Carb Overflow with All New Parts

[Guest]

Hi guys. I have a 1980 GS750 that I've been working on. I installed all new needles and seats, as well as all new stock jets and gaskets. After getting everything back together the carbs were overflowing from the air jets, and the overflow tube in between carbs 1 and 2. I've set the floats at 22.4mm per the manual, and have even gone higher to try to solve the problem. I've also replaced the new needles / seats on these carbs with the originals (originals were suspect). Still, the carbs overflow. The petcock is brand new, and is working as it should. I've also tried hooking the fuel line up to a standard fuel tank with no valve, and the carbs overflow as soon as the bowls fill up.

I don't remember where I purchased the carb kits, but i think it was either Partsnmore, or Z1. They were aftermarket kits, and I think they were KL, but i don't remember for sure. Has anyone else had bad experiences with the aftermarket needles/seats? They don't have rubber tips, but neither did the originals. I really don't want to spend over $30.00 a piece on OEM pieces, especially after buying all new kits. Any thoughts on the aftermarket pieces? Is there something else I'm missing?

Thanks,
Josh

[wildeye]

make sure you are not setting the floats with a gasket in , gasket must be out, make sure vents are not blocked , and recheck heights , i know i just went through the same thing >

[Steve]

After getting everything back together the carbs were overflowing from the air jets, and the overflow tube in between carbs 1 and 2.

First of all you have NO overflow tube ANYWHERE, let alone between carbs 1&2. That is a VENT hose, not an overflow.

By the time fuel comes out there, it will also be flowing freely down the throats, into the intake ports, past the open valves, past the rings and into the oil. Please change your oil before starting the bike.

I don't remember where I purchased the carb kits, but i think it was either Partsnmore, or Z1. They were aftermarket kits, and I think they were KL, but i don't remember for sure. Has anyone else had bad experiences with the aftermarket needles/seats?

Sorry, but your first mistake was buying "carb kits". The proper way to refurbish your carbs is to strip them down completely, soak each carb in "dip" for about 24 hours, then re-assemble them with new o-rings from cycleorings.com. Just to make you cry a little bit, that kit costs about half of what you paid for ONE of your carb kits.

There is a good chance that your fuel leak is from the o-ring around the float valves. If you don't lubricate them when installing them, they stand a good chance of deforming when forced into place.

.

[Newell33]

Haha... Thanks for the welcome... Yes, I understand it's a vent tube, but how about I call it an overflow tube in this instance? Two of my carbs were completely gummed up to the point that I couldn't get them clean, especially the pilot jets. I also had three bad rubbers in the float bowls, so I decided to go ahead with all of new parts. I just recently rebuilt some GPZ550 carbs with aftermarket parts with success, so I expected the same with this bike. I always lubricate o-rings with a small amount of silicone grease prior to installing, and that was the case with these carbs as well. All four floats float, so I'm curious if there's been any bad luck with aftermarket needle seat assemblies. I plan to take another thorough look again, but wanted a few opinions prior to replacing them again.

[Steve]

There are many here who are rather vocal about NOT using aftermarket parts for carbs or brakes, but I am not one of them. I have used float valves from Parts-n-More many times, have not had any problems with them.

If you understand that it's a vent tube, why confuse the issue and call it something else? The older VM series carbs did have overflow tubes, but your BS-series carbs do not.

"Completely gummed" carbs are the exact reason that we strip and dip them. You would be surprised how they would turn out, when done properly.

Just because the floats float doesn't necessarily mean that they float at the right height. After setting an estimated height with calipers, it is best to follow up with a wet test. When the carb is assembled, insert a modified drain screw that has a nipple attached. With a piece of clear tubing on the nipple, hold the tubing up the side of the carb and add gas. You will easily see the actual height of the fuel in the tubing.

.

[Newell33]

Steve,

I appreciate the help. I managed an auto parts store for many years, so I heard all kinds of names for all kinds of parts. I'm not going to worry about vent tube vs. overflow tube. I knew what it was, and didn't think before I typed. No need to get hung up on it. All that does is steer people away from people like you that have knowledge to share. I also understand the differences in OEM and aftermarket parts. Sometimes there's a lot of difference in quality, and sometimes the aftermarket parts are made by the same original equipment manufacturer. Although I've previously had good luck with aftermarket parts, I know others haven't with other makes of bikes.

I'll take your advise and check the levels using the clear tube method when I'm able to spend some more time at the shop. This isn't rocket science, so it shouldn't be too hard to track down the issue.

Thanks,
Josh

[Nessism]

K&L carb kits are decent. I doubt the problem is related to those parts unless something else is wrong. For example, maybe the float needle is a different height so that means the float needs to be adjusted to work with the new needle. At any rate, sounds like something fundamental is wrong. Maybe try removing the float bowl and seeing if the flow stops when you manually lift the float? The clear tube trick to measure fuel height is a good idea but if fuel is reaching those vent hoses, you have a drastic overflow situation, not a minor one related to float height.

[chris032188]

Idk if this would help you but it did help me check to see if my oring was leaking on the needle seat. I put a little fuel into the side of carb where fuel flows in while holding the float closed.

[Steve]

I'm not going to worry about vent tube vs. overflow tube. I knew what it was, and didn't think before I typed. No need to get hung up on it. All that does is steer people away from people like you that have knowledge to share.

I'm not worried about it, either. Just found it curious that you say you knew what it was, yet called it something else. Now that you have shared your background in auto parts, it's even MORE confusing. If it steers you away, ... oh, well.

Your profile and post count say that you have just joined recently, so you don't really have a feel for the general attitude on the board, and don't really know some of the long-standing members. I am not going to be crazy enough to brag and say that you will get the best-possible information from me, but I will say that I am not afraid to point out something that confuses me.

.

[Newell33]

I'm not worried about it, either. Just found it curious that you say you knew what it was, yet called it something else. Now that you have shared your background in auto parts, it's even MORE confusing. If it steers you away, ... oh, well.

Your profile and post count say that you have just joined recently, so you don't really have a feel for the general attitude on the board, and don't really know some of the long-standing members. I am not going to be crazy enough to brag and say that you will get the best-possible information from me, but I will say that I am not afraid to point out something that confuses me.

.

Steve,

I don't mean to be rude, but I had you pegged after your first post. The fact is there are guys like you all over message boards in every facet of the Internet. You're a wealth of knowledge, but while you excel in the knowledge department, you lack in the ability to effectively communicate with people without turning them away. You've posted three times now about something trivial. Your first post was also somewhat offensive with your use of capital letters and attitude. There are tons of guys out there that suffer from the same problem, especially in the auto parts industry. Guys with this problem don't usually survive long in customer service environments, even if they're the smartest guy in the building. Effective communication is an art. Some people are self-aware, and are able to see how their tone and attitude is portrayed to others, and some are completely oblivious. I hope you can be the former, and not the latter.

I recently joined as I'm trying to see if there's an issue with aftermarket parts. It's also good to hear other ideas and opinions, as sometimes it's nice to have another perspective on things. I appreciate everyone's responses, and I'll post what I find when I get a chance to look at the bike again.

[robertbarr]

Some people are self-aware, and are able to see how their tone and attitude is portrayed to others, and some are completely oblivious.

... and what finer example than your last post.

[Steve]

I don't mean to be rude, but I had you pegged after your first post.

Sorry, but I did not realize that you were around for my first post, nine years ago!!

And if you had been around back then, you would certainly see how well I have communicated.

Since you have me "pegged", I might just honor you with the first slot on my "ignore" list.

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[chewbacca5000]

Hey there new guy do as the GS elders suggest strip, dip, new needles and cycle orings. One additional tip is you need to make sure that the float are not getting hung up on anything including the needle jet retainer clip. I had massive overflows and this was part of the problem. I am going to strip and dip mine and rebuild with new orings.

[terrylee]

Great way to alienate yourself from one very helpful and knowledgeable long time member of this site. If you want to peg him look at all his past threads helping lots of members providing them with great advise an information and be aware he has been known to drive many miles out of his way and help others get there bikes running that might not have without help. terrylee

[Newell33]

I'm sure Steve has helped many people on this site. His first post and persistence to tell me that he knows the difference from an overflow tube to a vent tube set me off. He could have dropped it, but as you could see from his subsequent posts, it continued. Yes, I did risk alienating someone knowledgeable, but I stand by what I said. It's not a great way to start my first few posts on a new message board, but I also wasn't a fan of the tone. I've seen too many message boards overrun by very knowledgeable "Steves" that sometimes let their ego get the best of them. Sorry, but not my cup of tea.

Thanks for the help and suggestions.