Motorcycle running VERY rich.

[#8]

The exhaust that comes out is much too dark and the rim of the pipe is black with carbon.

The plugs were changed and the air filter is clean. Whats up with my bike?

[Big D]

change in temperature??, is your bike fuel injected or carburetter?

[#8]

2001 CBR 600 F4i (Fuel injected)

It ran rich all summer and continues to in colder weather. I dont understand why.

[Big D]

it might not necessarily be running rich, kinda sounds like your burning oil.
might be time to get new piston and rings??, get a compression test and find out.

[GYMBRAT]

what color is the smoke? if its blue its burning oil, if its black its burning too rich, and if its white its burning too lean.....EFI should compensate for all of these tho.....yeah get a diagnostics test done

[ironwill]

it might not necessarily be running rich, kinda sounds like your burning oil.
might be time to get new piston and rings??, get a compression test and find out.

This is the correct response....If its fuel injected, you wont be running rich.....
Good one Bigd....:)

[#8]

sweet. its good to have some riders on here that know the deal. im very appreciative.

[#8]

I just looked into that and it seems likely for sure.

What do you think about a possible fuel pressure regulator issue?

[GYMBRAT]

EFI can most def still cause your engine to run rich #8, or any of the fuel issues I have mentioned in my post as well. It wont cost a whole lot to get it "plugged in" and checked rather that throwing a rod through the side of your block ;)

again...what color is the smoke coming out of your exhaust??

[Forever]

I only know fuel injected cars so I'm not sure how much of this applies to bikes, but here goes.

Black sooty exhaust is usually a sign of rich air fuel mixture, bluish smoke it burning oil, and bright white smoke is burning coolant. The last one is not to be confused with normal light white exhaust on a cold morning which is just water vapor.

In cars the fi system receives data from an array of sensors which tells it how to mix the air and fuel. The MAF/MAP sensor measure the approx density of air coming into the engine and relays it to the ECU. Varying altitudes, temperatures etc can change the density of air and this information is needed for the ideal air/fuel mixture. The O2 sensor measures the burnt mixture after it is expelled from the cylinder and sends the information to the ECU which can be used to further adjust the mixture.

There is also a coolant temperature sensor. Internal combustion engines are designed to run at a specific temperature so when the coolant sensor tells the ECU that the engine is cold it will ignore the sensors and burn a predetermined rich air/fuel mixture at a slightly higher idle to help get the engine up to temperature faster. You may notice your car idles higher when its cold and you may even get a slight "gassy" smell.

Again, this information is based on a knowledge of fuel injected engines in cars and I have no actual bike specific knowledge.

Good luck figuring it out!

[gicantor]

I just looked into that and it seems likely for sure.

What do you think about a possible fuel pressure regulator issue?

Did it start running rich after the plugs were changed?

[BAM]

I have only owned carburated bikes.. \Sorry, can't help.

[#8]

Did it start running rich after the plugs were changed?

Its been running rich ever since I picked it up in July. The bike is relatively fine mechanically, and performs well for the most part, but it could be doing better.

Its a very fast bike that I expect more performance from. I really would like to diagnose and solve this problem as inexpensively as possible.

[Big D]

get someone to do a compresion test on it, that will tell you if you need new rings and pistons.

everything is pretty inexpensive if you can do it yourself.
you have any friends that are gear heads?

[#8]

oh yeah. weve completely dismantled most of the bike to do work on it over the winter. we have tons of tools and tons of free time coming up.

[GYMBRAT]

soooo then why not just rebuild it at the same time then?? :s

[BAM]

Probably a good first step on any bike would be a leak down test before you even get started diagnosing other problems
(if you are concerned with performance). Not that this relates to your immediate issue.

[Sandwiches]

start using Shell V-Power, son