Educate me

[3Phase]

What washer

The washer would be on one of the screws that hold the float bowl to the carburetor body. If the fuel level came up to the washer I think that's actually a little low. I scribed three marks (low limit/spec/high limit) on the carburetor bodies for my '80G and the fuel level should be a fine frog hair or two above the gasket parting line.


And I finally grok'd the 'pilot tunnel' as the hole drilled in the casting to connect the needle jets (emulsion tubes) and the pilot jet wells in the '70s and some early '80s style carburetor bodies.

[DGXSER]

Don, Columbo needs a lot more fuel than 110 or 112.5 mains can provide to waft along gently and comfortably in magic carpet mode on a hot summer day[1] in the desert but I know Steppenwolf has been running his dressed SG for decades so it can be done. I'm assuming that he's still using the stock jetting but I could be wildly and colorfully... wrong.

With all of those different carburetors you tried, what kind of time did it require for your Special to run up to red line in 5th gear and did you ride more than a few minutes or a 1/4 mile?


1. Void where prohibited by law or common sense and especially Canada or any other location where a 25C (77 in old money) summer day is routinely considered too hot to be outdoors riding a fully loaded motorcycle with the proper gear.

Scott, Steppenwolfs SG has 120 mains IIRC. Leading me to believe that for the 80 Special 120 was stock, and that they leaned them out in 81. Of course he rides pretty tame, definitely an easy cruiser rider, but he has never had any issues with lack of fuel.

As to Red line, I have never got there in 5th gear, my highest is 7,500 RPM and that was only once or twice in 5th gear. In 1st through 3rd though they have worked well up to that level. I do like to test out my low gears for slippage So far I have run two sets of 81s on it, a set of 80 carbs, and a set of 79s I believe. I honestly never paid much attention to the needle jets or the emulsions as I have never replaced either in any of my carbs to date.

Per the Clymer manual anyway, that fuel level method is supposed to use a .24" or 6 MM fuel line, and the level should be identical across th board at .12" +/- .04" or 3MM +/- .1 MM down from the seam where the bowl and carb body meet. Even an old anal retentive engineer like me has forgon that method to date though. For the 80-81 cabrs 23MM +/- .5 mm has worked great for me.

[XS1100_OEM4ME]

Thanks

I never tried to set my floats to some external part of my carb, always tried to get an exact float hight from inside the bowl, and that, if set correct should have the fuel, when carbs are level, at the gasket hight IMHO

The washer would be on one of the screws that hold the float bowl to the carburetor body. If the fuel level came up to the washer I think that's actually a little low. I scribed three marks (low limit/spec/high limit) on the carburetor bodies for my '80G and the fuel level should be a fine frog hair or two above the gasket parting line.


And I finally grok'd the 'pilot tunnel' as the hole drilled in the casting to connect the needle jets (emulsion tubes) and the pilot jet wells in the '70s and some early '80s style carburetor bodies.

[motoman]

always tried to get an exact float hight from inside the bowl, and that, if set correct should have the fuel, when carbs are level, at the gasket hight IMHO

In theory, but unfortunately doesn't work if you intend to have all four fuel levels the same. The spring loaded needles on the later carbs IMO are the cause for the bit different RUNNING float levels. I say RUNNING as that IS the correct way the later carbs should be done for exact, equal fuel levels between all four carbs. And yes, you get real good and quick pulling carbs as it will take a few removals to get all four RUNNING levels correctly the same. I belive the spring loaded needles do serve a good purpose keeping fuel levels more constant while riding, but IMHO cause variable float levels with age and heat somewhat changing fuel levels. In my scoots case having original needle/seats, seating pressures I'm sure vary along with the tiny springs in the seats collapsing at different rates. Fairly sure there are hundreds of sets of these carbs still being used with original pieces other than mine........sumptin' to consider and think about when correcting or setting float levels.

[XS1100_OEM4ME]

Cool

Nothing wrong with being that precise I am just going the easy way and so far it is working. I am not looking for max preformance or anything like that, just want her to run good there and all the way back home

always tried to get an exact float hight from inside the bowl, and that, if set correct should have the fuel, when carbs are level, at the gasket hight IMHO

In theory, but unfortunately doesn't work if you intend to have all four fuel levels the same. The spring loaded needles on the later carbs IMO are the cause for the bit different RUNNING float levels. I say RUNNING as that IS the correct way the later carbs should be done for exact, equal fuel levels between all four carbs. And yes, you get real good and quick pulling carbs as it will take a few removals to get all four RUNNING levels correctly the same. I belive the spring loaded needles do serve a good purpose keeping fuel levels more constant while riding, but IMHO cause variable float levels with age and heat somewhat changing fuel levels. In my scoots case having original needle/seats, seating pressures I'm sure vary along with the tiny springs in the seats collapsing at different rates. Fairly sure there are hundreds of sets of these carbs still being used with original pieces other than mine........sumptin' to consider and think about when correcting or setting float levels.

[3Phase]

Wouldn't you know it. I pulled one of the lowers off the fairing to look at the carburetors and I had made the marks on the float bowl, not the upper casting. Oops... What's the second thing to go after memory?

The good book of Yamaha says all the '80s Specials had 110 main jets and 5GL16 jet needles so I think Steppenwoof must have put in the 120s if that's what he's running now. It's possible that Abe the late-shift and weekend wonder chimp could have put in 120 mains at the factory but....

When I first bought and before I named Columbo, the original Standard carburetors had been swapped out and/or a full Special tuneup kit had been installed. It took a while to figure out what was wrong. The engine pulled like a freight train in 1st through 3rd and ran great around town and out on the freeway but it would start to get hot and run out of steam in 5th. After installing the correct jets and needles it basically waltzed right up to redline in 5th. Even pushing the barn door fairing the engine itself could hang in there for a lot longer than the rest of the bike and I were willing to try.

Not so much any more since the '750/'850 final drive mod. It'll still run up with no problem in 4th and cruise all day long at speed in 5th but I don't have the stones to try for redline.