Carburetor Bench Test results and questions


Information and questions on GL1100 Goldwings (1980-1983)
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shevik
Posts: 51
Joined: Sat Sep 28, 2019 2:08 am
Location: Phoenix, Az
Motorcycle: 1982 GL1100i

Carburetor Bench Test results and questions

Post by shevik »



1982 GL1100

Hey everyone, I'm back at it again with my carbs. So I put them back on the bike after my last round of maintainance and it ran great for a while until it started puking fuel out of the exhaust..

So they're off again and I'm double checking my work. I'm pretty sure I know which carb is the culprit because cylinder 2 was luke warm to the touch even though the others were hot.

I was very precise with my float heights so I don't think that's the issue, but I'm still pretty sure it must be the float in that bowl.

So I hit with an air compressor and it so far checks out, right side up air passes through each valve like it should, upside down air doesn't get past the float valves.

I still need to try it with gasoline instead of air. If my thinking is correct then the problem float isn't reseating like it should and gasoline is flowing freely through that float valve, flooding the cylinder, and draining into the exhaust pipe.

I still need to soak the floats in gasoline to see if the problem one sinks and weigh them to be sure.

In the meantime I have one silly question and also want to petition for general advice.

I'm uploading a picture of my float needle. Can someone tell if it's original and which way the tines are supposed to face when it's seated? I couldn't find am answer. :geek:

Edit, one other clue: when I took the bowls off the problem one had less gasoline in it than the others.

Edit: When I really crank the PSI up on the compressor the problem float bow moves significantly more than the others indicating a weaker seal!

Edit 2: Ok when I crank the pressure up they all behave erratically so maybe not a useful line of inquiry.
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Float needle
Float needle



If I just work hard enough I should be able to get her out and about before riding season is over.
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Rambozo
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Motorcycle: 1992 GL1500 Aspencade

Re: Carburetor Bench Test results and questions

Post by Rambozo »

Tip looks trashed. I would replace that Needle.
You only want to blow with a couple of psi. I use my mouth not a compressor. More feel that way.
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Maz
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Motorcycle: 1975 GL1000K1
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Re: Carburetor Bench Test results and questions

Post by Maz »

+1 on what Rambozo said. The "tines" are only there to centralise the needle in the jet, whilst allowing fuel to flow past, so it can fit in any orientation, as long as the wire is hooked over the operating tang.

Maz
Ironically, Common Sense is the LEAST common of all senses!
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2003Cobra
Posts: 129
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Motorcycle: 2003 Goldwing GL1800 with a CSC Cobra trike kit.
1988 Harley Davidson Sportster
1985 Honda Saber VF1100 (Non-runner)

Re: Carburetor Bench Test results and questions

Post by 2003Cobra »

In addition to Maz and Rambozo post's, Check the needle seat for any trash, nicks, scratches etc.

I also agree with Rambozo the needle tip looks like it has seen a better day. Personally if I'm replacing one I'll replace all of them because if one has gone the rest are sure to follow.
2003 Goldwing GL1800 with CSC Cobra trike kit.
1988 Harley Davidson Sportster 883 with Hypercharger Bobber.
West GA Chapter 89 Southern Cruisers riding club.
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ride dont hide
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Motorcycle: 83 GL 1100 80 CB 750K 68 BSA Royal Star 69 BSA Firebird 69 Triumph Chopper 60 BMW R26 and more.

Re: Carburetor Bench Test results and questions

Post by ride dont hide »

My two cents worth: Make sure the plunger on the wire clip end is not stuck. It should move in and out freely when depressed with your thumbnail. Been there- leaked that.
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shevik
Posts: 51
Joined: Sat Sep 28, 2019 2:08 am
Location: Phoenix, Az
Motorcycle: 1982 GL1100i

Re: Carburetor Bench Test results and questions

Post by shevik »

Update:

Hey everyone!

I'm happy to say the carburetor work is done!

Turns out I had completely misadjusted the float levels. I was adjusting them from the position of a level plenum. I still can't remember where I got it in my head to do that instead of tilting it back until the float tang was resting on the spring in the valve but not depressing it. I never needed new float valves to begin with but I bought them and put them in anyways before I realized I had a float problem. Always read directions slowly and carefully!


Also, anytime you do carb work remember to put the pins back in the intake boots before trying to start it up. I didn't realize I had forgotten until little jets of flame started to spit out of the boots after an hour of me and a buddy scratching our heads. It was kind of sick, we lit a ciggy off of it before we fixed it.


Anyways now that the carb is working the bike holds idle pretty well! Still needs a proper sync, but low and behold the fuel pump gave out after about 5m of idling. Gas started to spray a little out of the weep hole pretty quickly. Luckily a new pump is relatively inexpensive and they're pretty much plug and play as far as I can tell so I'm not too worried about it.

Gives me a good excuse to stay off the bike until I can afford insurance after I'm done buying christmas presents for everyone.

So I'll now be turning my attention to the sites many threads about fuel pumps and then probably to air shock rebuilds. I couldn't be more stoked.

Hearing her pur last night after having it pickled in my backyard for nearly three months made the whole odyssey worth it. Not to mention how much I had to learn about wings!

Much indebted to the community here,
Dillon Wild


If I just work hard enough I should be able to get her out and about before riding season is over.
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