In-Line Fuel Filter Question and Carb questions / My introduction

[mr72]

I don't have an inline fuel filter. Bike had one when I got it and it didn't run correctly, I think the fuel filter had nothing to do with it but Watcher's probably right. Unnecessary and definitely a potential added restriction.

Drain your gas to get the gunk out, consider treating the tank to fix the rust. Worst that happens is some of the rust winds up clogging a carb. You're going to become an expert at cleaning these carbs, might as well use that expertise.

[Watcher]

I know that Watcher up above mentioned not to worry about an in-line fuel filter. What are your thoughts on adding one in, since my gas tank is getting rusty. Would it benefit or act more like a restriction? Or is it simply overkill for no reason?

Its me again, but I'll tell you my experience with them.  Living in the Midwest riding rain ror shine, commuting by bike, I needed to run all new fuel lines so I added a filter because why not.
A few months down the road I'd randomly "run out of gas" with plenty of fuel in the tank.  Usually letting it sit for a few minutes would cure it.
Eventually I was in a rush and on the side of the road I disconnected the fuel line above the filter.  The filter back-flowed a bunch of brown fuel and when I reattached the line it fired right up.  A week later same issue, same solution.

New filter, different brand/type.  Ran well.  A month or two later same issue.  The filter elements get clogged up and restrict fuel flow.

Said F it and ran a new line with no filter.  No issue since.

The carbs are sensitive to dirt/rust/etc, but so is the petcock.  There is no filter between the tank and the petcock, but people like to add filters between the petcock and carbs.
I say, if the screen in the tank works well enough for the petcock then the screen in the tank works well enough for the carbs.

One might say it's more important on a fuel injected system, I might say a fuel pump is susceptible just as much as the injectors.  The primary source of sediments is the tank and the pump is filtered...

Where I definitely would run a fuel filter is on an off-road bike in a dusty region, and I'd change that filter every oil change...

[Shift-E]

Its me again, but I'll tell you my experience with them.  Living in the Midwest riding rain ror shine, commuting by bike, I needed to run all new fuel lines so I added a filter because why not.
A few months down the road I'd randomly "run out of gas" with plenty of fuel in the tank.  Usually letting it sit for a few minutes would cure it.
Eventually I was in a rush and on the side of the road I disconnected the fuel line above the filter.  The filter back-flowed a bunch of brown fuel and when I reattached the line it fired right up.  A week later same issue, same solution.

New filter, different brand/type.  Ran well.  A month or two later same issue.  The filter elements get clogged up and restrict fuel flow.

Said F it and ran a new line with no filter.  No issue since.

The carbs are sensitive to dirt/rust/etc, but so is the petcock.  There is no filter between the tank and the petcock, but people like to add filters between the petcock and carbs.
I say, if the screen in the tank works well enough for the petcock then the screen in the tank works well enough for the carbs.

One might say it's more important on a fuel injected system, I might say a fuel pump is susceptible just as much as the injectors.  The primary source of sediments is the tank and the pump is filtered...

Where I definitely would run a fuel filter is on an off-road bike in a dusty region, and I'd change that filter every oil change...

Thanks for the heads up! Sounds like the filters are more maintenance work then they're worth. You'd need a bunch of them on hand to change rather frequently..

I didn't want to seem like I was ignoring your advice, just wanted to see if different people had similar/different experiences. Naturally, I assumed a member with a post count like yours knows what he's talking about haha

[Watcher]

...

I didn't want to seem like I was ignoring your advice, just wanted to see if different people had similar/different experiences.

Naturally, I assumed a member with a post count like yours knows what he's talking about haha

Oh not at all, but I did want to give you some sort of idea as to WHY I think they're unnecessary.

I've been around the GS a bit, but don't let post count alone lead you into blind belief of what we say.  I can and do get many things wrong, especially in regards to the updated 2k1+ GSs and their 3-jet carbs and oddball emissions control systems.  (I had a 1996 and a 1997)
Plus many of us have such a post count from the off-topic section...

[Shift-E]

So my parts have come in for my carb rebuild. Hopefully I can get to it next week.

Questions:

1) I know that I need to set the idle to 1200. Is that with the choke on, or released after it has warmed up?

2) I can't really set my idle. Since my tach is not working (mechanical tach, but newer engine that gives electronic signal as mentioned earlier), how should I be setting the idle? I dont know what 1200rpm sounds/feels like on the bike. Would anyone have a simple reference point for me to go off to get me as close to proper idle as possible?

[Watcher]

1) I know that I need to set the idle to 1200. Is that with the choke on, or released after it has warmed up?

2)  Since my tach is not working, how should I be setting the idle?

Best you can do is find a video of a warmed up GS idling and go by ear.

You can "feel it in", anything under 1200 and the engine itself may be loud or the RPMs will sound unstable, and within reason anything above will sound like it still has the choke on.  Its not super critical nor exact, just do your best until you get a proper tach sorted out.

[mr72]

1) I know that I need to set the idle to 1200. Is that with the choke on, or released after it has warmed up?

This is actually a much trickier question than you are suggesting.

But the short answer is, you need to set the idle with the bike fully warmed up, which usually takes about 10-15 minutes of actual riding on the road to achieve.

When you start the bike on choke, it should rev itself to about 5K rpm or so while the choke is on. Then after about a minute of this you can turn off the choke and go ride. The idle may be lower than you set it for a little while when it's cold. Eventually the idle will pick up to the preset speed once you get FULLY WARMED UP.

In my case for the first 15-20 minutes of a ride my idle speed may be 1K-1.2K and when it's all the way warmed up it might get as high as 1.4K-1.5K. If I adjust it do where it idles at 1.2K before it's fully warmed up then not only is the idle too fast when it's hot, but it also does the "hanging idle" thing. So the real key is to set the idle mixture and speed with a all the way fully warmed up bike. I prefer to put the tools in my pocket (my mixture adjustment screwdriver, special tool) and go on a 20-30 minute ride that ends up back at my house, then while the bike is still running from the ride, set the idle mixture and speed. This is the only way I've found to do it reliably.

[Shift-E]

Thanks guys!

One more question, about the tach. I was under the impression that wiring a digital tach in would be very difficult, but now i'm seeing it is actually very simple.

Correct me if I am wrong, but I would just need to splice in 4 wires? 1) 12v power. 2) ground. 3) power for the back light. And 4) splice in the signal wire to the right spark plug ignition coil, which will actually give me the rpm reading?

I'm trying to wrap my head around it all. I've done wiring for headlights in the past, but this is new to me and I've been trying to figure out where the newer tachs get their signal from. I've tried searching it on this site, but I always hit a dead end because I don't exactly know what it is that I should be looking for.

[Shift-E]

So how many turns does the air/fuel needle need to come out? The wiki says 2-4 (which is a huge difference). Manual says 2 and 1/4 for UK models, but "preset" for US models. What the heck is preset supposed to mean?

Am I right to assume, since i did the 40 and 125 jets like the UK models, that I should go for the 2 and 1/4 turns?

I've got the carbs almost off (didn't have a wrench handy yesterday to take the throttle cable off), so hopefully i'll be able to get it off and cleaned tonight. Just wanna know what I need to do for sure before I get into it. I've been reading and watching videos, so I'm pretty confident on how to tackle it.

[mr72]

So how many turns does the air/fuel needle need to come out? The wiki says 2-4 (which is a huge difference). Manual says 2 and 1/4 for UK models, but "preset" for US models. What the heck is preset supposed to mean?

Am I right to assume, since i did the 40 and 125 jets like the UK models, that I should go for the 2 and 1/4 turns?

You will need to adjust the mixture once you put it all back together. Start with 2 1/4 turns out and this will allow the bike to start.

Then (my quick instructions):

1. start the bike with the choke, and then go ride. Shut off the choke after about 2 minutes or so of running. Ride for 15 minutes or more to ensure the bike is fully warmed up. You may have to pull over and adjust the idle speed intermittently while you ride to keep it from stalling or surging.

2. when you get home from the warm-up ride, shut the bike off and put it on the center stand. Start it back up again.

3. Set the idle speed to about 1500 rpm or so.

4. Start with one carb. Adjust the idle mixture so that the idle speed increases. Keep turning the screw in whichever direction increases the idle speed until it stops increasing and begins to decrease, then move it back in the other direction 1/4 turn.

5. Reset the idle speed to 1500 rpm and repeat step 4 for the other carb.

6. Once both carbs are set, reset the idle speed to about 1200 rpm.

Now you should put your idle mixture tool in your pocket and ride the bike a bit with planned stops to tweak the idle mixture. When you come to a stop light or stop sign, note whether the idle returns to 1200 rpm rapidly or if it "hangs up" and takes a few seconds or more to return to idle. If it hangs up, then one or both, the idle mixture is too lean, and the idle speed is set too high. In this case, turn both idle screws out 1/4 turn and re-set the idle speed (it will only require about 1/8 turn or less of idle speed knob). Ride some more. Repeat this. Make sure the bike is FULLY WARMED UP. I personally found I was still tweaking this when the bike had been run up to an hour before I got it absolutely dialed. Season change here required me to make a minor adjustment to the idle speed alone.

That's how I do it Others likely can point to better instructions. But truly the key for me has been to understand two things: 1. you can't set the idle speed or mixture correctly until it is FULLY WARMED UP, and I mean, 15 minutes or more of actual riding on the road, and 2. the "hanging idle" is caused BOTH by lean condition AND idle speed set too high, so the solution is not always to enrichen, sometimes it's to just turn down the idle speed a touch.

Oh, and do a plug check after you ride for a while.

Gunson ColorTune or the portable wideband analyzer are awesome ideas for setting this better than my shadetree method. I don't have either tools.

[Shift-E]

Man, this is gonna be really tough to do without a tach lol

[mr72]

Man, this is gonna be really tough to do without a tach lol

Not really. You can do all of this by ear. In fact the "adjust until the idle stops increasing" is purely by ear. And someone with experience with riding a correctly tuned GS will be able to set the idle speed to ~1200 by ear. Hanging idle is a by-ear exercise as well. I only use the tach to verify my final idle speed.

[Shift-E]

I don't have that experience quite yet lol. With this being my first bike and I haven't even ridin it yet

But I am enthusiastic and optimistic so I will get it done! Currently looking for simple aftermarket tachs that I can use as a temporary fix in case I feel i need that reading.

[mr72]

I don't have that experience quite yet lol. With this being my first bike and I haven't even ridin it yet

Then in that case set it for 2 1/4 turns out on both carbs, adjust the idle speed WITH THE BIKE FULLY WARMED UP to a little faster than as low as it will go without stalling (it will idle at 5-7K with choke!!) then go ride and don't worry about it. Make friends with an experienced GS500 owner and tune it up later.

You don't need a tach and this convoluted idle mixture adjustment is not critical. US bikes from the factory had the idle mixture screws plugged with anti-tamper plugs and thousands of them are running around with untouched factory settings. Yours will be fine.

[Shift-E]

Then in that case set it for 2 1/4 turns out on both carbs, adjust the idle speed WITH THE BIKE FULLY WARMED UP to a little faster than as low as it will go without stalling (it will idle at 5-7K with choke!!) then go ride and don't worry about it. Make friends with an experienced GS500 owner and tune it up later.

You don't need a tach and this convoluted idle mixture adjustment is not critical. US bikes from the factory had the idle mixture screws plugged with anti-tamper plugs and thousands of them are running around with untouched factory settings. Yours will be fine.

This makes it so much easier haha. Thanks mr72! Hopefully I can have her running by the weekend

[Shift-E]

Good news, cleaned it up and reassembled everything. The kit did actually come with all the orings necessary, including the one for the fuel/air screw.

Bad news. How important is that little washer between the oring and spring on the fuel/air screw? One of them is missing...

The bike is all back together now, minus the gas tank. Tomorrow I'll try finishing putting it all on and firing it up while praying that everything worked.

[mr72]

Bad news. How important is that little washer between the oring and spring on the fuel/air screw?

100%    won't run even close to right without it.

[Shift-E]

You're joking, right?

[mr72]

You're joking, right?

Unfortunately, no. You need that washer. Find it. Not kidding.

[Shift-E]

FUUUUUUUUUUUUU