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[Rattlebattle]

Yep. One wonders if the Himalayan has one?? You'd think so, or does it just run badly at sea level...... Most modern EFI engines compensate for altitude; it's one advantage they have over carbs.

[ric]

I adjusted my pendulum barometer using the readout from my Triumph barometric sensor. Now it's as accurate as looking out the window

[Alan R]

Hi Guys------ REVBAND, all motorcycles have a altitude compensating device sat on the saddle.....As soon as the air becomes too thin the rider collapses into unconsciousness and the bike stops !!--LoL ....RATTLEBATTLE... there are many carbs that compensate for altitude ... have a look at this}---- http://www.theaerodrome.com/forum/showt ... hp?t=31874 ------ Conversely if you take an ICE down a deep mineshaft then the opposite happens because you now have a much bigger column of air above you which is denser and thus has more air than fuel in your mixture and thus runs weak !!

[AndyMc]

Thanks guys, I'm not looking for more performance. If I wanted to go faster I would buy a different bike. I'm looking for a better sound son have purchased a turn out pipe. Not very expensive so if it doesn't work its no great loss.

[Paulk]

For Info - "That is why people remove O2 sensors and then remap to suit the exhaust/inlet configuration" I have done this to my Hinckley (along with nicer air filter). It was irritating jerky at low throttle now it has cured that as well as an extra 20 mile per tank full - not what I was expecting.

[Rattlebattle]

Me too. I fitted a carb to my C5 because I had a few issues with the EFI on it and the only ways to tune it for different exhausts and inlet systems are either a buy a Power Commander V and a suitable map (which you would have to change again if you fancied a change of exhaust etc), a Dobeck (?), cheaper but similar to Power Commander V but not as sophisticated, or a carb conversion. I chose the latter because it was less expensive than the PCV to buy and to make subsequent changes. It works well and IMHO looks better. No real need for the MIL, which I may replace with a nice ammeter. I'm far from being an anti-EFI Luddite though. On my last-of-the-line air colled Thruxton (bought because unlike the new l/c ones you can play with the tuning) I've remapped it to suit the airbox baffle removal (an easy and free fix that liberates 2bhp), the replacement air intake and air filter, the removal of the awful secondary air injection system and O2 sensors and the replacement of the anaemic standard silencers with Triumph Offroad ones. The result is a 16%increase in torque, the elimination of the dreaded off-idle stutter and perfect fuelling from tickover to WOT, with the rev limit increased by 500rpm. Waht a difference! How anyone can be satisified with the strangled performance of the standard bike is beyong me. Or with the brakes and suspension, which I've upgraded too. By comparison the options for the UCE are limited, though I might try rearding the inlet cam by two teeth, which apparently improves the mid-range no end. I'll wait until I fit a one tooth larger sprocket. Having recently changed the oil that can wait for a bit.

[Presto]

Fitting a ‘turned out’ short silencer on a C5 Efi isn’t recommended as it will not provide the backpressure needed for the lambda sensor and ECU to operate as they should. But it may work! Let us know if it does – or doesn’t.

[Rattlebattle]

How does back pressure affect the ability of the O2 sensor to do its job i.e. determine the amount of oxygen in exhaust gasses?

[Presto]

I quote: “The ratio of partial pressure of oxygen on one side of the cell to the partial pressure of oxygen on the other is identical to the ratio of ion concentration. It should be apparent that the partial pressure of any particular gas is directly proportional the total pressure (all other things being equal).


This means that a higher total pressure on the exhaust gas side should mean a higher concentration of oxygen and therefore a higher voltage compared to the voltage that would be present if there were no pressure differential.”

[AndyMc]

Mine is a home market import which doesn't have the O2 sensor. If it doesn't work I'll probably go for the carb conversion over the winter as I'm getting fed up with the flat spot and stutter. I've don't the sprocket job. I was very worth while even with no power upgrade.