XJ6 Upgrade

[XJ6-boy]

Ok I am new on here and 18 mths ago purchased an XJ6N and proudly took my time running her in, the bike stands now at just under 5500 miles. I have to say it handles well but I have never been exactly bold over with the engine performance and have always thought it lacked grunt.

After readying an MCN review on the bike which stated the throttle bodies have been reduced from 36mm to 32mm and being and old school mechanic it has been bugging me how to produce a cheap way to increase performance, when it use to be carburettors it was simple, put bigger carbs on but Fuel injection is not quite as simple, so I researched the subject (remember the xj6 is based upon the 05/06 r6 then redefined as the FZ6 Frazer which was rather mad-fast) when you actually look at the specs on a Yamaha service manual there are only three main difference between the FZ6 Frazer and the XJ6. 1 ignition timing by 1.5 deg, 2 the valves open longer on a Frazer than on the XJ6 and finally the throttle bodies internal dimensions are smaller on the XJ6 (32mm) the actual bodies them selves are more or less identical.

So guess what I purchased a throttle body from an FZ6 Frazer (cost me £50.00) did some miner changes and put them on my XJ6, what a difference. normal riding is about the same just a bit more responsive so is still nice in traffic (although the 3000 rpm to just under 4000 rpm dead zone is still there) but when you hit 4000 rpm and pull the throttle back all I can say is you need good gripe to hold on and how this bike should be.

Ok so just for you lot wanting to know how this works in general terms, you have increase the air flow by 4mm which is detected by the air flow meter, this tricks the ECU into supplying more fuel, more fuel equals more speed which is good and far cheaper than a £500 to £1000 exhaust job and has removed my boredom factor which again is also good.

If anyone wishes more details on how to do this modification please let me know, if you have patients time and some mechanical know how you can do this.