Saturday, 5 October 2013


Westfield Megabusa upgrade

2009 Megabusa Oct 2013

Megabusa 2015

See also:

Date              Title / web link
Key words
5th Oct 13   
History, faults etc  
9th Oct 13
Mud flaps, Protec Shocks, Aero screen
11th Oct 13
Investigation, reverse box, gear change etc
14th Oct 13
LED Europa spares
18th Oct 13
Move battery, Rear stone chip protection, rear closing panels
2nd Nov 13
AB Racing paddle shift install
12th Nov 13
Making the exhaust comply, noise, CAT
17th Nov 13
Automatic reverse lamp
26th Nov 13
More MSA requirements
5th Dec 13
Rear storage
10th Jan 14
Oil catch tank mods
22 Jan 14
Roll cage and side doors
27th Jan 14
Attaching the GRP half doors

04th Feb 14
Finishing touches, boot box lid
12th Feb 14
Gear selected indicator
20th Feb 14
Adding places to put competition numbers etc
18th Mar 14
ARB install
20th Mar 14
Cooling fan upgrade
27th Mar 14
Summary and comments so far
11th Apr 14
Tonneau and rear view mirror
1st May 14
DRE shift lights
7th May 14
Return from Stoneleigh with new headlights
3rd Jun 14
Remap the Power Commander
10th Jun 14
Carbon Copies made custom wings
19th July 14
New seats, crotch strap and HANS device
4th Sept 14
New Dynalites + vented discs and Oil warning
11th Sept 14
Resolving problems with fuel overflow
15th Oct 14
Better clutch control at the start line
31st Oct 14
Improved air flow to oil cooler
12th Dec 14
Improved heat protection exhaust exit
22nd Dec 14
Reducing weight of battery (8Kg)
13th Feb 15
Reducing weight of hubs and carriers (8Kg)
20th Feb 15
Carbon bonnet (3Kg)
22nd Feb 15
Progress report 2015

I wanted a car more tuned for track day events and hill climbs. I settled on a Westfield Megabusa as the car of choice as they do hold the money on the second hand market and go like hell. I have just built a Sylva J15 and I expect the depreciation on that to be extensive and I did not wish two cars in the stable to be dipping away at my daughters inheritance.

I fixed on the specific car, shown above, it has one or two restoration/repair opportunities and it was being sold below it's potential market value because of the reported problems. I also needed a project for the winter of 2013/14.

It is a YR2009 car registered on a Q plate. The chassis is an original Westfied Megabusa  manufactured in YR2004. It is a wide body with fixed wheel arches and fully rose jointed.  The engine was manufactured in ~YR2000. The car has been painted in two pack red. It is a nice car and looks very presentable.

I have had the car for a month now and here are the list of problems most of which were reported by the previous owner and of a trivial nature.

* Differential making a noise under deceleration: Loose bolts
* Differential breather not attached, spraying oil on casing: Added pipe.
* Light switch intermittent: Corroded switch replaced with second hand part
* Bezel around instruments falling off: Tiger Seal used to reattach
* Offside rear light lens broken and some bodywork damage in the same area: See bodywork repairs
* Fuel gauge not reading accurately: Sensor had never been adjusted to tank when installed.
* Stone chips both sides of rear mudguards: See bodywork repairs chips no longer present.
* Clutch slave cylinder leaking: Replaced seal and honed cylinder. See picture.
* Intermittent instrument lights and sticking temperature gauge: Not done yet low priority
* Seat backs  separating from main body of seat. Also can't reach the pedals due to fixed location: Repaired seats and installed adjustable runners see picture.
* Exhaust too loud (>99dB), can end cap cracked around input pipe, no rubber mount at tail fixing, also future MSA scrutinising issue: Welded cracks and replaced wadding. New CAT needed to comply with MSA rules.
*Nearside rear shock absorber leaking: Replaced see picture.
* Steering wheel too close now that seat is in the correct driving position: Made up new spacer and removed quick release for now. May have to revisit this issue once full roll cage is installed.
* Fuel swirl pot bracket broken, pot moving about with engine vibration: New bracket made and glued on (as welding it was too complicated for now).

First repairs

The car runs exceedingly well and has blistering performance (not of this world) even before most of the above repairs were put in place. The majority of the repairs took less than a day or two however the bodywork restoration took a few more.

The bodywork was relatively easy to repair the car having a two pack finish and made of GRP.

Hewland slave cylinder

AVO shocks

offside rear body damage

Stone chips removed

Seat repair

New runners welded up

Future plans

My intention is to hill climb the car on some of the Scottish tracks to MSA rules. I also want to enhance some of the features.

* Full roll cage
* Tow points, trip vane and signage
* CAT (more discussion on this).
* Upgraded aero screen
* Extra cycle wing stays to support front mud flaps
* Carbon effect stone chip guards for rear mud guards


This is a difficult area for a bike engine car. Production cars had ECU's and CAT's since the late 90's with engines and ECU's designed to meet the test. Bike engines were not fully compliant with this technology till about 2008. These developments were brought about because the emission standards were lowered. This is expressed by the Lambda ratio of un-burnt fuel to oxygen being in the range of 0.97 - 1.03. This car was  no exception and passed this lower limit in 2009 at the IVA test (it says so on the log book). I am not sure how it did pass as it would not pass that test today as there is no CAT present. If a CAT were present the Hayabusa ECU of that age (YR2000) cannot support such a device.

The MoT is not a problem as Q plated cars with a bike engine are subjected to a wider limit because of the above issues with bike engines emissions.

The MSA rules state that a CAT must be present on a 2009 car (I think this is called catch 22 is it not?).

Some have said just add a CAT and forget about the ECU. Fitting a CAT with no ECU to control will not maintain the correct temperature. An over fuelled BEC can melt a CAT I am told! I am going to fit a CAT and see where it leads.


Angus:Who applied the top coat of paint, thanks for the time.
Matt: Who supplied some of the s/h bits.
Gerald: Who helped me pick up the car on a trailer.
Aliblast (Alastair McGill) who fixed the slave cylinder.

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