Question about float level

Hope someone here can answer this question. My 77 1000LTD has 26mm Mikuni's that have a thin wall around the bottom of the carbs that the bowls fit up into. This wall sticks down about 3mm from the gasket surface. So when I measure the float height with a clear tube should I measure 3mm down from this wall or even with this wall because it is already 3mm down from the gasket surface? Hope this makes sense.

All the illustrations I see show you measuring down from the base of the carb but what I read says to measure down from the gasket surface. On my carbs the gasket surface is about 3mm above what you can see when you look at the carbs with the bowls attached..

Thanks

Take your bowl off and hold it level. You should be able to see the overflow tube sticking up ever so slightly above the rim. You want to set your fuel level below that tube. So it's 3mm below the gasket surface on the carb. That is where I set mine on the 26mm's. Someone correct me if i am wrong. They don't overflow.

Thanks for the reply. Reason I asked the question is my floats were originally set by measuring the float height since I didn't have a tube that would fit in the drain holes. I really didn't know how high the level actually was but the bike has run well for several years this way. I just started to leak some gas from a couple of the overflows and tapping the bowls didn't fix it. The needles are 8 years old so I replaced them and bought a float adjusting tube tool. The new needles looked identical to the old ones so I figured I should be close to the right height. When I checked with the tube it appeared my floats were all too high if you go by the illustration where you set them 3mm down from the base of the carb. So I readjusted them by bending the tang on the float until they were 3 to 4mm down from the base. Unfortunately the bike misses badly and won't idle without some choke. It acts like it is starved for gas. I'm going to put the height back to 3mm below the gasket base and see if it fixes the problem. Thanks again!

It seems like you've already gotten your answer, but the gasket surface stuff is probably in regards to doing them dry. To do the service fuel level check (wet) the manual probably says to take the measurement from the bottom of the carb body - there's probably a drawing & it's probably the most suitable reference point for measurement.

I do have a manual and it does say to measure from the bottom of the carb body. I just seem to remember reading that you should measure from the gasket surface. Anyway I changed the float level to be 3mm from the gasket surface and the bike runs good now just like before. Possibly the float level should be lower and the bike likes the higher level because it was jetted that way. I used to think that as long as the jets were all submerged the float level didn't really matter too much but now I've seen for myself how much of a difference a small change in float level makes in performance. I think I raised the level about 5mm from where it was before and it made a difference from a bike that wouldn't idle without the choke and felt like it was running on 2 cylinders to one that idles at 1100rpm and runs great. I'm still learning things after having this bike for 36 years. Thanks for the reply.

First off...that is a very sweet bike :woohoo:
How long did your bike sit without running? When you say you rebuilt the carbs did you really clean all the passages especially in the idle circuits? Patton had posted a few times with good drawings and directions on how to do this...very informative. If your bike say for a while the carbs could have some gumming up. Another thing to check is the advancer that sits behind the points cover, make sure that is not sticking.

Thanks, it has 40k and still has the original paint, although I have painted the frame several times. I put the sissy bar on so my wife would feel more secure but I think the bike looks better without it. The bike had sat since the end of riding season last fall. It took longer to get in going this year because of work and I had the discs resurfaced and drilled plus replaced the rear tire. I always drain all the gas because I store it in my basement. I did see the drawing from Patton where you spray carb cleaner in 1 and block 2 and it should exit at 3. I went thru this when I had the carbs off to change the float needles. It seems to be running good now that I have the float levels set.

Wow...

I love this forum. I am just surfing, see this topic.

I have the exact same issue and suspect float level. Motivated now.

What a beautiful survivor, from what I understand now as rare as hen's teeth!
I am very interested in what you did with your brake discs as mine (I too have a 77 B1) despite being doubles are just not performing well. Did you have shop do this or did you do it yourself? I like the pattern of holes you have better than the ones on later bikes which are more vertical and not symmetrical.

Thanks, I've tried to keep it looking original. I sent the rotors to TruDisk in Michigan. Tom charges $45 per rotor to resurface and $25 per rotor to have them drilled. He does NOT charge per hole! I tried to go easy on him and suggested a pattern that repeated 6 times but he said it would look better with a pattern that repeated 12 times so I said "drill away". He puts a nice crosshatch pattern in them. I'm still seating the pads but they already stop a lot better. The rotors were so glazed over before that I would have to clean them with brake cleaner a lot to try and get the brakes to stop better and keep them from squealing.

www.truedisk.net/

this post just solved my horrible idle problem and i 2 would have to choke it just to keep it running. and i did just replace one of the floats. so it must not be adjusted right

Hope you get her fixed.