poor fuel economy BXTRS

DavidRutherford · Post by **DavidRutherford** » Sun Mar 22, 2009 10:28 am

Carburettors are like that. Some are excellent, some are crap. The setup of a carburettor is such a fine balancing act that there's no wonder you can have so much difference between two otherwise-identical setups.

kiwi · Post by **kiwi** » Sun Mar 22, 2009 8:26 pm

I think in my case its a two fold issue but still it does seem the less reliable starting BX is the Better for Fuel Consumption.

The second issue in the case of the TZS(91) v TRS(90) is relating to the speedo cable.
After checking against a Handheld GPS unit the 19TZS has a a 10% error made noticable with the rev count at 100kph (our legal limit). This error is less at lower speeds and the deduction of the reason is most likely relating to the composite material in the cable ends of the speedo!
The TZS has plastic ends which look as though they twist and distort where as the TRS has more solid ends.

Combine that in to the fuel calculations given the majority of driving is 100kph there still is a differance in fuel figures.

Basic trip for me is this out the drive onto to open road speedlimit (100kph) with two step hills in either direction. So the cars are both up to speed and temperature pretty soon.

Heres the best part have noticed that weather conditions play a part! With records for our none BX! Not quite sure how to explain that part or how humiditty levels impact fuel consumption.

Heck I should get a job on Top Gear with these studies

Post by **Tim Leech** » Sun Mar 22, 2009 9:55 pm

DavidRutherford wrote:Carburettors are like that. Some are excellent, some are crap. The setup of a carburettor is such a fine balancing act that there's no wonder you can have so much difference between two otherwise-identical setups.

My 16TRS is a pig to start when warm and coughs and farts intil its up to temperature, the GT which has the same carb and basic engine is totally different and starts first time and runs sweet everytime. the carb on the 16 has recently been rebuilt according to the history

DavidRutherford · Post by **DavidRutherford** » Sun Mar 22, 2009 11:41 pm

Roverman wrote: The carb on the 16 has recently been rebuilt according to the history

I suspect it's never been set up properly then. It's a bit of a lost skill these days to set up a carburettor just right. I can do it, but it takes me a remarkably long time to achieve, and I'm a lot better when I have access to a rolling road.

Post by **Tim Leech** » Sun Mar 22, 2009 11:52 pm

DavidRutherford wrote:
Roverman wrote: The carb on the 16 has recently been rebuilt according to the history
I suspect it's never been set up properly then. It's a bit of a lost skill these days to set up a carburettor just right. I can do it, but it takes me a remarkably long time to achieve, and I'm a lot better when I have access to a rolling road.

Agreed these days its all EFi and the days of setting a carb up by "ear" have gone. Once its warm its fine although the tickover is a bit changeable, fuel economys quite good and the emissions are MOt standard.

Post by **mat_fenwick** » Mon Mar 23, 2009 12:48 am

DavidRutherford wrote:It's a bit of a lost skill these days to set up a carburettor just right.

It's even more fun when you have multiple carbs to play with. And yet more fun when you've just rebuilt the engine and carbs on your bike, three days before a holiday, and now the f*£$#!& thing coughs and dies when you open the throttle more than a third. Apparently.