Fresh carb rebuild and Engine Knocking


Information and questions on GL1100 Goldwings (1980-1983)
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4wred
Posts: 162
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Motorcycle: 82 goldwing aspencade
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Re: Fresh carb rebuild and Engine Knocking

Post by 4wred » Wed Oct 19, 2016 7:50 am



Bench testing is your friend,I learned the hard way verify the needles are seating properly without flooding before you reinstall,and I always turn the petcock off every time I shut down the engine.Too much work (pita) to keep yanking these carbs in and out.



dwight007fchr
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Location: Culpeper, Va
Motorcycle: 1983 1100 Goldwing Interstate

Re: Fresh carb rebuild and Engine Knocking

Post by dwight007fchr » Wed Oct 19, 2016 10:24 am

Update:

OK......While trying to sleep last night I had a revelation or a "what if" regarding that dern white smoke. I thought pretty strongly that it was caused by a super rich mixture on the left side. But all the floats were working (I bench tested and the gas was shutting off on all 4).

So I thought about the fuel pump.......what happens if that fuel pump is pumping at way too high a pressure to the carbs? Why doesnt it have a pressure return back to the gas tank, or some control to limit the gas pressure going to the carbs? I was thinking that if the pressure is too much, then naturally the gas is gonna push and break thru at the weakest spot inside the 4 carbs. And maybe that weak point is one or both carbs on the left side (No 2 and 4).

So I decided to bypass the fuel pump and hook up a gas line straight to the carbs as in this picture:

Fuel supply bypassing fuel pump
Fuel supply bypassing fuel pump


Bypassing fuel pump
Bypassing fuel pump

I also had a small container to catch any remaining gas that might pump out of the fuel pump...that is rigged up beside the fuel pump. I cranked her up, and there was absolutely no white smoke coming out of either exhaust. I kept adding more gas to the fuel line and had her running 10-15 minutes, and did not have all that smoking as before. Here is a pic of the exhaust pipes while running:

No smoke coming out mufflers
No smoke coming out mufflers

So my question to the experts........Have you ever seen this happen before? Seems the fuel pump is pushing gas too hard into the carbs. Any fix for this?

dwight007fchr
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Re: Fresh carb rebuild and Engine Knocking

Post by dwight007fchr » Wed Oct 19, 2016 10:25 am

4wred......You are SOOO right.....yanking those carbs in and out is a royal pain. What do you think of my idea that the fuel pump is pushing gas too hard?

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spiralout
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Re: Fresh carb rebuild and Engine Knocking

Post by spiralout » Wed Oct 19, 2016 10:43 am

dwight007fchr wrote: Seems the fuel pump is pushing gas too hard into the carbs.
Volume flow test your fuel pump. I bet it's within spec.
dwight007fchr wrote: So I thought about the fuel pump.......what happens if that fuel pump is pumping at way too high a pressure to the carbs? Why doesnt it have a pressure return back to the gas tank, or some control to limit the gas pressure going to the carbs? I was thinking that if the pressure is too much, then naturally the gas is gonna push and break thru at the weakest spot inside the 4 carbs. And maybe that weak point is one or both carbs on the left side (No 2 and 4).
Because with a properly functioning fuel pump and carbs, it doesn't need a return.
dwight007fchr wrote: Any fix for this?
Fix your carbs correctly.

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Maz
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Re: Fresh carb rebuild and Engine Knocking

Post by Maz » Wed Oct 19, 2016 1:10 pm

I'm really not sure what's going on there, but excess fuel will give you BLACK smoke and a very lumpy idle. Are you sure the fuel in the tank is good, uncontaminated gas? No Seafoam or anything else in it?
Maz
Nostalgia is not what it used to be!

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mytown
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Re: Fresh carb rebuild and Engine Knocking

Post by mytown » Wed Oct 19, 2016 4:04 pm

Fuel pump, smoke. No fuel pump, no smoke suggests fuel pump to me. Here's a couple of pics from the GL1100 manual that may help with testing it:




I'd also check what it is that activates the pump such as a cam. Here's a short video of the diaphragm in action:


The "original" 25mm float adjustment suggests to me that someone may have tried before to solve your problem and that that float adjustment was a long shot attempt at doing so. I could see trying a lot of things before suspecting the pump. In any case, no smoke is certainly encouraging.

dwight007fchr
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Re: Fresh carb rebuild and Engine Knocking

Post by dwight007fchr » Wed Oct 19, 2016 4:31 pm

Probably Final Update on carb issue:

I was thinking today that since she runs great and without any white smoke by bypassing the fuel pump, then it could have been something as simple as me using that 1/2 gallon jug of gas mounted to the foot peg instead of using the normal fuel tank. I thought that maybe the fuel pump did not have enough resistance in extracting the gas, and with that short fuel line and that jug of gas beside it (and with plenty of air coming into the jug), it was causing the fuel pump pressure to be higher than normal.

So, I went ahead and filled the tank with 5 gallons of fresh non-ethanol and my usual Marvel Super Mystery Oil, and put the correct filter and gas lines back in-line to the fuel pump. Cranked her up, and bingo..........no white smoke at all. Ran her for 10 minutes and there was absolutely none of that whitish smoke. So I am guessing that was the problem......not enough flow resistance by using that 1/2 gallon jug of gas hooked to the fuel pump.

No Runs, No Drips, No Errors
No Runs, No Drips, No Errors

So, got her all dressed up and took her for a short spin (not too far since I just took off the rear calipers and have no rear brakes yet). She sounds and runs great! I love the sportiness of this Wing without all the boxes and fairing add-ons......definately a big difference over the full dresser. Now, gotta get the brakes done so I can drive her a bit before winter sets in.

dwight007fchr
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Re: Fresh carb rebuild and Engine Knocking

Post by dwight007fchr » Wed Oct 19, 2016 4:45 pm

mytown.....Thanks for the input and the shop manual references. Yep, when you buy a 35 yr old bike, you never know what the prior owners have done to it in the past. Im just hoping that the carb/fuel pump issue and that whitish smoke is a done deal. Problem solved.....das ve dahyna/adios amigo to the smoke.

Good video of the diaphram in action.....pretty simple style of pump.

MAZ......All the testing done in the past week has been with brand new non-ethanol gas......no Seafoam or Yamalube. In my case, the white smoke was from a super rich mixture.....like No. 4 intake pipe running super cold, and then I found the gas sitting on the bottom of the air box. Maybe the color of the exhaust depends on how clean the cylinder wall is at the time of it running rich? And since this bike has been leaking gas into the cylinders for some time, the cylinder walls and rings may have had all the oil flushed off already? Not sure, but at least she seems good now.

SpiralOut.......Volumne flow testing the fuel pump was gonna be my next step if running her by the fuel tank and not the jug didnt solve the problem. Aye Coptain......I think the carbs are fixed now. If not, I will rip them out and install a high performance triple-wound Tesla Flux Capacitor and go park my Wing in front of the court house during the next thunderstorm.

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mytown
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Re: Fresh carb rebuild and Engine Knocking

Post by mytown » Thu Oct 20, 2016 1:24 pm

Can't argue with success. I was thinking all along how clean the various parts looked. Bike looks clean, sharp, sporty as you say. Wheels look great.

dwight007fchr
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Re: Fresh carb rebuild and Engine Knocking

Post by dwight007fchr » Thu Oct 20, 2016 5:23 pm

mytown....Thanks for the thumbs-up on the bike. But as they say, "you cant tell a book by its cover". Nothing seriously wrong, but its amazing how a bike can go downhill real fast when it sits around for years with no maintenance. The rear brakes are seized up, and I pulled them off today and started tearing into them......looked like a severly corroded battery terminal under the rubber boot....both the caliper pistons and the rear master pump cylinder were seized. Brake maintenance is way overlooked by owners.....and I am guilty also. On this bike, I will also tear into the front brakes after seeing how bad the rear ones are.

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RuDogGL
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Motorcycle: 1982 GL1100 Interstate GoldWing

Re: Fresh carb rebuild and Engine Knocking

Post by RuDogGL » Fri Nov 10, 2017 10:10 pm

Where is the bolt you tighten up to stop the knocking located?


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