Hello everybody!

As some of you know from my add in the for sale section, I just picked up a neglected 2004 GS500F from a hack artist. I paid way too much, but I just love to fix broken things. I am an engineer by training, but a tinkerer at heart. I bought this one as a winter project. I have another 04F that I picked up this winter and it needed a motor so I put in a good used one from eBay. So now I have two 04Fs and at least one and possibly both will need to go to make way for new future projects.

Picture of the Yellow Bird (guess that'll be the bikes name from now on) below. Note the missing muffler, I don't want to know how loud it will be without it. I plan to put a stock exhaust on it.

The bottom two pictures show the carb in the state it was in when I got the bike. Can anyone point out the problems? (And no it's not the Pods though I do plan to change those out.) He said it ran before he put it away, I'm thinking he was fibbing a bit.

After a bit of carb cleaning and wiring issues I got the bike to fire up. Still doesn't idle right, but I need to get a new float bowl gasket for the left carb and drill out the fuel screws to richen it up a bit.

PS anyone have any good ideas for getting broken exhaust bolts out of the head? Fortunately they sheared with about 1/2 inch poking out so I can still get something on them, just hoping to avoid pulling the head.

I'm always excited to see a new project thread on the forum! Especially one where a GS gets rescued!

I don't have any tips on getting the broken exhaust bolts out... but I can say that per advice from this forum, I replaced the stock bolts with studs and nuts.

Looking forward to updates

I think you may have to bite the bullet and pull the heads to get the stud out. Too little space to work in. You could try ( if the thread exists on the remains of the stud) threading two pieces of square stainless 5mm and locking them together them turning them out with the inner one. Seen a rod welded to a stud at right angles but they tend to snap then the stud remains get harder to work with. Good luck with it. You could always get another head. Clean it up and mod it and change it over. I note you are in the US so getting a second hand head should be cheap and easy.
I found with my 07 project bike that the carbs are extremely finniky and had to clean then a few times before they were OK.
About to put a electric fuel pump/shutoff on mine to bypass the ridiculous fuel plumbing stock. I suspect that is part of the carb contamination problem.

Did you try running it with no air filters? The idle problem may very well be those pod filters. They likely have a "lip" on the inside that covers the little teeny orifices where air comes in for idle. I'd think it can't idle right at all with the pod filters like that (I have a pair!!). Your only choice would be to try to get it to "idle" by opening the throttle plate stop and getting air over the mid jet at "idle" which is choppy at best and more likely 3K+ before it'll be steady. That's how to make a three-circuit carb into a two-circuit carb.

Anyway, get a stock airbox on there and then start thinking about tuning.

You certainly need to drill the pilot adjuster covers and pull them but you won't be able to get the idle mixture right without rejetting. Upsize the pilot jet by one (I think in an '04 that's a #20) and maybe shim the needle with one washer to beef up the mixture on main? IDK much about these '01+ carbs. But I would highly recommend doing the procedure outlined in my blog post for refreshing the carbs with of course adjustments for the Mk2 carbs.

Mr. 72,

I am very familiar with your blog post about carburetor overhaul. I've read it a couple of times. Really good information. I ended up reading your whole blog (at least all those labelled as motorcycle posts). I liked the writing so much that I am tempted to look up a bit of your Si-Fi work to see if I like it too. I am on the hunt for a stock airbox as well. For now I just wanted to get it running and cleaned up before I started on the fine tuning.

Thanks for the feedback I was hoping you'd chime in because you usually look at things in a level headed manner that makes sense.

The current jetting is stock which is 130/60/17.5 which tells me the previous owner knew nothing about needing to rejet when changing things like intake and exhaust. I am almost happy to have to drill out the air screw because it means no newbie was in there messing things up before me.

Now that I have it running I'll check the valve clearances.

PS. Did you notice the float bowls were installed reversed (how are you supposed to do a float bowl fuel level check like that?) as well as the caps being installed backwards....the white diaphragm plastic doohickeys should be pointing the other direction.

Ken

Quote from: Kenner on January 09, 2018, 01:26:47 PM
Mr. 72,

I am very familiar with your blog post about carburetor overhaul. I've read it a couple of times. Really good information. I ended up reading your whole blog (at least all those labelled as motorcycle posts). I liked the writing so much that I am tempted to look up a bit of your Si-Fi work to see if I like it too.

music to my ears!


[you know my first book is free on Smashwords... fast reader will knock it out in 4 hours]

Now, on to practical matters:

You can set up the idle with no air filters. The air filter doesn't affect idle mixture at all. With the throttle plate [almost entirely] closed, the bike will idle with air drawn in through the holes near the bottom of the rim of the carburetor inlet. There's not enough vacuum to affect the "mixture" on the main jet.

With a #20 pilot jet you should be able to dial in the idle mixture just fine. Problem is going to become getting the bike fully warmed with it running with the pod filters, since riding it off idle is going to be a challenge. It probably runs like dog poo and is at risk of burning valves with stock jetting and those air filters. And like I say it won't idle right with those filters anyway. So you might be in a catch-22 until you can get your hands on a stock airbox. Might as well get a handful of o-rings and swap the intake boot o-rings while the carbs are not on the bike.

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Now that I have it running I'll check the valve clearances.

I'd do a compression check too if you can, since who knows how long it was run way lean with those pods and the risk of burning valves is >0 in that state.

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PS. Did you notice the float bowls were installed reversed (how are you supposed to do a float bowl fuel level check like that?) as well as the caps being installed backwards....the white diaphragm plastic doohickeys should be pointing the other direction.

nah. I saw the pods and jumped on that. Who knows what other issues backward float bowls cause. Maybe none. I know I have inadvertently put one on backwards on my bike before, but never both and put them on the bike that way They fit both ways. My guess is they function both ways. My guess is that on a single-carb bike it doesn't matter which way they run, just one or the other way to afford access to the bowl tap. But that's just a guess. I don't know this for sure.

And FWIW in case you didn't notice already, everything I say is from my personal experience and a bit of calculating on my part. I'm not an authority. I'm just a tinkerer with a year's head start on you.

Josh - that's why you can't sell your GS and leave the forum.  We need you and your smarts!!! 

Kenner - I don't think the orientation of the carb bottoms or the white discs affects how the bike runs at all.  There are a lot of carb parts that can go in either orientation, I suppose to save on manufacturing costs.  With some futzing and fiddling, looks like you can swap one carb body to the other side.

Use the 'heat spanner' on those seized studs, - A soak in CRC or similar - the longer the better, - a few sharp taps on the stud ends with a hammer to jar free the corrosion in the thread, then very carefully, with heat applied around the zorst port areas, see if you can ease the studs back and forward a few degrees with molegrips or stud remover. No use straining them too much by trying to turn them too far, you'll shear them, once they move a few degrees, then they'll come. But don't rush it, work them a little at a time, using CRC and heat.

+1 for soaking them and heat. If you can weld a nut on the broken bit, often the heat of welding is enough to help loosen them. If you do weld on a nut you can try turning them whilst gently tapping them with a hammer too!

Endopotential,

I believe your right that the orientation doesn't/won't affect how it runs. I was able to unscrew the caps and flip them both top and bottom. What it shows me is that a previous owner was such a newbie that he/she didn't bother to look up how to properly reassemble them.

This evening I had a bit of fun in the garage. I was able to double nut the two sheared studs, but they still didn't want to come free. I sprayed them with penetrating oil yesterday and hit them with a small torch today before trying to loosen them, but I couldn't jam one nut tight enough into the other to grip it strong enough to extract it.

Next I center punched the studs and drilled a small 3/32 hole all the way through them. I then enlarged the center hole to 1/8. This allowed me to spray penetrating oil up inside the head and hopefully work on the corrosion from the inside. Also the hole slightly weakens the bolt so it may help it give way. Tomorrow I'll try the double nut again. If that doesn't work I do have a Lincoln buzzbox 220 welder, but I fear to weld to an engine on a frame since the current may pass thru bearings or other things and possibly arc and score them. It really should be done with an acetylene torch, but I don't have one nor do I know how to use one. If the double nut doesn't work tomorrow I may just vice grip directly to the stud and try to wiggle it a bit.

I also played with the carbs a little more today. I need to order a couple of rebuild kits and give them the once over since at least one of the fuel valves is not sealing. I've had decent luck with the K&L kits from eBay.

One trick to share (as shown in the bottom image)is if one of those "cheese grade" JIS screws is stripped out, you can usually get it functional again by clamping on the screw in a vice and hitting the head with a hammer. They often fail due to a phillips screw driver caming out of the slot and bending the corners of the srew up. Pounding them back down usually makes it functional again. And remember Japanese bikes use JIS screws not Phillips screws. Save yourself some grief and buy a JIS set.

Ken

Sub'd!

Quote from: Kenner on January 09, 2018, 11:01:13 PM
If that doesn't work I do have a Lincoln buzzbox 220 welder, but I fear to weld to an engine on a frame since the current may pass thru bearings or other things and possibly arc and score them.

Ken

That isn't an issue, I have welded to several engines - including weld aluminum onto a savage motor. No issue welding a bearing shut, ever.
Cool.
Buddha.

Yellow Bird --> 2     Kenner --> 0

I put caution to the wind and trusted Buddha's suggestion and welded nuts to the studs. Then I hit it with heat from a torch and smacked the stud with a hammer to try to break it free but to no avail, unfortunately, they still did not come free. All that happened was the screw sheared again at the next thread in beyond the weld. I sprayed a bit more penetrating oil and I'll let it sit for another day and try again.  I have at least 2 more tries worth of stud. If that doesn't work I have backup plans 1 and 2. Plan 1 is I ordered a set of left hand cobalt drill bits which I will use to gradually enlarge the hole until either the stud comes out, or I have it large enough to run a tap thru to clean out the broken stud. Fortunately my pilot holes are centered pretty darn good so I am not too worried about eating into the aluminum threads with a drill bit. Plan 2 is use acid to eat out the bolt. I will drill it out until the holes are bigger and fill them with acid and let it do its thing. I learned about this trick from a website (named http://www.dansmc.com/) where an old school motorcycle mechanic from Idaho filled his winters with creating a free online motorcycle repair course. Lots of good stuff there. You should check it out. Namely his post about dissolving broken bits with acid http://www.dansmc.com/acid.htm

Now is just the waiting game. I have carb parts coming, I have the left hand drill set coming, and I have penetrating oil (hopefully) working its way under the stud screw.

Something to contemplate. The 2 bolts that sheared were both the inner bolts. The outer ones came out just fine. Is there a different stress or failure mode specific to the inner bolts to cause them to corrode in more than the outer ones? If any have sheared on you were they inner or outer?

Ken

Top pic nut welded in place.

Middle pic nuts sheared off.

Bottom pic nuts showing sheared stud inside.

Stainless bolts to replace them with aluminium grease should help ensure it doesn't happen again and just happen to look good as well.

Acid will eat the porus aluminum crap 100X as fast as the work and heat hardened steel bolt. Do not use acid, you're better off drilling and ez outing it.
I have done that to another bike and tapped the eaten up threads to a slightly larger SAE size.
Helps to take off the front suspension and crank the bike to the height with a winch or a tie down thrown over a tree branch or from the shop ceiling beam or something - it may be needed to where you can put some force on it when drilling the bolt. I'm trying to remember ho I cranked it up.
Cool.
Buddha.

Quote from: The Buddha on January 12, 2018, 01:23:37 PM
Acid will eat the porus aluminum crap 100X as fast as the work and heat hardened steel bolt.

how porous or how hard the material is has nothing to do with whether acid will dissolve it.

Sulfuric acid will dissolve the steel bolt readily while the oxide layer on the surface of the aluminum will substantially limit how much the acid can act on the aluminum. The ability of aluminum oxide layer that forms on aluminum in ordinary atmosphere to protect the aluminum from corrosion is a big reason for using aluminum for anything, it is very corrosion-resistant.

That aluminum oxide is aka "ceramic" and is very hard and corrosion resistant.

Just don't use hydrochloric acid. From what I read to dissolve steel and not aluminum, you should use 15% sulfuric acid.

OK well I've seen massive holes in cars and bikes near the battery so sulphuric acid will make mince meat out of the steel.
The engine is made of a mix of mystery metal, most of which is aluminum, so you may be mostly OK there too.
Good one mr72 thanks.
Cool.
buddha.

Quote from: The Buddha on January 12, 2018, 02:03:48 PM
OK well I've seen massive holes in cars and bikes near the battery so sulphuric acid will make mince meat out of the steel.

That it will. And hydrochloric acid will to. Or even vinegar (acetic acid), but only much more slowly.

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The engine is made of a mix of mystery metal, most of which is aluminum, so you may be mostly OK there too.

Yeah it's just an aluminum alloy. IDK if there's a steel cylinder liner. Also the valves are steel and there are other steel parts in there (the rings!) so I'd personally avoid getting any acid in/near the cylinder head.

Quote
Good one mr72 thanks.

Hey, you know someone had to pay attention in Chemistry class. I'm always down for hanging on to what is most likely useless information just for occasions like this.

Yellow Bird --> 3  Kenner --> 0

I tried welding nuts again and all it did was shear it shorter. So I went about drilling to holes a little bigger. I have them at 5/32 now and I used a small syringe to put a little bit of battery (i.e. sulfuric) acid down the holes.

If you follow the link I posted above the author explains (as did Mr72) that sulfuric acid will dissolve steel and leave the aluminum unscathed (muriatic acid, on the other hand, will dissolve aluminum and leave steel alone). You just need the right acid for the job.

I chose not to go with the left handed drill because I figured I would just break my bit trying to drill out the bolt since it is corroded in big time. Also, since it's a blind hole I was hoping the acid would fill the hole and free up the studs a little so an easy out can get purchase and remove it after it has dissolved a little.

If it comes out I'll clean the threads with a tap and install studs and nuts. If that still doesn't work I'll drill it larger and install a time-sert thread repair coil (I like them better than helicoils because they are solid with threads inside and out rather than a spring-like threaded coil).

I'll report on how well the acid did later.

Ken

Top pic, I steeply angled the bike so the acid would flow to the bottom of the hole.

Bottom pic. I sealed the hole with double sided tacky tape then poked a hole in it and squeezed in a little acid.

Quote from: Kenner on January 12, 2018, 03:05:32 PM
If you follow the link I posted above the author explains (as did Mr72) that sulfuric acid will dissolve steel and leave the aluminum unscathed (muriatic acid, on the other hand, will dissolve aluminum and leave steel alone). You just need the right acid for the job.

Careful. Muriatic (hydrochoric) acid will indeed munch steel like no tomorrow. BTDT.

By the way, muriatic acid, which is a low-concentration HCl available at pool supply stores, will also dissolve concrete pretty readily if you ever find yourself having to dig out a fence post footing. WOT I know.