the oil cooler. I decided to do the latter. It will still get some air from the front via the electric fan and water radiator.


New air duct

New air duct in place

From above

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Concentric clutch slave cylinder

When I described my lack of clutch control precision with Andy from AB Racing he directed me immediately to a SBD part CLT-HCA-BUSA-01K. It is a custom billeted concentric slave cylinder for the Megabusa engine. The fitting of the part is fairly straight forward only having only to change the bleed pipe outlet from the water pump (as the rubber pipe was in the way). The pump housing bleed uniion was easily modified by cutting it off and tapping out the remaining steel tube stub to  a 7mm metric thread and making a brass union and installing a remote external 8mm brass elbow. The standard SBD fitting kit for the cylinder was perfect despite warnings from them that this part was designed to mount on top of their billeted oil pump.

Water pump modification



SBD part from top




Hewland part in same location

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Fuel overflow management

I have been hauled up on several occasions about fuel discharge during track days and sprint/hill climb events. This only happens when the tank is above half full. I fitted a Mocal valve which I thought would cure the problem as it has a dual function a) When the vacuum in the tank exceeds 0.5bar it will ingest air from outside. b) If however the tank pressure increases due to temperature effects (or sloshing) then the valve release in the other direction if that pressure exceeds 0.75bar. By this method the valve can act as a roll over valve and hopefully keep the fuel in the tank.

The problem occurs on track days when the fuel is warming up (so positive pressure) and the corners pull some g, if now the pressure release happens on a right hander then fuel is emitted momentarily till threshold of the valve closing is reached.

I have tried fitting a catch tank (jam jar) but this only delays the problem till the catch tank is overflowed. This results in dumping fuel from the catch tank between sessions.

The answer may be quite simple, let the main tank overflow when positive pressure exists, collect the fuel and suck it back in when the fuel is used up and the pressure becomes negative.

principle

catch tank mounted under chassis

I will let you know if it works.

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New brakes and oil pres warning lamp

  The brakes have been a problem from day one in that they were causing lost time at the hairpin and fading two up. They looked the part being single x drilled discs and early billeted 4 pot Dynalite's  from Wilwood.

I changed the discs to vented x drilled and grooved parts and as a consequence had to upgrade the callipers as well to the latest Dynalite forged part from Wilwood supplied by RD.

Dynalites with vented discs

The results were a dramatic improvement in both hill climbs and circuits.

Oil pressure warning

I have been advised by several hill climb veterans that a very bright visible oil pressure lost lamp is essential equipment for racing. This lamp BL0102-14-34 is the bees knees. Thanks to Matt as he had a spare in his garage.

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Seats crotch and Hans

I have been considering a safety upgrade to the Megabusa. I decided to invest in a set of seats that were more substantial than the GRP shells fitted and fit an additional crotch strap to the seat belts and Hans device for my neck.

If you want to know what a Hans device is then there is a very good explanation on Wiki (*).

The crotch strap is a simple addition to the existing Willans seat belts. It stops you sliding under the harness in extreme conditions.

The seats were ordered while at Stonleigh and are made by a company called Intatrim (*) and the product is called Endeavour. Although still a GRP seat it is a much more substantial product than the basic shell seats and they have thought about the crotch strap void in the design.

Hans adapter

A Hans device was purchased from JJC earlier in the year at significant cost. However I was never able to use it in the Westfield as the seat belt straps need to be precisely aligned with the seat apertures and the Hans device. This requires the attachment points in the Westfield to be radically altered. After some discussions with various scrutinisers at the track and after even more thought I designed and fabricated  a Hans adapter using the existing Westfield seat belt attachment points. You can see not only have the attachments been aligned horizontally with the Hans device but a 50mm elevation to the attachment has been applied because of the Hans thickness resting on your shoulders.

The adapter was fabricated out of 4mm sheet steel and bright steel studs taped and welded in place on both sides of the plate.

I propose to submit this for scrutinising soon at Kames.




Hans adapter

Hans device

Drivers seat with new belt attachments

Comparing drivers and passenger seat belts

Passenger seat belt points

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References (*)
Hans explanation: http://en.wikipedia.org/wiki/HANS_device

Seat manufacturer: http://www.intatrimtelford.co.uk/index.php

Engine prop shaft adapter

The Hayabusa engine normally has a toothed gear to transmit the power from the gearbox to the rear wheel of a motorbike. Wesfield in their cars mount a special adapter on the gearbox output shaft that adapts it to a split Sierra drive shaft. The adapter is normally made of mild steel and is rigidly attached to the gearbox shaft via a large M20 lock nut and a large washer. If you trawl the forums this nut comes undone with amazing regularity. Mine unwound at Croft on 7th June 2014. It was trailered back home as I had no chance of repairing it at the trackside. The mild steel adapter was badly damaged and I did not want the gearbox shaft to go the same way.

I took the advice of Andy at AB Racing. He has a special adapter made to his exacting requirements which is reported to solve the problem. It is designed to be loose fit on the gearbox shaft unlike the Westfield part and is made of hardened steel.

It is unfortunately about 10mm shorter than the original Westfield part so I had to make an alloy spacer in the lathe to make it all fit back together.

The M20 nut was also modified to make the adapter a loose fit on the shaft and I tightened it up such that it will not come off again. I used the permanent nut thread fluid to bond it up tight.

I have no idea if this will permanently solve the problem but is seams like a good approach. Time will tell.




Westfield adapter after failure

Gearbox splines

10mm custom spacer



Nut modified on right to remove some of the step



Reassembled

Update 11th Sept 2014

Kept a regular eye on this part of the car and it regularly gives an 1/8-1/2 turn between race events on the cap head screws no evidence of the 32mm nut loosening again. I decided to wire the bolts to ensure they don't come loose again. I drilled the cap heads in place using some carbide burrs (long job).

Wide carbon wings

I was having difficulty changing the tyres at the trackside with the standard Westfield wings. I was also having difficulty sourcing wider wings. Carbon Copies (Warren Sheridan) made me new ones in carbon. Unfortunately due to ill health he has had to give up his business. It took a long time to get these parts but he came good in the end with the help of his son. Top marks for commitment right to the end. The wings now match the headlights, see bottom image.



From front

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