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Discussion Starter #1
Hi guys. I've been getting under 30mpg on my bird, even as low as 24mpg. As it's a carb there is no FPR as far as I'm aware? I've changed the plugs but no difference. It has a full stainless exhaust. The temperature gauge always stays down on the cold mark even on long runs, it will only rise when sitting in traffic.
Does anyone know what could be wrong? It's getting annoying goin for a spin and consistently filling up!
 

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I had shocking MPG with a carb bird on full Remus exhaust. It popped a lot on engine braking. I would gte maybe 90 miles to a tank.
 

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Did it return better in the past or has it always been bad? What colour were the plugs when u changed them? If high milage, may be carb refurb time or choke sticking on.I assume there's no smell of fuel leaking?
 

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Discussion Starter #5
Did it return better in the past or has it always been bad? What colour were the plugs when u changed them? If high milage, may be carb refurb time or choke sticking on.I assume there's no smell of fuel leaking?
Plugs were ok looking when I changed them, a dark brown, there is 40k miles on it
 

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At 40k, would expect carbs to be ok, could be choke issue or maybe fuel tap leak into vaccuum tube? I'm too long away from carbs for any other suggestions, hopefully someone else maybe able to help? I do notice your sig says 2001 Bird tho, that is FI times? Also- you say stays in cold on gauge, from memory carbs do run colder than FI but would expect a bit higher so maybe not getting up to temp? Also, may not be fuel related- something silly like brakes binding?
 

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You want the plugs a light tan color to possible grey. Check the vaccum shut off valve at the bottom of the tank. It can start to fail and allow the system to draw fuel in through there causing a drop in mileage and rich run condition your seeing. The other possible culprit could be leaking needle seats in the carbs. Even at 10% ethanol it can raise cain with fuel system parts. a quick and dirty trick is to take a piece of clear fuel line about 12 inches and slip it onto the drain valve port on the bottom of the carb. With the bike setting on the center stand and running. Take open end of the line and hold it up. Leave a decent drop loop in the line and with the bike running open the drain screw. The fuel will fill the bend and should come up level with the parting line between the carb body and the bowl if the fuel level is correct.
 

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Plugs were ok looking when I changed them, a dark brown, there is 40k miles on it
Dark brown sounds a tad rich to me, 'light tan' is what you should be expecting (what I always used to look for when I checked any carb motor). I'm not a Bird Carb man so I won't make suggestions …..
 

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Discussion Starter #9
I reckon it's running rich alright as you can smell the fuel when running. I had a 01 bird and changing the FPR sorted the fuel issue on that but on the carb version I'm not sure what to do?
 

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I know it’s sounds crazy but many years ago I ran a K&N air filter (for about a week) on my 97 carbie with two bros slip-ons and not only did it run too rich, fuel mileage suffered dramatically (30mpg on a good day). I went right back to the OEM FILTER. I avg 38 mpg cruising 90mph on long highway hauls I can get as high as 43mpg depending on temperature, barometric pressure and humidity taken into account as variables. But again, 38mpg is pretty consistent for me on avg.
 

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Second the airfilter causing issues as well. But I'd check float levels. There used to be a pdf of the factory manual in the resources section. It might detail the clear line check I described. If the float levels look goos then you could have picked up debris in the fuel circuts. Best start with the vacuum port first on the petcock. It should be fuel free if not then that hqs has to be fixed first.
Let us know what you find and we can go from there.
 

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Hi. A bit of thread hijacking here... I wonder how or if this issue was fixed? O.P. hasn't followed up here, so I'm curious how this went down since I maybe have a similar issue with my 1998 BB. It's not that extreme in the fuel consumption, but still not very good, and smells a bit too much of gas from the right exhaust while riding. I have'nt been able to check the sparkplugs yet.
Thinking of hooking up a clear fuel pipe to the drain on the carbs as beestoys said to check if the floater valve is stuck. Since this is easyer than getting the sparkplugs out... Is there anything more to think of with this kind of issue?
(There is not any fuel in my vacuum tube to the petcock.)
Edit: I thought that I should smell the motor oil again today, I've done that a while ago and it was not smelly. So, I opened the oil fill cap and smelled it. Of course it was smelling of petrol/gas! :crap:
So, to clear out my different things to check and in what order:
1. Check floater valves as beestoys advised
2. Check sparkplugs condition and function
3. Check vacuum valve in the petcock
4. Should I check thermostat or is that not needed on a carbed bike since it has manual choke?
 

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Stell
It depends on the results if the 1st 3 checks. Let us know what you find.
 

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Discussion Starter #16
Hi. A bit of thread hijacking here... I wonder how or if this issue was fixed? O.P. hasn't followed up here, so I'm curious how this went down since I maybe have a similar issue with my 1998 BB. It's not that extreme in the fuel consumption, but still not very good, and smells a bit too much of gas from the right exhaust while riding. I have'nt been able to check the sparkplugs yet.
Thinking of hooking up a clear fuel pipe to the drain on the carbs as beestoys said to check if the floater valve is stuck. Since this is easyer than getting the sparkplugs out... Is there anything more to think of with this kind of issue?
(There is not any fuel in my vacuum tube to the petcock.)
Edit: I thought that I should smell the motor oil again today, I've done that a while ago and it was not smelly. So, I opened the oil fill cap and smelled it. Of course it was smelling of petrol/gas! <img src="http://www.cbrxx.com/images/smilies/crap.gif" border="0" alt="" title="Crap" class="inlineimg" />
So, to clear out my different things to check and in what order:
1. Check floater valves as beestoys advised
2. Check sparkplugs condition and function
3. Check vacuum valve in the petcock
4. Should I check thermostat or is that not needed on a carbed bike since it has manual choke?
Still in the process, cleaning carbs at the minute
 

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Hi. A bit of thread hijacking here... I wonder how or if this issue was fixed? O.P. hasn't followed up here, so I'm curious how this went down since I maybe have a similar issue with my 1998 BB. It's not that extreme in the fuel consumption, but still not very good, and smells a bit too much of gas from the right exhaust while riding. I have'nt been able to check the sparkplugs yet.
Thinking of hooking up a clear fuel pipe to the drain on the carbs as beestoys said to check if the floater valve is stuck. Since this is easyer than getting the sparkplugs out... Is there anything more to think of with this kind of issue?
(There is not any fuel in my vacuum tube to the petcock.)
Edit: I thought that I should smell the motor oil again today, I've done that a while ago and it was not smelly. So, I opened the oil fill cap and smelled it. Of course it was smelling of petrol/gas! :crap:
So, to clear out my different things to check and in what order:
1. Check floater valves as beestoys advised
2. Check sparkplugs condition and function
3. Check vacuum valve in the petcock
4. Should I check thermostat or is that not needed on a carbed bike since it has manual choke?
Make sure you change the oil before running her otherwise you risk bearing troubles
 

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Begin Edit:
I will add some more info! After the photos.
End Edit.

Hello again

Sure I won't be driving without changing the oil. (At the moment the oil doesent seem to be very diluted. But anyway I will not drive before changing oil.)

I have checked theese things:

1. Floater valves as beestoys described = They all seem to have the same level and not too high.
2. Sparkplugs = They all work as in giving spark, but they don't look very well. It seems to be oil on them. Please look at the enclosed pictures and give advice.
3. Petcock vacuum = Seems to be alright, I did some manual sucking through a new vacuum hose, and I did not get petrol in my mouth, only after much suck/blow I got a whif of petrol on the air. I will check this with a vacuum tester later when I get one. I don't think this is the thing broken after seeing the spark plugs.
4. Thermostat = I have not checked this yet.

Maybe it's time for a professional mechaninc to look at this now?

Pictures of the spark plugs:
Cylinder 1 DSC_1096.JPG Cylinder 2 DSC_1097.JPG Cylinder 3 DSC_1098.JPG Cylinder 4 DSC_1099.JPG

OK
Here's some more info I've come to realize is important.
So here's the history of the bike in my hands. It was sold as a 72 kW version here in Sweden, I think the first owner just got rid of the intake restrictors (or what they are called) because the metal parts of them are not there anymore, just the insulators marked with 72 kw. The first owner sold it to a friend who got sick, so he bougt it back, and then sold it to the person I bought it from a year ago. Sadly enough I did not buy from the first owner and by that I don't have the complete history of what they did to the bike at that moment of taking out the restrictors.

I bought it in beginning of April 2019. Drove it home about 500 km's. I thought it was using a bit much petrol, but I also understood that I'm not used to this bike. I was not really alarmed. But it smelled a lot of petrol fumes while driving slow or stoping at red lights. But I recalled my old Suzuki GS1000 from -82, which smelled a bit also, but not really this much tho.
I went out on some runs with my friends, they where complaining about that the biked smelled of raw petrol. So I started to search for the problem. I got to this forum and started to read about all fuel related problems I could find here. One of the things that was often mentioned was to check for petrol in the motor oil. So I did check that, and there where no smell of petrol in the oil. So I have been keeping on reading and checking stuff.
During this time I had a small accident were I drove really slow in a round about and braked to hard so I lost control and the bike fell over on the right side with the motor running. After that I kept on reading here and thought that maybe I should check the oil for petrol again. And this time it smelled of petrol. So I started to write in this thread to get som help.

So I showed this thread to my friend. He asked me if maybe the petrol in the oil comes from the accident when the bike were running laying down on the right side running havoc with all the vacuum hoses and such? And maybe the fact that I seem to have oil on all four spark plugs, comes from some release tube from the engine block to the air box? And that has been clogging up in the carbs and making it running rich?
As it happens there is oil inside the airbox around the intake to the carbs which seems to come from the foam surrounded hole in the back of the air cleaner box. But this is maybe normal?

One other thought I'm starting to entertain is that maybe the carbs has the wrong jets and settings for the opened up intakes?

It's starting to feel more and more possible that I have to jank the carbs and open them up for a checkup, clean and repair.

Where can I get a good repairkit for the bird carbs that ships to Sweden? I've seen that som are including new screws to replace the JIS ones, which seems really nice to get.
 
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