One cylinder too rich

[leafman60]

Dag nabbit, okay, why would my right cylinder be running richer than the left?? No PC installed. TB's synchronized, no leaking rubbers , idles great, runs great, butttt my right pipe is sooty and much hotter than the left

[pete roper]

While this doesn't sound like it is your problem it is worth remembering that because of the shared crankpin the firing interval on a Guzzi is not even. Power pulses occur at 270 and 450 degrees of the 720 degree cycle of the motor and this promotes a *lazy* cylinder that runs richer. This was such an issue with some of the later *old* smallblocks that Guzzi had to use different pilot jets, (Remember them ) in the left and right carbs to get them through the Californian emission regs!

 

Running much hotter would indicate leanness rather than richness to me or perhaps a mechanical problem rather than an FI related one. Just my 2c. I'm not an FI expert. Have you run a compression test on it?

 

Pete. (Sweltering at 39 degrees C and hating every minute! The only way to combat this is to replace ALL my blood with beer! Cold beer!!!!!!!! )

[leafman60]

Actually, richness would make the pipe/muffler hotter and sooty. The unburnt fuel carries the heat with it out of the cylinder and through the pipes, to grandmother's house we go.

[emry]

The unburnt fuel carries the heat with it out of the cylinder and through the pipes

 

I might agree with that but....

 

A lean mixture will produce a much hotter burn than a rich mixture thus the gas carrying the heat out the pipe will be hotter with a lean mixture, even if there is extra fuel in the rich mixture. During the burn process BTU's (heat) are absorbed by the fuel molecules which breaks the molecular bonds so that the molecules can recombine with our O2 and N to form a variety of other smaller molecules such a NOx and H2O. It is this process that releases engery in the form of heat. (Fire) When excess fuel is present it still absorbs some of the intial heat energy but never undergoes the combustion process of recombining. (No extra heat) Thus the net output of BTU is lower.

 

Proper dyno tuners use pyrometers to tune individual cylinders for the best power. A higher temp indicates a leaner mixture.

 

Trying to determine mixture ratio's using the soot on a pipe is a futile effort on a modern FI machine due to the variables used by the FI to adjust the mixture, particularly when a 2 in 1 in 2 crossover is used which causes sharing of the exhaust gaeses. (That why the put the O2 sensor in the head pipes.)

 

Gasoline Explaination .... Long but Detailed.

 

Technical explaination of combustion; not for the math faint.

 

And some where else I have seen an excellent explaination of the effects of rich lean ratio on the formation of combustion byproducts with the thermal engery calculations, and thus the temps but I can't find it. I will keep looking.

[docc]

Interesting about the 'lazy cylinder.'

 

Also not all synchronization procedures are the same. A motor synched at idle will be out at speed. "Guzziology" recommends balancing off idle. The shop manual instructs to then balance the idle with the air bypass screws.

 

Just an observation that the whole mess runs better with the air screws at a full turn ( instead of 1/2).

[leafman60]

Sheezaminny, black soot, gas smell most and "fuel cooling" usually means rich. But BACK to the question> rich or lean > why aint both dem dangs equal?

[Mike Stewart]

Humm, both my Guzzi= 4 pipes and all the muffler/ pipes always have soot on them and the spark plugs are a nice tan color. Now all my other bikes in the garage dont have soot (Aprilia, Ducati). I still think it is from the poor combustion chamber design.

 

Have you checked your valve adjustment lately?

 

That is my only suggestion.

 

Mike