Float Bowl is Eating Needle Jets

[System9]

I'm starting a new thread with this specific issue, but the discovery of it can be traced to an earlier problem I had (and still ongoing) relating to mysterious fuel leaks. Here is that thread if you want to know some back story http://www.thegsresources.com/_forum/showthread.php?t=189495&highlight=leaks+kickstand
I was under the impression that my needle jet may have been put in backwards, I posted a photo and was told that it was definitely wrong. Well something is wrong, but its not because its in backwards. The difference between my carbs, and those from the GS450 rebuild guide, is that when I remove my float bowl, the needle jet stays inside of the float bowl, not the carb body. Heres a picture

My old needle jets were so firmly stuck into the float bowl, that I damaged them trying to remove them. Well my new needle jets arrived, i put on fresh o-rings, and they went right into the carb body the way they are described as doing so by the carb guide. Heres the big weird problem. When i go to put on the float bowl, it wont! It seems the needle jet doesnt want to go into the float bowl. Now, I got it to go in by tapping it with a screw driver handle, but then it becomes stuck in the float bowl, and i'm right back where i was to begin with, scratching my head and wondering if its supposed to be that tight, and wondering why in hell the needle jets in the carb guide are sticking into the carb body, and not the float bowl.
Well, i put it together and put the carbs in my bike. This is after a carb dip and all new o-rings. The bike takes forever to start, and when it finally does it runs bad, maybe on 1 cylinder, and fuel is leaking out. So I'm 1 step forward and 2 back.
But, as a backup plan I had ordered a complete set of old gs450 carbs off of ebay. I decided to remove the float bowl to see how tightly the needle jet was seated into the float bowl. Now, these ebay carbs are in rough shape, so I didn't know what to expect when i popped them open. To my surprise, the float bowl came right off, and the needle jet was securely planted into the carb body, and not at all into the float bowl.
So, which way is it supposed to be? I'm assuming the needle jet is supposed to only get stuck into the carb body and never the float bowl. But then why in the heck is my float bowl eating needle jets? Its the same in both of my float bowls, needle jets slide in fine until the last 1/4 inch of the float bowl. Its like the tube becomes too small all of a sudden.
Any Ideas or theories?

 

[chuck hahn]

Did you very THOROUGHLY clean the bowl and down in the hole it fits in? Like with a brass gun cleaning brush or something to that effect to get any scale and corrosion out???

 

[System9]

Visually, they look very clean. They have been carb dipped, cleaned multiple times and air blasted. There is definitely no corrosion in there,
but it seems like there may be something else there? Like a small spacer or something? I'm not talking about the main jet obstructing from the opposite side either. Is the diameter of the float bowl tube that the needle jet sits in supposed to maintain a constant diameter throughout? Both my float bowls behave Exactly the same, in that it seems there is something in the end pinching the needle jets. If this is wrong I may have to drill it out because there may be some other piece in there?

 

[AJ]

From your pics, it looks like you have that white corrosion that is so common since they started using alcohol in the gasoline. It's a real problem with carbs built earlier than about 2001, and (in my experience) carb cleaner /carb dip does not remove this stuff.

Consider taking a twist drill bit and carefully ream the hole by hand (not using a power tool of any kind!).

Use number drills like machinists use (not the "standard" set for homeowners). If you don't already have those, you want something like this: http://www.amazon.com/Bosch-BL0060-..._9?s=industrial&ie=UTF8&qid=1333109594&sr=1-9
Fit the shank end of the drill bit into the hole by hand to determine the proper size. Then spray some light machine oil or a few drops of Marvel Mystery Oil and gently ream the hole out. It won't take much force at all to remove. Should be very easy to fix.

While you're at it, suggest buying a set of the miniature number drills numbers 61 to 80, together with a pin vise. Something like this: http://www.amazon.com/Mini-Drill-To...PRNQ/ref=sr_1_3?ie=UTF8&qid=1333110754&sr=8-3
These are very useful to clear your pilot jets. That white corrosion is very hard to clean out, and often breaks free, magically migrating to clog your pilot jets.

 

[AJ]

Ok, did some research for you. Here's a pic of the 1982 GS450T carb. I don't see anything underneath that needle jet, just the tube that keeps pulling out and the main jet.

Also, there must be some kind of port from the open part of the float bowl into the hole the needle jet tube slides into. Verify that is clear so gas can get to the main jet.

 

[System9]

I am currently soaking my recently obtained ebay floatbowl in carb dip. Tonight I will clean that one up and then compare it to the one that jams the needle jets. If I get home in time to use good sunlight, maybe I can see whats going on. I just hope my new needle jets aren't damaged from being squeezed so hard.

 

[System9]

I took the float bowl off of the carbs I got from ebay and did a comparison. Here is a video of that.
http://youtu.be/ocdSjmHOIFo

The jets go right into the other float bowls with no effort at all. I can't figure out why my originals are blocking the jets. At this point i'm thinking I will just have to drill it out if I want to use my original float bowls.

 

[chuck hahn]

Roll up some emery cloth and twist that around first and sand the bores a bit before resorting to drills. Least invasive first, then ramp up if needed is the rule of thumb I use on things like this.

 

[chuck hahn]

Also just out of curiosity...can you feel any burrs on the OD of the tubes?? Maybe some 1000 wet dry sand paper to lightly do a deburring of them as well.

 

[GateKeeper]

just wondering, if you poke the needle jet from the other side, will it go in and how far in will it go ? poking the needle jet from the bottom of the bowl, the long end, not the end where the O ring is.

in your video it's as though the bottom of the passage tappers to a smaller diameter, and not allowing the needle jet to go all the way

 

[System9]

Also just out of curiosity...can you feel any burrs on the OD of the tubes?? Maybe some 1000 wet dry sand paper to lightly do a deburring of them as well.

The needle jet tubes do not have burrs. In fact, the end of the needle jet, the part that gets stuck is so shiny smooth that it looks polished, because its being forced into a hole with absolutely no space around it. I'll attach a picture of my old needle jet.

Its as if the entire bore of the last 1/4 inch of the float bowl chamber is way too small.

 

[BigD_83]

Just my opinion, but having watched the video, the float bowls that came off your bike look shoddy in comparison to the EBay version...like a knockoff. The centre column in the float bowl looks shorter too, in comparison to your EBay version, but that could be lighting/angle effect

 

[System9]

Just my opinion, but having watched the video, the float bowls that came off your bike look shoddy in comparison to the EBay version...like a knockoff. The centre column in the float bowl looks shorter too, in comparison to your EBay version, but that could be lighting/angle effect

They are exactly the same height, but there are a bunch of subtle differences in the casting, it really has me wondering where my original float bowls came from. The e-bay float bowls are stamped with a Japanese character "タ? My originals do not have any Japanese text on them.

 

[AJ]

The needle jet is obviously supposed to be located by the metal ring at the top and there should be no interference from the receiver tube in the float bowl. (Duh!) So what's stopping you from just trying the new float bowls on the old carbs? Guessing that you need a new needle jet after destroying your old one? I feel your pain.

 

[System9]

The needle jet is obviously supposed to be located by the metal ring at the top and there should be no interference from the receiver tube in the float bowl. (Duh!) So what's stopping you from just trying the new float bowls on the old carbs? Guessing that you need a new needle jet after destroying your old one? I feel your pain.

I did just that today, I had to wait while the ebay float bowls soaked in carb dip for awhile. I even used the old needle jets from those ebay carbs ( my new ones died a horrible death on removal) They worked great. I even found out that my original float was not shaped correctly, I also swapped that with the ebay float and that fixed my mysterious gas leak while the bike was on its kickstand! So now, I fear that because my old float was messed up, that gas may have leaked into the engine, so I need to do an oil change. But overall i'm super happy I bought those old carbs off ebay, because every part I've used from those has been a success. They look like sh*t, but I'm going to try and clean them entirely, and put the whole set on the bike just to see the difference.
Thanks everyone for advise.

 

[AJ]

I did just that today, I had to wait while the ebay float bowls soaked in carb dip for awhile. I even used the old needle jets from those ebay carbs ( my new ones died a horrible death on removal) They worked great. I even found out that my original float was not shaped correctly, I also swapped that with the ebay float and that fixed my mysterious gas leak while the bike was on its kickstand! So now, I fear that because my old float was messed up, that gas may have leaked into the engine, so I need to do an oil change. But overall i'm super happy I bought those old carbs off ebay, because every part I've used from those has been a success. They look like sh*t, but I'm going to try and clean them entirely, and put the whole set on the bike just to see the difference.
Thanks everyone for advise.

Congratulations! Good work.