Bandit Alley
GENERAL MOTORCYCLE FORUMS => GENERAL MECHANICAL & TECHNICAL => Topic started by: stefanoascari on June 06, 2012, 01:39:16 PM
-
Hi Folks,
Bandit gsf 400 91
I did an oil change a few weeks ago and ran the bike / let it sit for a while. Made sure the oil was at the correct level (full mark). Then I ran it for a few days and always checked back after letting it sit for a while: oil was at the line.
I checked again yesterday and the oil is way over the line. The only thing I can think of is the weather has gotten considerably warmer since the oil change. Could I have hurt the engine? The bike seems to be running ok-nothing unusual. I'm thinking to take the top of something like a Windex spray bottle, clean it, and use it to squirt any excess oil out through the fill reservoir.
Any ideas?
thanks
-
open the oil filler and smell or otherwise check for gas. It's quite common for a float needle to jam open and flood the crankcase with gas making it look like you have lot of "oil".
If that is what happened DON'T RUN IT! Drain the "oil", fix the carbs, put in fresh oil.
A
-
I have a suspicion you are correct as the oil smells like gas. The carbs have not been cleaned in 3 years according to previous owner (I bought the bike about 2 months ago). Is it a matter of cleaning the carbs at this point? Also, I should mention, previous owner used sea-foam.
Thank you
-
Yes, take the carbs apart and clean them. Pay special attention to the float needle & seat - and be sure the floats haven't taken on fuel inside. It's not that common, but I've seen it, and once you've found floats that make sloshing noises inside, it is something you tend to look at (listen to) anytime you have floats more or less in-hand.
-
when you pull the floats, look at the needle opening, but also down the side of the needle. Sometimes dirt will end up down the side and you'll have to fully disassemble the thing to get it out. What you want is the needles freely moving against their springs in the assembly. Invariably, you will mess up the float level while doing this, so be sure to check that.
-
Ok. So I'm trying to take the carburetors off the bike. What's the best method to take the throttle cable off the carbs? I'm afraid I'll snap the cable if I do the wrong thing as that's happened to me in the past.
-
honestly, I do most of my work with the cable still on, just work with the carbs right there on the engine.
That said, it's *way* easier to pull the carbs and then disconnect the throttle cable by unscrewing the adjuster all the way (small nut will drop out) and then it's free and you can monkey it around and get it out. it's a pain, which is why I mostly leave it attached....
A
-
Ok. I didn't know people do that. I'd be fine with doing it that way. How did you drain the bowls? Did you loosen the screw that's under them? I was tipping them earlier and a little gas leaked out.
Stefano
-
yes, drain them while still attached usually. I use a bit of clear tubing attached to the drain spout and draining into a little cup. after they are drained I loosen and the four intake clamps and pull them off. flip them over and wedge them into the frame (some cardboard or toweling might be appropriate depending on how much you care about the frame paint). Be careful, dropped screws tend to roll under the starter, or get jammed into the shock spring and other such horrible places.
A
-
How do I set the float level at the right height when I reassemble it?
-
working with the carb upside down (I actually just pull the whole float assembly and do it. If you look a little, you'll see that there are some tabs on the assembly that work as a measurement point), and the float sitting on the needle under it's own weight. The distance from the "gasket surface" of the carb body to the highest point on the float itself is the "float height". Stock setting is 15mm.
Now, people will tell you that you have to be very careful to hold the carb at 45 degrees so that the float doesn't compress the needle spring. But, on the B4, the floats aren't heavy enough to do this, so I don't worry about it too much. In fact, I actually measure *down* from the cross bar on the assembly. That is, from the tube that ties the two ends of the float assembly together. That thing sits at 24mm from the gasket surface, so 9mm down from there is the stock setting.
I'll see if I can put together a picture.
A
-
Oh wow. Sorry, that sounds really complicated...
-
Disclaimer: This is for a B12 - NOT (I repeat, NOT) a B4
Here is a picture showing float height setting. Pay no attention to the height specified.
(http://img7.imageshack.us/img7/1943/a17hsfloatheight.jpg)
-
I'm not sure what kind of petcock is on your bike but if it's a vac. like mine you should think about changing it or installing an in line shut off valve.This small mod can save you a lot of money and time as long as you remember to turn it off....good luck
-
"Now, people will tell you that you have to be very careful to hold the carb at 45 degrees so that the float doesn't compress the needle spring. But, on the B4, the floats aren't heavy enough to do this"
Not true, I had this exact issue the first time I rebuilt my carbs. Maybe different floats weigh differently but mine compressed the needle springs significantly.
-
I'm sorry. This seems to be going way over my head at the moment. Is this something that the carb cleaning walk through in the FAQ covers?
-
Lots of folks here eager to help out..... clarify your concerns and we'll attempt the same. :thumb:
-
Ok. Sounds good!
I have been able to detach the throttle cable. It's a bit of an odd place to reach around and grab. Putting it back will be fun. The carb set is now sitting on my desk. I will go purchase a carb kit and cleaner tomorrow.
-
"Now, people will tell you that you have to be very careful to hold the carb at 45 degrees so that the float doesn't compress the needle spring. But, on the B4, the floats aren't heavy enough to do this"
Not true, I had this exact issue the first time I rebuilt my carbs. Maybe different floats weigh differently but mine compressed the needle springs significantly.
On a B4? Interesting. This is the second one I've owned and third set of carbs. On all of them the floats have not been heavy enough to move the needle springs under their own weight. But then maybe I'm doing it wrong....
That said, I've seen other carbs on other bike models that *definitely* move the needle under the weight of the floats and one has to be really careful when checking this.
I'm due to pull them this weekend and I'll take some photos of how I make the measurement. I'd love to learn that I'm doing it wrong, if that's the case!
A
-
Ok. So I started opening up one of the carbs. How do I remove the float needle? It all looks so fragile I'm scared I'll damage something.
-
It's not quite as fragile as it looks.
you can remove the entire float assembly by lifting it straight up as one unit. It should be wedged in a little tightly by the o-rings that are in there (you'll see them after it comes out), but just pull. It will come out. You shouldn't have to actually remove the float needle from it's housing (part of the whole plastic float assembly) unless something has gotten stuck down in there.
A
-
Ok I was able to easily remove the float assembly. For some reason I thought I was supposed to pull the needle out too. Note of the floats look "stuck". I'm not sure what I'm looking for. The needles seem to work. If I'm not pulling the float needle out what is there to adjust when I'm re-assembling? This part is the only part that is confusing me so far. It looks like they just clip on. In all the tutorials I've found however people talk about measuring the height of the floats to the gasket base. I get that. What I don't understand is what exactly needs to be tampered with to set this height?
-
there's a flat metal "spring" that is connected to the floats and engages the float needle. This flat bit of metal is what you adjust.
A
-
Ah! I see. It's like a thin wire right? Do I use pliers to compress/adjust it?
-
The thin wire, which should form a rectangle is *not* the thing to adjust, but instead the metal tab that it wraps around. I'll try to get pictures tomorrow.
A
-
Ok Cool. I think I know what you mean. As for the float needle inspection, I notice these don't have rubber tips (they seem "bare"). What should I be looking for? The springs seem to pop back ok.
Perhaps I should purchase replacement floats for all the carbs to be safe? EDIT: It would seem I DO have to take the float needles out for inspection. Is this correct?
Thanks for all the help by the way!
-
Usually, if there is junk in there you can see it without actually removing the float needles from the assembly. honestly I can't remember if there are rubber tips on there or not. sorry.
Planning to tear into them tomorrow for my own work. I'll post pictures with arrows and such :)
A
-
Ok great. Thanks andrewsw. Also, a few other things:
- I can't get the emulsion tube out from the main jet. Are they supposed to fall out?
- I'm trying to understand how the floats interact with other components in the carb to stop fuel flow. As it is, it seems like they are simply there to float up and down but aren't connected to any other components. Am I not seeing something??
-
Okay, here are some photos.
They show the height adjusting tab for the floats. You just press on that a bit and it will adjust the height. They also show how you can measure the float height using the cross-member on the float assembly. If you look, you'll see that the assembly height from the gasket surface is 24mm. so for 15mm float height, measure down 9mm from the cross-member. Pretty straightforward.
Finally there is one showing the spot where stuff get's stuck forcing the floats to stay open.
I did experiment with my floats and confirm that *on* *my* *bike*, the floats do not cause the float springs to compress under their own weight, making it easy to measure them. Your mileage may vary.
- I can't get the emulsion tube out from the main jet. Are they supposed to fall out?
To remove the emulsion tubes, first remove the tops from the carbs being careful not to loose the tiny o-rings around the vacuum ports. Carefully lift out the spring, slide and needle -- watch out, lots of small bouncy parts. Flip the carbs over and remove the main jet. using an appropriate tool and care (brass parts!! Soft!! Be careful!!) press out the emulsion tube. The main jet screws directly into the emulsion tube, which is press-fitted into the plastic slide carrier. It should come out with a light tap or two. It may instead push out the slide carrier itself. This is fine, with that out, you can easily tap out the emulsion tube.
- I'm trying to understand how the floats interact with other components in the carb to stop fuel flow. As it is, it seems like they are simply there to float up and down but aren't connected to any other components. Am I not seeing something??
Hold the float assembly right-side up. The large of the two o-ring areas fits into the fuel inlet. When the fuel in the bowl is low, the floats fall down letting the float needle, sitting right under the float needle orifice (see the picture showing where stuff gets stuck) lower to open the orifice. Fuel can then flow into the float bowl. As the fuel level rises, it lifts the floats until they press on the float needle pushing it into the orifice and stopping fuel flow. All the rest of the fuel metering is done from the float bowl itself using the pressure differential between the engine and air filter sides of the butterflies and slides.
Hope this helps.
-
the other two photos...
-
Andrew,
Fantastic photos!
The explanation makes sense about the floats interacting with the needles. I did not realize fuel passed through there as it all looks so small.
- Do I need to remove the pilot jet and the enricher as well or do those stay? Is the enricher also called the "slow jet" ?
- I can't see any crud around the needle. How do I check for leaks?
-
I don't know what you mean by "enricher". There are two jets -- main and pilot. If you mean the "choke", not really a choke, but actually I guess it is an "enricher", then I don't know. I never mess with it because it's always worked and I never really need it anyway.
If you're just cleaning the carbs, then those two, main and pilot, should be sufficient.
-
Ok sounds good. I'll stick to those two then.
As for inspecting the float needles...everything seems fine but then again...I'm don't have a trained eye for these. The springs seem to pop back ok.
-
Then you're probably good. Once, just once, I had a piece of grit get down the *side* of the needle inside the housing and that was obvious -- the needle was stuck.
-
I see. Well, should I run a compression test or take the top end off and inspect gasket? What else could cause fuel to leak into the oil? I hope it was just a stuck float...this would be the second engine that dies on me within a year.. :banghead:
-
The single most likely cause of gas in the oil is a stuck float. any thing else is *way* less likely. Was there any bits of stuff in the float bowls? Sometimes it can stick the float open, but then get dislodged and move through. Or it could be still sitting in the fuel channels upstream from the floats. Lots of possibilities.
A
-
I saw some stuff around the o-ring for the needle seat but on the outside. I scraped it off. There might have been some stuff in the bowl. These passages are so tiny though. I'm going to soak the jets in carb cleaner and re-assemble. Hopefully it was just a stuck float. Is the pilot jet the one that is a set number of screws out?
-
Question. How do the floats go back in? I'm having a hard time pushing them back into place.
-
the screw that is a set number of turns out is the fuel screw, meters the amount of fuels through on of several holes all controlled by the pilot jet. The pilot jet is the small jet that recessed into the base of the carb next to the main jet. It's probably covered by a black rubber plug.
THe floats can be a pain to jam back in there. Be gentle and you can always let the clamping of the float bowl do it for you, provided the o-rings aren't crimped or anything.
A
-
Ok. Cool. The pilot jets are really stuck in there. Nothing is turning when I try to use a screw driver. I see people talking about setting the pilots to a number of screws out from bottom but these seem pretty stuck. Why is there a rubber cap on it anyway? Do I leave the fuel screw alone (I'm not sure which one is the fuel screw)?
Thanks again
-
Woah!
The pilot jets are located inside the float bowl alongside the main jet, recessed into a cavity. They are behind the black rubber plug. They should remove with a standard screwdriver (use care, brass is soft). Those should be firmly seated when properly installed.
The fuel screws are tiny screws set into a recesses on the engine side of the carb body right where the carb body and intake boots some together. They are essentially on the bottom of the outlet of the carb, where is meets the intake boots. They are *outside* the float bowls, on the engine side. They may be behind some kind of blank metal cover (mine have never had the cover, but mine have never been stock when I bought them). These screws meter the fuel for idle. These are the screws that are typically set some number of turns out (1.5-3 being typical I guess) from gently *gently* seated. If you pull them all the way out they will have a long taper on the other end, and there is a tiny tiny washer, o-ring and spring in there.
hope that helps.
A