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-   -   '80 R65 Bing 32 float level (http://www.advrider.com/forums/showthread.php?t=893877)

rustygardhouse 06-08-2013 12:14 AM

'80 R65 Bing 32 float level
 
Yes, I'm going to flog this again...

Yes, I've read the other posts...

Yes, I've read Snowbum's article on float bowl fuel level.

I rebuilt the Bing 32 carbs on my '80 R65 & I'm now in the process of tuning them.

To help, I welded wide band O2 sensor bungs in front of the cross over tube so I can read the F/A mix using a AEM wide band F/A gauge as I motor around.

The AEM gauge has been very helpful.

Like everyone else, I've found the Bing 32 carb performance is very sensitive to float bowl fuel level.

& now the question:

Has anyone tried to set the float level on Bing 32 installed on a R65 using Snowbum's method?

I'm trying to set the level to 24mm as Snowbum suggests but the carbs are at such an angle, I'm spilling fuel out of the float bowl as I remove it from the carb.

I've also seen various measurements floating around:
- 22.5mm
- 23mm

Is Snowbum's 24mm right?

Or is this a set the fuel at a depth, balance the carbs & check the F/A mix by your favorite method.

One thing I have noticed is that if one carb is running slightly richer/leaner than the other, the power imbalance is clear on my homemade differential manometer as I rev the bike towards my balance RPM. The closer the carbs are tuned to the same mixture, the more power & less vibrations the engine has.

OK, cry havoc & loose the dogs of opinion!

Plaka 06-08-2013 08:15 AM

Quote:

Originally Posted by rustygardhouse (Post 21595906)
Yes, I'm going to flog this again...

Yes, I've read the other posts...

Yes, I've read Snowbum's article on float bowl fuel level.

I rebuilt the Bing 32 carbs on my '80 R65 & I'm now in the process of tuning them.

To help, I welded wide band O2 sensor bungs in front of the cross over tube so I can read the F/A mix using a AEM wide band F/A gauge as I motor around.

The AEM gauge has been very helpful.

Like everyone else, I've found the Bing 32 carb performance is very sensitive to float bowl fuel level.

& now the question:

Has anyone tried to set the float level on Bing 32 installed on a R65 using Snowbum's method?

I'm trying to set the level to 24mm as Snowbum suggests but the carbs are at such an angle, I'm spilling fuel out of the float bowl as I remove it from the carb.

I've also seen various measurements floating around:
- 22.5mm
- 23mm

Is Snowbum's 24mm right?

Or is this a set the fuel at a depth, balance the carbs & check the F/A mix by your favorite method.

One thing I have noticed is that if one carb is running slightly richer/leaner than the other, the power imbalance is clear on my homemade differential manometer as I rev the bike towards my balance RPM. The closer the carbs are tuned to the same mixture, the more power & less vibrations the engine has.

OK, cry havoc & loose the dogs of opinion!

A differential manometer does not show power imbalance, only vacuum imbalance. Vacuum correlates with power output, to an extent. The correlation can be better or worse and in all cases can be omitted by measuring power directly.

I was thinking of setting up O2 sensors in the holes where my cross over used to be. If you have a crossover you can be measuring mix from the far side, even upstream of the crossover (depending on how far upstream you went.) I may still do it, but I don't have a crossover and I'm less and less interested. I do plug chops to evaluate overall mixture. I still have the O2 sensors I was going to put in but I have to find the bungs I made.

The bike does not go down the road bolt upright. It does all sorts of angles and bounces around. So I don't bleed over float height. I set them parallel to carb body, per the manual, and let it go at that.

I do not vacuum balance. Tried it with various gauges, including a spendy and very accurate Walus differential manometer. I could just nail the vacuum, but when I checked the power output, it was off. Power balancing works better for a smooth engine. Simply make both sides put out the same amount of power working against the compression of the other side. It's simple, reasonably quick, and the gear goes in my on-board toolkit.

These carbs are simple to set up to run very well without lots of fussing. Sort of sad when lots of fussing and something to play with is what you want. BTDT. :D mebbe get FI and play with the mappings instead.


As a side note, my tiller has no float and bowl setup on the carb. Rather the carb is bolted directly on top of the fuel tank and there is sort of a cup/depression in a metal strap that gets splash filled with gas. That's it. The thing jumps around so much the cup stays filled and oddly enough it will even sit and idle w/o running the cup dry. It does have a choke, throttle, enricher , idle and main jet. Not a completely primitive carb.

guy152 06-08-2013 07:04 PM

I have the same problem, I think it's due to a more inclined carb angle on the r65...always been a pain to set. Bought bike new and noticed the carbs tops were tilted to the engine, always thought this was so to offset the incline, or slope angle from air cleaner to carb.

supershaft 06-08-2013 08:43 PM

A manometer does in fact show power imbalance. That is as long as the engine runs mostly on air. Hopefully around a ratio of 13:1 by weight. That's a lot of air!

23 or 24 mm? It all depends on how you look at the fuel wicking up your measuring devise. Adjust the float level on the bike to shut off just as the float is parallel with the carb body. Then take the fuel line off the carb before you remove the bowl. No gas will spill out. Measure the depth of the gas. THAT's how deep it should be. Do it a couple of times just to make sure you are consistant but you will be since that is the best way to set your float level.

guy152 06-09-2013 05:29 AM

I have tried several times, but it would overflow on my r65, changed floats and pins too, still would pour out, possibly there's a greater pitch angle to the r65?

guy152 06-09-2013 05:32 AM

Sorry, I was refering to the 23 / 24 mm, I will perform the float level to body technique today...thanks SS.

190e 06-09-2013 11:09 AM

I used to try and measure levels in the float bowl but you have to clamp or remove the fuel pipe to be sure of an accurate result. Maybe all the fuel in the pipe wouldn't empty into the bowl when the float drops but if it did the potential errors are significant. I calculated that the bowl holds approx. 46cc and and the fuel pipe holds approx. 7cc. that's enough to cause a 15 % error in the level measurement.

When I did those calculations I went back to setting them parallel.

One idea I did play with was to turn the fuel off a little way before reaching home. If you get it right so that the fuel pipe is just empty and the idle speed has not yet dropped (the idle speed will drop long before you feel a loss of power at a steady cruise) dropping the bowl will then give a more accurate reading. Not suggesting this as a way of setting the floats but you do learn something about how float level impacts on engine running.

supershaft 06-09-2013 02:43 PM

Quote:

Originally Posted by guy152 (Post 21602433)
I have tried several times, but it would overflow on my r65, changed floats and pins too, still would pour out, possibly there's a greater pitch angle to the r65?

I am talking about a R65. There's no difference doing this form any other model.

rustygardhouse 06-15-2013 11:53 PM

OK, I'm back
 
So, I dropped both float bowls, took them to work, futzed a round a bit & marked the front of the bowl with dimples at 1mm increments form 21mm to 25mm.
http://i1078.photobucket.com/albums/...2dimples01.jpg

Now when I take the bowl off, I easily tell the changes I've made.

As a note, there was a 0.3mm difference between the edge & bottom of the bowl between the 2 bowls. With this kind of variance in the parts, I use the dimples as a relative measure, not absolute.

http://i1078.photobucket.com/albums/...uellevel01.jpg

I also remove the air manifold, shut the fuel off & remove the fuel line then cock the carb in the gasket so the bowl is as near to level as I can get.

http://i1078.photobucket.com/albums/...edcarb01-1.jpg

I put the fuel line just over the end of the fuel inlet barb on the carb, hold the empty bowl on the carb, turn the fuel on, turn the fuel off, remove the fuel line & let the excess fuel dribble into a catch bowl and finally remove the fuel bowl straight down. I do 2 measurements to make sure I'm not spilling anything.

Anal? Well, maybe just a touch.

I warm the bike up, rough set the idle mix & balance using my O2 sensor & home made differential manometer then balance the carbs at 4k rpm.

The bike goes for a 8 km ride & I do the idle mix on both sides with the O1 sensor & balance the carbs at idle & 4k rpm.

I then take the bike for a run & watch the O2 sensor through the rpm range then I swap the O2 sensor, ride the same route & check to check the other cylinder.

Here's what I've found so far:

- the carbs are very sensitive to fuel level
- the float tang is not very sensitive to bending and easy to dial in any level I want
- with the O2 sensor & manometer, I can dial the idle in to a purr at 900 rpm & 13.5 F/A mix
- there is a big difference between O2 readings on the stand & on the road
- when riding around, the O2 sensor clearly shows the change points between the 3 jets.
- the 02 sensor clearly shows if a cylinder is running lean
- a cylinder may have an OK A/F mix through the needle valve range but become very lean in the main jet range

A low A/F mix can be caused by two things: a proper throttle valve opening & too low a fuel level in the bowl or the throttle valve not opening enough & the cylinder being dragged by the other one so it 'looks' lean. I stumble on the latter case because I thought I had balance the carbs but one was running lean and when I rechecked the balance, the lean cylinder needed the throttle valve to open a bit earlier.

Inch by inch, I'm getting closer.

As a side bar...

The reason I've got the time to play with this is that on Jan 5 this year, I was blindsided in a car park. A 5kph 'bump' left me with a plate & 9 screws holding my right tibia together & a criminal distracted driving charge for the other driver.

The bike? Since the accident was at such a slow speed, I was able to gently lay the bike down on it's left side. A bunch of 'normal' scratches from that move but that's it.

I'm 50% weight bearing which I take to mean that if I can drive my car, I can take the bike for short 'test' runs.

Oh, the guy who towed my bike managed to bend my handle bars. Now THAT took talent!

ME 109 06-16-2013 01:08 AM

Quote:

Originally Posted by supershaft (Post 21601147)
Then take the fuel line off the carb before you remove the bowl..

Correct to my way of thinking too.

I take a different approach to float level tho'.
Fuel on boots, float too high.
Sports bikes in front instead of behind, float too low.

Plaka 06-16-2013 01:26 AM

Quote:

Originally Posted by rustygardhouse (Post 21654333)
So, I dropped both float bowls, took them to work, futzed a round a bit & marked the front of the bowl with dimples at 1mm increments form 21mm to 25mm.


Now when I take the bowl off, I easily tell the changes I've made.

As a note, there was a 0.3mm difference between the edge & bottom of the bowl between the 2 bowls. With this kind of variance in the parts, I use the dimples as a relative measure, not absolute.



I also remove the air manifold, shut the fuel off & remove the fuel line then cock the carb in the gasket so the bowl is as near to level as I can get.



I put the fuel line just over the end of the fuel inlet barb on the carb, hold the empty bowl on the carb, turn the fuel on, turn the fuel off, remove the fuel line & let the excess fuel dribble into a catch bowl and finally remove the fuel bowl straight down. I do 2 measurements to make sure I'm not spilling anything.

Anal? Well, maybe just a touch.

I warm the bike up, rough set the idle mix & balance using my O2 sensor & home made differential manometer then balance the carbs at 4k rpm.

The bike goes for a 8 km ride & I do the idle mix on both sides with the O1 sensor & balance the carbs at idle & 4k rpm.

I then take the bike for a run & watch the O2 sensor through the rpm range then I swap the O2 sensor, ride the same route & check to check the other cylinder.

Here's what I've found so far:

- the carbs are very sensitive to fuel level
- the float tang is not very sensitive to bending and easy to dial in any level I want
- with the O2 sensor & manometer, I can dial the idle in to a purr at 900 rpm & 13.5 F/A mix
- there is a big difference between O2 readings on the stand & on the road
- when riding around, the O2 sensor clearly shows the change points between the 3 jets.
- the 02 sensor clearly shows if a cylinder is running lean
- a cylinder may have an OK A/F mix through the needle valve range but become very lean in the main jet range

A low A/F mix can be caused by two things: a proper throttle valve opening & too low a fuel level in the bowl or the throttle valve not opening enough & the cylinder being dragged by the other one so it 'looks' lean. I stumble on the latter case because I thought I had balance the carbs but one was running lean and when I rechecked the balance, the lean cylinder needed the throttle valve to open a bit earlier.

Inch by inch, I'm getting closer.

As a side bar...

The reason I've got the time to play with this is that on Jan 5 this year, I was blindsided in a car park. A 5kph 'bump' left me with a plate & 9 screws holding my right tibia together & a criminal distracted driving charge for the other driver.

The bike? Since the accident was at such a slow speed, I was able to gently lay the bike down on it's left side. A bunch of 'normal' scratches from that move but that's it.

I'm 50% weight bearing which I take to mean that if I can drive my car, I can take the bike for short 'test' runs.

Oh, the guy who towed my bike managed to bend my handle bars. Now THAT took talent!

I would use the word "compulsive" before I would use the word "anal". But I would also be using it in a very technical sense. Completely on the other hand, there is much fun to be had just screwing around with the stuff for the sake of it. Nothing wrong with that. Bikes are supposed to be fun.

I think you may be closing in on the problems with your AF monitor and manometer. You can dial in the AF ratio to the Nth and match both sides precisely, and match the vacuum as well to the resolution of your equipment, but this has little to do with how the motor runs. The two sides of the motor are in no way equal. Not it displacement, compression, component weights or accelerations, friction, intake and valve characteristics, carb dimensions and operation...nothing. So spitting hares trying to measure correlates of the thing you want, equal power delivery from each side, can lead you far astray.

On any given day air velocity will correlate to air pressure, but do you think those two carbs are both working with the same correlation coefficient? If it's well built, you manometer will. You have a variable jet in that carb responding to air velocity, and it don't respond the same way on both sides. Match the velocities/pressures--- you have not matched the fuel delivery. This should show up on your AF monitor.

No, it don't work the same way on the road as on the stand. If you wonder why, just find a pond and toss a rock in it. Then think about the depth of the fuel in those bowls again---on the road. If you want a lot of accuracy then you go to FI, not carbs. (Which is of course where everyone has gone).

What's with leveling the bowls to do fuel tests? Do the carbs sit like that when driving? (I sure hope not!). You are evaluating a situation that never occurs 'in the wild'.

Like the little marks. But you need to hold that bowl dead level in two axis to use them. Probably need a fixture you can level out ahead of time, then hold the bowl up under it---at which point you could use a simple sliding gauge to measure the depth.

But there is another way to play it. Make two marks about a mm or so down from the lip at either end of the long strait side of the bowl. Each exactly the same distance down. Use a square and just scribe---or even scribe a line all the way across.

Now the surface of the fuel in the bowl is always perfectly level, no matter what the bowl is doing. So you tip the bowl towards your scribe line until the fuel just touches all the way across---you will see the meniscus jump when it touches the scribe. Then just measure the angle of tilt of the bowl with a digital level (many of them measure angles off an internal pendulum, accurate and not too costly).

What would be slicker than snot of course would be a regular level tube. Like you see on the front of those big Bunn coffee pots. You have an un-used jet bore on one side of the bowl and only a tiny hole is needed to the inside. Get some glass tubing from your local hash pipe maker (ask around at head shops) or any anyplace that has chemistry stuff (like for kids---some hobby shops). Keep the tube large enough to avoid capillary effects. Now you need to drill a hole in the outside of the bowl at the jet bore and interface that with the glass tube. The glass is easy to bend and work (like flaring it) so I would probably just bring out a brass tube stub, secure it w/ 290, then bend the glass into a J tube and glue it to the brass as well. Or maybe something with silicone fuel tubing from the hobby shop...depends on the glass I suppose. Now you measure the absolute height of the fuel w/o the rundown from the fuel line or the carb internals above the needle valve. Probably just make one from an old bowl and use it to set both sides, the bowl bodies are the same---which bore that starting jet is installed in is lefty righty.

Fuel flow is dependent on pressure which is turn is dependent on the level in the gas tank (all filters and valves being adequate). Valves, like switches, have hysteresis. When the valve begins to close, it does not close at the same height every time...or at the same speed. Lots of fuel in the tank means more pressure against the needle valve and more force required from the float to close the valve---which requires more submersion of the float--ie, a higher fuel level. (Well, you wanted to get anal...)

The jet circuits overlap. So it one site is running lean and you open the throttle valve a bit (per your description) then you are adding more air--leaning it further----unless you are well into the midrange and running mostly on the needle jet at which point opening the butterfly will increase the air velocity in the venturi, raising the slide and needle and allowing more gas---except with the slide raised you are adding more air---around and around. This is why these carbs can compensate to a good extent for altitude and weather changes in the mid range. Very different story at idle or at WFO running primarily on the mains. This is also why a very simple tuning routine works so well. If your basic jetting is correct (and the AF monitor is quite helpful there---except the correct jetting is well known unless you have done some major mods) the other 3 settings fall in line. Not a lot to play with :(:

When you measured the depth of the bowls, did you include the gasket? Guess where all the variation is---never mind the mounting each time. But what matters is the distanc between the top surface of the fuel and the bottom of the main jet. This determines the pressure at the main and needle jets (on the stand of course). If the bowl continues 6 feet below the bottom of the main jet or only 4 mm it makes no difference.


The AF monitor or a differential thermometer (I am using the later) is handy for picking up things like a leaky choke or an ignition issue. Can be hard to tell which---ignition is the easier to test. On a two plug if one coil is getting weak or a wire conductance is changing or a plug is eroding...

One game to play depending on the trip is to lean the main to save fuel. Get closer to stoch. The idea is you are only really on it at speed and there you have the cooling to handle it. You can also lean the idle to an extent. it'll idle like crap but on a road trip you don't idle much. This also leans out well into the midrange which should be fast enough for cooling if it isn't real hot out. Good game if you can't really run fast.

Despite razzing you I enjoy hearing about your adventures.

Bummer on the idiot in the parking lot.

When you drive your car, do you have to put your foot down to stop--I mean really put it down hard because you just had to stop fast to avoid some idiot and didn't get to chose which way the bike was leaning or which foot to put down?

Just wondering.

Plaka 06-16-2013 01:41 AM

Quote:

Originally Posted by ME 109 (Post 21654469)
Correct to my way of thinking too.

I take a different approach to float level tho'.
Fuel on boots, float too high.
Sports bikes in front instead of behind, float too low.

Must have some pretty lame sport bikes down there. Even an old 600 sportbike will dust an airhead. (so would my K bike) And even more so in the twisties. Not so good on the longer courses tho'...more than 500 miles and somehow they fade away.

supershaft 06-16-2013 11:47 AM

Reading snobum AND Plaka? Seriously?

Sport bikes and airheads? Plaka is forgetting that someone has to ride them. He is also forgetting or probably has never known that, for the most part, the fastest bikes have the slowest owners. Besides, I guarantee that my airhead will leave his old K bike behind anywhere. Yes, K bikes do handle better in some senses and others they don't. Hauling ass wise? I would rather have an airhead. If only you could make that extra 100lbs disappear, then it would be a different story.

190e 06-16-2013 12:59 PM

This is a really interesting thread - at least when it sticks to talking about carbs.


Rusty

When you say the carbs are very sensitive to fuel level I always think that the most important thing is that the levels are as equal as possible for both carbs. So from your observations just how close to equal do they need to be. 1mm or less ?

Also from the same observations did you notice that the sensitivity to level varied at different throttle openings ? In other words if you have a level difference between the carbs where does it have the biggest impact.


For what It's worth I think 24mm is a touch high and tend towards 22 - 23mm


Supershaft.

It's quite a few years back but you used to say the level was 22/32nds on your machinist rule which = 22.2mm

and ME 109 quipped:

28/32 isn't being too exact but 56/64" is !!
I like to set mine at 7/8"


Interesting topic carb levels.

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ME 109 06-16-2013 01:08 PM

Quote:

Originally Posted by 190e (Post 21657305)

and ME 109 quipped:

28/32 isn't being too exact but 56/64" is !!
I like to set mine at 7/8"




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You remember that?! :D That was a hundred years ago.


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