Leaking Past

[brianinpa]

dan filipi » Mon Sep 23, 2013 11:42 am[/url]":3sek484f]
Your MPG will tell you a lot here about the carbs' condition and floats.
If they're leaking past while riding then your MPG will go down.
"Normal" (acceptable) MPG for the 1100 is at least 40.

I read this post on another thread and didn't want to hi-jack the OP's thread, so I am starting a new one of my own. Gerry and were discussing that he was smelling unburnt fuel while he was following me on our tirp to Joe's. Since that trip I have begun to use ATF in my fuel and so far I am not seeing any improvements. In fact, the opposite is true. I started out with 35 mpg and I was happy with that because I am not very gentle on the throttle, but since putting ATF in that first tank, I have seen a decrease in my fuel milage and I haven't changed my riding style. Four tanks and I have seen 34, 34, 33, and 32 mpg. So after reading Dan's post, and remembering Gerry's conversation on the same subject, I am thinking it might be time for a carb rebuild.

I guess my big hang ups to it are that in the 3 1/2 years I have had this bike, I have not turn off the fuel once and I have not had any problems with hydra-lock, so something must be doing okay in there. Additionally, what exactly is meant by leak past?

 

[dan filipi]

"Leaking past" I mean fuel leaking past the float needles while riding causing an over rich condition.

This may not be your low MPG cause.
Could also be weak slide springs letting the slides come up at the wrong time (early) which will also cause over rich.
Sticking slides too can cause over rich= lower MPG.

 

[dafox999]

When you hit a certain level air/fuel, your exhaust will start to turn black when you are rich. Additionally, dark coloring, such as heavy black wet or dry deposits on your plugs can indicate an overly-rich condition.

I've been getting about 35 on this bike for the few years I've had it. Dad got better mileage, but I probably ride a tad harder/faster.

 

[dan filipi]

Have to consider too that an overly lean mixture could also cause low MPG by reduced power which could mean having to pull more from the primary jets, bigger opening of fuel.
That too can usually be seen at the spark plugs insulator being white.

I don't think lean is the problem though Brian because you said Gerry could smell unburnt gas while riding behind you.

Heck for that matter your problem could be a weak spark causing overly rich, unburnt fuel.
Like we're finding with the C5, idle speeds up presumably because the fuel burn is better and at better timing to push those pistons faster.

These CV carbs are rather complicated.
Strange things happen when they're not working right.

 

[brianinpa]

dafox999 » Mon Sep 23, 2013 1:39 pm[/url]":2ln1jfho]
When you hit a certain level air/fuel, your exhaust will start to turn black when you are rich. Additionally, dark coloring, such as heavy black wet or dry deposits on your plugs can indicate an overly-rich condition.

I've been getting about 35 on this bike for the few years I've had it. Dad got better mileage, but I probably ride a tad harder/faster.

That is what I have always attributred my low gas mileage too: I like the way it sounds. :mrgreen:

Have to consider too that an overly lean mixture could also cause low MPG by reduced power which could mean having to pull more from the primary jets, bigger opening of fuel.
That too can usually be seen at the spark plugs insulator being white.

I don't think lean is the problem though Brian because you said Gerry could smell unburnt gas while riding behind you.

Heck for that matter your problem could be a weak spark causing overly rich, unburnt fuel.
Like we're finding with the C5, idle speeds up presumably because the fuel burn is better and at better timing to push those pistons faster.

These CV carbs are rather complicated.
Strange things happen when they're not working right.

When I changed my plugs before our trip to Joe's, they looked good and were tan. I guess I know what I am doing later tonight just to make sure.

 

[dan filipi]

Just wanted to say on the stock rack I was getting 42-43 mpg but idle smelled rich and plugs were a perfect light tan.

 

[brianinpa]

dan filipi » Mon Sep 23, 2013 2:07 pm[/url]":2u0fk5ge]
Just wanted to say on the stock rack I was getting 42-43 mpg but idle smelled rich and plugs were a perfect light tan.

Is that a form of tormenting me and my 32? :smilie_happy:

 

[mcgovern61]

brianinpa » Mon Sep 23, 2013 2:15 pm[/url]":2h5hrga9]

dan filipi » Mon Sep 23, 2013 2:07 pm[/url]":2h5hrga9]
Just wanted to say on the stock rack I was getting 42-43 mpg but idle smelled rich and plugs were a perfect light tan.

Is that a form of tormenting me and my 32? :smilie_happy:

:smilie_happy:

 

[joedrum]

with your gearing and bad carbs its a mpg nightmare

 

[dan filipi]

brianinpa » Mon Sep 23, 2013 12:15 pm[/url]":1gr2j3yq]

dan filipi » Mon Sep 23, 2013 2:07 pm[/url]":1gr2j3yq]
Just wanted to say on the stock rack I was getting 42-43 mpg but idle smelled rich and plugs were a perfect light tan.

Is that a form of tormenting me and my 32? :smilie_happy:

Sorry didn't mean it that way.
What I was suggesting was that even though the plugs are tan, it still smells rich so maybe the smell isn't a good indicator? Today's fuel maybe?

 

[brianinpa]

dan filipi » Mon Sep 23, 2013 2:19 pm[/url]":6v2or117]

brianinpa » Mon Sep 23, 2013 12:15 pm[/url]":6v2or117]

dan filipi » Mon Sep 23, 2013 2:07 pm[/url]":6v2or117]
Just wanted to say on the stock rack I was getting 42-43 mpg but idle smelled rich and plugs were a perfect light tan.

Is that a form of tormenting me and my 32? :smilie_happy:

Sorry didn't mean it that way.
What I was suggesting was that even though the plugs are tan, it still smells rich so maybe the smell isn't a good indicator? Today's fuel maybe?

I didn't think that you did Dan!

Today's fuel was another thought... I have a station that still sells 100 gasoline so I want to run a couple tanks of that and see what happens. Even still, I am able to get 140 miles before I have to switch over to reserve, so is that abnormal?

 

[mcgovern61]

I normally get 150-160 miles before I have to switch to reserve. If I am on roads (like 72) where you can go for a long time at 50-60 MPH, I can get around 175 miles before switching to reserve.