Completely Stock standard - never been opened except for NSU fix, timing chain gasket and Valve clearances. 

Currently 50,000kms as at February 2016.


In order to gain more low down torque and smoother, crispier power delivery, I chose to go down the FCR route. Sourced of e-bay in the States, I purchased this FCR MX39 (39mm) which is from a Yamaha YFZ450 Quad bike. The carby features an air cut valve which reduces popping on deceleration.

I had an aluminium adapter 54.5mm ID x 58.5mm OD x 26mm long made up at a local engineering shop which I then JB welded to the intake to match and reach the stock airboot from the airbox.

Minor modification was required to the throttle cam housing to accept the stock throttle cables.

The Throttle position sensor and wiring was removed, the shaft shortend and the housing plugged, in order to make clearance from the fuel tank.

I added and R&D fuel screw to make easy adjustments to the fuel/air mix

Starting with MXRobs recommended settings, through some research, trial and error I settled on the following settings to better suit my (Northern Australia) climate and fuels.

  • 155 Main Jet
  • 40 Pilot Jet
  • 85 Pilot Air jet (standard)
  • 100 Main Air Jet (standard - fixed)
  • 85 Starter Jet
  • 35 Leak Jet
  • NCVT (Honda) needle on 2.5
  • Fuel Screw 2.25 turns out.
  • Aftermarket Vaccum Release plate
Bottom end snap is sensational and the bike pulls clean and strong right through the rev range. There is no longer any surging at any speed and my fuel economy has improved to average 21.50km/litre.

pinging and detonation detected on fast hard throttle and under load. May have been poor fuel but richened up both pilot and main jets.
Current settings now :
  • 160 Main Jet
  • 45 Pilot Jet
Economy dropped to 19 km/litre but power much better and no pinging on hard throttle

dropped main to 155
dropped pilot to 42
dropped starter to 72
deleted R&D fuel screw due to perishing and fitted standard screw to be changed for a RHK extended.

Below -    Airboot adapter                                                      - The fitted Carby

Below -  Vaccum release plate                                    R&D fuel screw remounted to engine case


 I get my jets etc for this carby from:

(Click below to go there)


In order to satisfy the air requirements of the non stock FCR Mx Carby, drastic modification of the airbox was required. 

I followed MXRobs recommendation as per his photo to the right. (thanks MXRob)

I am also running a Twin Air Filter with this setup.

Another restriction in the form of the backfire screen in the intake boot has also been removed.


On the lookout for one, I came across a very nice GSXR muffler for sale in Melbourne on ebay for a really good price and it also came with some GSXR indicators. I won the bid and the pipe arrived a few days later. It was in very good shape and had just a small dimple in it that was hidden by the sidecover any way. It was the X40FI pipe which is the one I wanted due to it's size and also it's weight being mostly Titanium. Now I just had to come up with some fixtures to get it mounted up. Once I had eyed off where I wanted the muffler to be I cut a triangular shape hanger bracket that would mount to the original muffler mounting tab on the frame, the front right hand grab rail mount (inside of the frame) and the pipe itself. The pipe would mount to this bracket via an exhaust rubber grommet to allow some flex and for expansion as the pipe heats up. I now had to come up with a midpipe and planned on using the stock header (ground down weld). I searched a few engineering shops and found one that had some offcuts of mandrel bent stainless steel pipe that was the exact dimension I was after. I grabbed a few that had 90 degree bends in them. With the Muffler mounted where I anticipated it would remain, I set about playing with my lengths of bent tube to work out some angles. The front part off the midpipe would be cut from the stock muffler and incorporate the mid mount and mid rubber mount in the frame (again for flex and expansion). Once I had cut my bits and marked where each one would meet, I took them to the engineering shop to have stainless steel welded together. I had an ADV aquaintance make up a stainless flange for me which would be welded to the midpipe once everthing was fitted in place on the bike. It all came up pretty well and I have been happy with this setup. It's heaps lighter than stock, looks good, looks factory, is free flowing and is not too noisy but has a great note to bring out the real thumper in the bike.