'80 GS 550 L -- Carb Tuning Question

[Guest]

Hi All,

It has been some time since I've been on the forum. I had completely rebuilt my bike a few years ago adding a K&N box Air Filter and a Mac 4 into 1 pipe.

I've ordered a stage 2 Sigma6 racing jet kit as the bike was having lots of running problems (eventually it just wouldn't start, and so it has sat for some years). I would have preferred a Dyno kit as they provide the exact parts required, while the Sigma6 kit gives you a general range.

With the enhanced airflow that I noted above, does anyone have experience to comment on if this combination sounds accurate:

Carbs [NODE="1"]Home[/NODE] + [NODE="4"]Groups[/NODE] = Main Jets 97.5 or 100?
Carbs [NODE="2"]Forum[/NODE] + [NODE="3"]Blogs[/NODE] = Main Jets 100 or 102.5?
Mixture Screws = 3.5 turns out?

Thank you,
Drew

 

[Guest]

That should read:

Carbs 1 & 4 = Main Jets 97.5 or 100?
Carbs 2 & 3 - Main Jets 100 or 102.5?

 

[Rich82GS750TZ]

Sorry, no recommendations for a fix on the carbs from me.

It is possible to edit a post for clarity, then delete your second one.

The number sign thing got you. For what it's worth:

This is a real oddity that I’ve not seen on any other forum. It showed up after the site upgrade a few months ago. I’m sure, among all that Frank administrator does here, this is not a priority, I was just curious, is all. Folks keep asking about it.
Have we figured out why this happen or how to fix this? There are probably more than 30. That’s just as far as I went to illustrate the point.

when we use a hashtag followed by a numeral: (first set I added a space between the # and the numeral)
# 1
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# 6
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# 16
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# 20
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this set with no space:
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Ladies Only​

 

[Nessism]

How are the valve clearances? Tight valves can keep a bike from starting, not to mention, it will result in burned valves and valve seats.

 

[Guest]

Thank you for the heads up on the "#" situation

Regarding the valves, they were lapped and shimmed during the rebuild stage. Cylinders were honed and rings replaced. The carbs I had cleaned and rebuilt by a shop. New OEM intake boots and intake boot orings. The idling was always a problem, either too high or too low.. surging etc. It ran terrific in both low, mid, and high range! It was always just the idling and starting that was an issue. Became harder and harder to start, ended up using starter fluid, and then eventually even that wouldn't work

 

[Rob S.]

You don't say why you didn't get the Dynojet kit. (It worked beautifully on my 11E after I added pods.)

 

[Guest]

You don't say why you didn't get the Dynojet kit. (It worked beautifully on my 11E after I added pods.)

I emailed Dynojet and they did not have the kit for 1980 GS 550 L. I wish they had it after hearing everyone’s success with them

 

[Nessism]

Dynojet has a kit for the 550M, which has the same engine and carbs. That will work.

 

[rphillips]

If it won't start with starting fluid, would that lean towards maybe a non carb problem? heck ought to run on starting fluid without carbs.

 

[Guest]

Dynojet has a kit for the 550M, which has the same engine and carbs. That will work.

what year is the 550M? I am not familiar with that bike. If it is the 1981 550M, I’m reading that it has 34mm Mikunis. My 1980 550L uses 32mm Mikunis — would that be an issue?

 

[Guest]

If it won't start with starting fluid, would that lean towards maybe a non carb problem? heck ought to run on starting fluid without carbs.

To be fair, I never tried spraying starter fluid directly into the cylinders with the carbs off because I was afraid I’d damage them

 

[rphillips]

Point meant to be, no matter how you use starting fluid, thru the filter, remove filter and thru the air box, remove air box and straight into the carbs, remove carbs and straight into intakes, it should run on the fluid unless another problem.... I'm no expert, but just seems if won't run on fluid, may not be a carb problem.

 

[Guest]

Thanks I appreciate the feedback. Will give an update once I’ve cleaned up carbs