Aftermath of rusting gas tank

[yappahgo]

Hey guys, I'm new to riding. I picked up a non-running GS500 on craigslist for a little under a grand. Here's the story:

Tha Party is a '99 (yellow) with around 14,000 miles. The guy who sold it to me is a Young Professional who put on ten thousand of those miles in the last three years. He's not mechanically inclined, but he garaged the bike and took it to a good mechanic for regular service. Last fall he brought it in with mechanical trouble, not running well, and the diagnosis was rust in the gas tank. He sent it out to the specialists for treatment - this isn't cheap, it's $500+ with the shipping factored in.

The gas tank is back, now sporting a sexy red coating on the inside, but of course the bike still doesn't run. The mechanic started it up a couple weeks ago and it flooded out (gas entering the combustion chamber, mixing with the engine oil). The mechanic quoted our Young Professional a few hundred dollars more for work on the carburetor, and this is where I come in. Beyond carb work, Tha Party also needs a clutch cable (some slack, not snapped), fork seals and a rear tire, so the Young Professional was looking at over $1000 to get his bike running perfectly, and sensibly decided to list it on craigslist and upgrade (after riding for three years, why not?).

So, I'm planning to rebuild the carbs, change the oil and start her up. My Clymer manual came yesterday ($13.33, used, on Amazon), and I have $100 of stuff coming on Monday from bikebandit: pilot jets, main jets and K&L Carb Rebuild Kits. (This forum was very helpful in giving me the confidence that I was ordering the right stuff in the right sizes. Thank you!)

Over the weekend I'll get the carbs off the bike, open them up and start cleaning. Hopefully I can get it all back together in the evenings next week once my new gaskets and things come.

My questions for the forum:

- does all of this ring true to you? The YoPro and the Mechanic seem like trustworthy guys, but you never know.

- given the tank rust problem, what would you expect to see inside that carburetor? Should I do anything differently from a typical deep clean?

- do you think I'm going to need any more carb parts? I don't have the needle jet tube or a jet needle coming, just pilot jets and main jets. Is it possible to order the needle jet tube and the jet needle individually? I've only found them as part of this Dynojet kit, but I'd rather go stock for now.

[BockinBboy]

I suppose if the gas tank was 'that' bad... rust would get into the carbs and foul things up, but there are ways to diagnose that before spending so much money on all of it...

I didn't really come to comment on the story, but will stay tuned to see what unravels.  On the carbs, no you don't want anything other than stock needles in there.  For some reason aftermarkets needles always cause problems... its one of the few things you HAVE to go OEM with... and hopefully your needles are fine (would take a lot for them not be) because otherwise they are around $50 each IIRC...

- Bboy

[adidasguy]

PJ Motorsports will do a professional cleaning of carbs for $75 plus parts. I could do my own but have other things I'd rather work on than carbs.

[The Buddha]

The buddha will do a clean and rejet of carbs for 50 parts and labor and shipping. Buddha also doesn't ruin parts just for the fun of it. Buddha likes old original parts ...

Unless it needs some industrial strength cleaning and thereby ruin parts ... much of the original will be preserved and the thing will probably be better than the new ... the K&N gaskets are crap ... they work fine, but they dont last too long.

Cool.
Buddha.

[The Buddha]

You're buying pilots and mains ... that's the first 2 things we toss in lieu of what the manual says was in the canada bound GS500 ... y'know where they dont have the EPA crap.

Anyway rejet kit for stock bike $25 shipped in US, carbs cleaned and everything installed etc ready to fit and run $50.

Cool.
Buddha.

[joweaver88]

$500 to restore and seal a gas tank? holy god almighty!!! You can buy a used, rust free replacement on ebay for ~$150 and the por-15 tank repair kit is $50 although I don't yet know how well that will work (I have a pretty rusty tank as well, we shall see).

[yappahgo]

Well, sheeit.... That replacement gas tank is pretty cheap, yeah. The Mechanic said it was shipped to California for the restoration. I wonder if the reasoning is to keep the gas tank original, keep it matching the color on the plastics...

I should be able to get into the carbs tomorrow. Have to go to the storage locker for tools.

I'll let you know what I find!

[yappahgo]

I got the carbs off today. Haven't got them open yet. This is what I can see so far.

http://imgur.com/a/6VUcm

[The Buddha]

Carbs are like fat chicks ... they are full of "Inner beauty" ...
Cool.
Buddha.

[yappahgo]

Made some progress. The new stuff arrived, and I've got the carbs opened up. Some pics: http://imgur.com/a/SkOuj

Questions:

(1) The mixture control screw ports are caulked over. Should I pull out the caulk, check and clean the screws?

(2) The new pilot jet looks very different from the old pilot jet. It has holes along the side, it's skinnier, and the tip has a larger countersunk pit. Did I buy the wrong pilot jets? Can I use these?





(3) Can I get the emulsion tube and slide guide out? I know from the carburetor parts sticky thread that they can come out, and my Clymer manual seems to suggest that you can get the emulsion tube out with a pair of needle nose pliers, but I don't see it happening. They're really stuck in there.

(4) I didn't find anything that would cause the engine to flood out (gas overflowing from the carbs into the cylinders), but the old gits are pretty grimy especially around their threads. Should there be a smoking gun? Should I just put them back together, change the oil, fire it up and hope for the best? The old main jets look the worst. Maybe they were the problem.

[yappahgo]

Hey, no responses so I'm going to go with my best guesses:

(1) The mixture control screw ports are caulked over. Should I pull out the caulk, check and clean the screws?

Leave them alone for now.

(2) The new pilot jet looks very different from the old pilot jet. It has holes along the side, it's skinnier, and the tip has a larger countersunk pit. Did I buy the wrong pilot jets? Can I use these?

Reddit helped me out with this one: No, I can't use these. New ones are on the way, but for now I'm going to re-use the old pilot screws, which look ok.

(3) Can I get the emulsion tube and slide guide out? I know from the carburetor parts sticky thread that they can come out, and my Clymer manual seems to suggest that you can get the emulsion tube out with a pair of needle nose pliers, but I don't see it happening. They're really stuck in there.

Most of the cleaning videos don't pull these parts, so I'll leave them alone.

(4) I didn't find anything that would cause the engine to flood out (gas overflowing from the carbs into the cylinders), but the old gits are pretty grimy especially around their threads. Should there be a smoking gun? Should I just put them back together, change the oil, fire it up and hope for the best? The old main jets look the worst. Maybe they were the problem.

Hopefully it's a good thing that the interior of the carbs looks ok. There is some damage to one of the needle valve float needles, a ring rubbed into the cone tip. I have new float needles. Hopefully the new main jets, float needles and gaskets will solve the problem.

[yamahonkawazuki]

Check with adidasguy, hes got alot of howto vids on youtube

[The Buddha]

The pilot jet is wrong. You cant toss in the ones with side holes in place of the no side hole ones.
Cool.
Buddha.

[yappahgo]

I just put the carbs back together. I think I found that smoking gun. The o-rings in the needle valve seats were quite decayed. They were sitting practically flush with the brass base of the valve seat. The valve seats were able to slide in and out of their sockets with no friction. I didn't realize this was unusual when I took them apart, but my "repair kit" included new valve seats and o-rings, and the fit was much more snug. Now I can see that the plastic float armature is actually supposed to seal the valve seat in against a bit of resistance.

This explains why the engine was flooding out. The flow of gas into the float bowls wasn't being restricted by the needle valve, since gas was able to make its way around the valve seat into the bowl. I'll post a picture of the valve seats tomorrow.

Tomorrow I'll put the carbs back on the bike, change the oil and fire it up!

[yappahgo]

It's still flooding over. Engine idles high to 5k rpm with some misfires. Misfiring increases gradually, then the engine speed bogs down and it stalls out.

It seems like fuel oversupply initially, then flooding out. I'm not sure where to to next with these carbs.

[lazyOCD]

Check your petcock vacuum diaphram. If it's leaking there will be gas in the vacuum tube going to the left cylinder. Cap off both ends and run with petcock in prime position. Other than that, float needles/seats and float height would be best bets. If you want to get out emulsion tubes take a matching thread screw and screw it in a little (where the main jet screws in), gently tap it and it should come right out ,there are some tiny holes that can be easily clogged. Leave the slides in place because there are some o-rings under them that I couldn't find a replacement for. Emulsion tubes won't cause flooding but they should be clean to function properly. Good luck

[yappahgo]

Thanks! I did take apart the petcock today. There's no problem with the diaphagm, but I that the petcock control valve was assembled all wrong. Of the three positions, (ON, RES, and PRI), *two* of them had access to the prime passage. When I got the bike, the steel indicator ring had ON at the top, FUEL toward the back, Res toward the front, and PRI at the bottom. Now that I have reassembled it in the only way that makes sense to me, it is rotated 180 degrees (PRI at the top, ON at the bottom, etc).

The tank-mounted petcock is also mounted incorrectly - the longer R nipple is toward the rear of the bike and the valve control knob points left instead of right. I wonder if someone thought this would make it easier to access the knob or something. It does eliminate the need for a long screwdriver, but you have to come in at an awkward angle to work on it.

Unfortunately, I don't think either of these issues could actually be causing the high idle, oversupply of fuel and flood-over. I tried to start the bike after fixing the petcock problem and routing the fuel lines correctly, and no joy. I cranked on it pretty hard yesterday and the battery is basically shot. I wonder if AutoZone will charge the battery, hmm.... if not, can I charge it with jumper cables from a car?

Next thing, I'll take the carbs off the bike, clean the emulsion tubes and play with the float heights, I guess. I got new needles and seats with my J&L carb repair kit, and the seats fit pretty snugly, so I think they're ok.

[yappahgo]

Photo post on imgur: http://imgur.com/a/x4CIv

These are the old needle valve seats, which I thought were responsible for the fuel oversupply. It made sense. With these sitting loosely in the carb body, gas could flow around the valve seats into the bowl.



The next thing problem I found was the petcock - In this photo, you can see the labels on the steel ring are rotated 180 degrees to where they should be. (For an example of the correct orientation, see this ebay posting.) I didn't realize it was wrong until I opened up the petcock. The prime passage was accessible from TWO of the settings - this will happen if you flip the knob around 180 degrees.



I've taken a few photos of the floats and the tang that holds the valve needle. They were initially set a bit richer than spec, so the last thing I did was to adjust these into spec (14.6mm +/- 1.0 mm). Directionally, it should help with fuel oversupply, but I honestly don't think that 2mm of additional fuel in the bowls would cause the needle valve to not close properly.






Finally, please enjoy this nice shot of The Aftermath gleaming in the sunlight. I really like this bike if I can only just get it running!

[bombsquad83]

Bad needle vavles for sure...get those replaced with OEM and you are on your way.  Make sure to check the float height with the clear tube method once you get the new ones.

If you want to clean the emulsion tube thoroughly, the best way to get it out is to push it out from the bottom.  Remove the main jet, and get a long screw or something that will fit in the hole where the jet was, but wont damage the threads on the inside of the tube.  Then just tap out the tube from the bottom.  You do not want to damage the top of the tube, because it's important that it keeps it's shape, as that is where the needle fits down in.

[yappahgo]

Dang...my K&L carburetor repair kits came with new valve needles and needle valve seats. Are these valve components known to be problematic? Where can I get the OEM ones? Is there a good way of checking that this is indeed the problem?

This is the kit that I got: http://www.bikebandit.com/k-l-economy-carburetor-repair-kit?m=22313