weak float valve springs?

[bikerphil]

Looks like in that pic that he is measuring with the gasket installed. It'll probably run like that tho.

[EricHa]

Yes that pic is with the gasket. I should have taken the shot without it. They are close to 1" without and 3mm higher than before adjusting. They're back in the bike so I'll test them out, but will be more precise when I pull them back out.

[EricHa]

ok. I finally got to work on the bike for a few hours, and am still having issues. The carbs were still rich after the last float adjustment, so I pulled them and raised the floats even further, to 27mm. I also bought a Colortune as I need all the help I can get. When adjusting the idle screws, the mixture shows quite rich until each screw is around 3/4 turn out. I don't get anything like bunsen blue until the screw is closed. Also, the idle doesn't drop when the screw is closed. On the other end, the idle drops when the screws hit about 2 turns out.

So I had the screws around 3/4 out and did a 3 minute test ride. It ran weak, and of course had no top end power. Where do I go from here? What could be the problem? The pilot towers have the screws on them. The bike seems rich on the bottom, and lean on the top. I must admit that I'm getting really frustrated on this deal.

One more question, do I use the Colortune at idle, or partial throttle? I've been using it at 1200rpm.

[EricHa]

I remembered this as well, but timed out on editing. The last thing I can think of, is I had someone else rebuild these, and haven't actually checked the needle clip. Could this be causing this problem if it isn't in the middle notch? I will definitely check it the next time the carbs come off.

[bikerphil]

Yes, use the colortune at idle. Yes, check the location of the needle clips, put them in center position. JAT, the wrong type of pilot jets will give you a constant rich condition, they should have 6 air bleed holes in the side.

[EricHa]

Hey that's right, I need the "96" ones, or whatever they are called. The guy may have indeed put the newer pilots in. I'll check them tonight. Thanks for the tip Phil. I really appreciate it!

[motoman]

Hey that's right, I need the "96" ones, or whatever they are called. The guy may have indeed put the newer pilots in. I'll check them tonight. Thanks for the tip Phil. I really appreciate it!

That's BS30/96. Just some advice: replace those float needles with new or you'll chase your tail forever. The little springs not reacting the same to load WILL leave you with float levels all over the board. I can 'hose' the levels on 81 carbs while it's running, and IS the reccomended procedure for 81 and later 34series Mikunis. Having seen the varying levels when staticly, the floats are set identical(within .001) proved that the seats need just a bit more load to seat and seal. Having the spring loaded needles allows the float to come up a bit more creating more pressure on the seat and sealing. Result is a higher fuel level. Replace the needles.....it will magicly result in a normal running bike......instantly.

[EricHa]

Thanks Moto, I will do exactly that. Any idea which float needles I need, in regards to part number? I would start searching through here, but I have an order from Mike's that I would like to add these to if I have time. Their shipping is HIGH. My downloaded service manual doesn't show the part #.

[EricHa]

ok, I think I found them on MikesXS. Part #48-5019 for 78-79 XS1100. I will get these replaced as well. Thanks again for the tip. I wondered if those weak/inconsistent springs were a bad deal.

Besides a great ultrasonic cleaning job, I should have rebuilt these myself. Lesson learned.

[EricHa]

I pulled the carbs this weekend, and Phil's insight on the pilot jets was spot on! 8 hole pilots had been installed. I had ordered BS30/96's last week after his input, so the correct pilots are now installed. Needle clips are set in the middle, so I should be good there.

As to the pilot valves, I'm still waiting on new units from Mikes, but tried Tom and others tip of slanted cutters/pliers on the float pins. The heads were really flush to the posts, so I cautiously set to looking at the open end. Turns out that all are loose in the posts, and come right out. Yes!

As for main jetting, I have 140s and 142.5s on the way, along with the stock 137.5s. With a 4 into 1 and airbox with K&N element, which may prove to be the best set to try first? The bike hasn't pulled hard on top since I had the stock filter and rusted out OEM exhaust installed.

[bikerphil]

Hope this fixes it for you, I've been down that road before with wrong pilot jets. The spray angle in those VM's is NG.

The older carbs don't seem to be that picky on main jet size as the newer type carbs.

Size depends if you want more power or better fuel mileage.

[EricHa]

Hope this fixes it for you, I've been down that road before with wrong pilot jets. The spray angle in those VM's is NG.

The older carbs don't seem to be that picky on main jet size as the newer type carbs.

Size depends if you want more power or better fuel mileage.

Thanks for your help Phil. Those pilots were making me doubt my ability to tune one of these old beasts, but I'm learning a bunch, especially to be patient and probably be more methodical. I'll try the 142.5 mains as performance trumps mileage at this point.

I have the fairly conservative Jardine baffle for the header, as well as a Vance Hines competition baffle that I've made to fit. I imagine that the Jardine will give me better midrange grunt, which is what these Elevens are known for, and what I want. Maybe that will mean the 140 mains, or 137.5s. In any event, I'm getting good at pulling carbs.

[bikerphil]

142.5's should be fine with 4-1, K&N/airbox. You can run either 42.5 or 45 pilot with no problems.

I run 4-1 Kerker, K&N/drilled/chopped airbox 45/145 with no issues, still get about 38 mpg.

[WMarshy]

142.5's should be fine with 4-1, K&N/airbox. You can run either 42.5 or 45 pilot with no problems.

I run 4-1 Kerker, K&N/drilled/chopped airbox 45/145 with no issues, still get about 38 mpg.

Eric,

I suggest the 45's and 140 or 142.5 with your setup... I had the same setup you currently have, at one point, with 42.5/137.5 and it was lean down low in cold weather and fell a little short at WOT. I imagine the 140-142.5's would be right. If you drill your air box and put that less restrictive baffle on then the 145's would sing. Let us know how it works!

[EricHa]

Eric,

I suggest the 45's and 140 or 142.5 with your setup... I had the same setup you currently have, at one point, with 42.5/137.5 and it was lean down low in cold weather and fell a little short at WOT. I imagine the 140-142.5's would be right. If you drill your air box and put that less restrictive baffle on then the 145's would sing. Let us know how it works!

Well, I do have another old airbox laying around, and it just so happens that I have a drill as well. I'll try your suggestion on the 45's too, as I'm really excited to get this thing tuned just right. WIll update the saga as it unfolds.