So ...need a bit of direction-was carbs, not coil pick up

[JonnyO]

Jonny0, I rode an XS1B from California to North Carolina in 1974. I had 7 days to report for duty at Ft. Bragg. One of my all time best rides.
Now that I'm 70, the XS1100 will get me around in comfort without the extras the 650 added.
Every State has good and bad parts to it. On a ride, we try to stick with the good parts or roads. Cal. has highway 1 North of San Francisco, Arkansas has their highway 9, and so many more!

Gave me a smile to read of your trip to Ft. Bragg.
My first bike was an XS400 I bought while in the Navy. When we were stateside I was one of the few with a motorcycle onboard. I'd hit ports on the Left Coast ( it wasn't at the time ), offload it and ride to wherever the heck I wanted. lmao
Wish I knew then what I know now.

[JonnyO]

That translates to a JIS (Japan Industry Standard) S8 o-ring, meaning it's a common standardized size (JIS S8) Many auto parts stores keep assortments of single orings behind the counter, they're all over the place in systems that use fuel injection and are labeled by they're standardized size.

Long and short of it, head to an auto parts store and ask if they have single orings and ask for a JIS S8 o-ring, probably won't cost more than some pocket change.

Good suggestion but that's for you more competent mechanics to do. I've not the courage to take a chance that what I found might be up to snuff. I'm getting OEM. lol I bite the bullet and cough up stupid money on certain things because
in my experience I always get the shaft. My best friend Sal used to say, " If the turtle doesn't stick his neck out of the shell he never goes anywhere." And after he tried whatever it was ( installing floors ) and it turned out it was a mistake I'd say, "Oops ...and get's it chopped off!".

[LAB3]

My experience comes from the necessity of figuring things out while out on the road. Right now I'm a good 30 miles from anything remotely resembling a motorcycle shop let alone a Yamaha dealer. If my carbs spring a leak I've got to find parts that work, having options in finding them is crucial!

[JonnyO]

My experience comes from the necessity of figuring things out while out on the road. Right now I'm a good 30 miles from anything remotely resembling a motorcycle shop let alone a Yamaha dealer. If my carbs spring a leak I've got to find parts that work, having options in finding them is crucial!

Yeah, I hear ya. Self-reliance. Not too bad for a family of four! nyuk nyuk!

[JonnyO]

YAY! Found two things-one, the rubber gasket I couldn't account for after spilling out all the screws and fasteners of the air box ( was laying on a rug behind the bike ) and two, a PICTURE of where I suspected it should go- under the brackets held in by the two philips head screws. For me, a major victory!

[bikerphil]

Hey Jonny, you can reuse the needle seats if you polish them. Cut a Q-tip in half, put it in your drill, apply chrome polish and buff the inside where the needle sits. Also clean any deposits off the needle itself and visually inspect. New ones aren't cheap (the good ones), but the o-rings are.

[Appie]

Yay! \(^_^)/

FWIW? (*′☉.̫☉)

Iffin yur feeling a bit reluctant to do a total tear down, clean, rebuild, adjust, install, and RE-adjust a set 4 (fower...) Mikuni BS-34 Constant Velcity CaburatatorZ??! ヾ(ﾟдﾟ)ﾉ゛

Then imma gonna say there's prob'ly a good reason on yur side of thingz. (／。＼)

I means, ya don't R E A L L Y knows what yur in fOaR and wut to expect OaR DO as it's a "first time thru the Gate" scenario. Iffin that's the case then I heartily recommend you DON'T. Just DON'T. ε=┌(;･_･)┘

There's only so many of these carb banks left and nobody wants to see the bank (and therefore the entire bike...) useless cuz of ruining one....just ONE carb body due to being HAMHANDED 'bout removing a float post, jamming the wrong size screwdriver into the pilot air jet hole and cracking the horn, OaR boogering up the idle fuel screw tip/hole. (－‸ ლ)

I would totally support you taking NO action at all considering at this moment yur deciding NOT to do anything cuz you KNOW that you DON'T know wut you NEED to know. (︶︹︺)

BefOaR making a final decision to act OaR not to act? (O_o)

You might find the following useful-

https://xs11.club/forum/repairs/carb...b-cleaning-101

https://xs11.club/forum/repairs/carb...-1980-81-carbs

This video channel has the mostest detailed and useful videos in this area that I've EVER seen and I've used them as my own guiding light.-

https://www.youtube.com/@Steptoexs11/videos

Know befOaR you go.... ( ﾟ_ゝ｀)


OaR DON'T go if that ends up being the case. ¯\_(°_°)_/¯

Yoh Larrym I watched one of steptoexs11’s videos last night. That guy really knows what he’s doing! Essential watching for a beginner like me, how is it that his videos aren’t watched more often? Anyway, thanks for the link and this thread JohnnO and others, I haven’t yet read something here that hasn’t changed my way of thinking and approaching these bikes I agree, they really are too valuable to damage by jumping into a repair without having the correct knowledge. 👍

[JonnyO]

I only use the genuine Yamaha on those seat O-rings, P/N 8F2-14147

Soak the hell out of those seats with penetrating oil before trying to pull them out. I've even needed to heat them with a torch to remove them before. Be careful of the float posts.

So I've got Blaster and those seals ( Partzilla ) on the way...
"Hey Jonny, you can reuse the needle seats if you polish them. Cut a Q-tip in half, put it in your drill, apply chrome polish and buff the inside where the needle sits. Also clean any deposits off the needle itself and visually inspect. New ones aren't cheap (the good ones), but the o-rings are."
Is there a specific video tutorial on replacing those anywhere online...and polishing the seats? Just asking so I can get my box of Crayolas handy.
I have a dremel and a bunch of polishing bits-

[cajun31]

I use this kit from Harbor Freight. Engine Brush Kit, 20-Piece. The brushes fit a drill if you want to be that aggressive but just using the hand tool works fine. I like the kit because you have vinyl, brass and steel brushes to choose from. You don't want to get too aggressive; your goal is to simply get any deposits or grooves smoothed out so that the needle slides smoothly up and down in the seat. One other thing, you have a special so your needles have the rubber base on them and you need to verify that it is still pliable. If not they need to be replaced. The also have a small brass needle on the tops of them and those need to move up and down freely. if they don't then again they need to be replaced. I have has some success with soaking the needles in the gallon can version of Berryman's and they sometimes loosen back up. The problem with all of these small parts is that evil ethanol in our gas these days.

[Larrym]

The also have a small brass needle on the tops of them and those need to move up and down freely. if they don't then again they need to be replaced.

That little needle/post thingy ends up bein' W A Y mOaR impo'unt than you'd expect. ( •_•)

Somehows, there's a teency-weency SPRING inside the float "needle" thingy which determines just how much that needle moves in/out of the needle body whens the pointy end is s'posedly bottomed out against the SEAT (and s'posedly stopping the flow of fuel...) and the weight of the float is supported by that needle/spring thingy whens you gots the carb upside down and are trying to set the float height to the standard/special float height/distance. (⊙▂⊙)

In the Flea-Bay kits all the needles lookey the same on the outside BUT when you's setting the float levels across all four carbs? (O_o)

Same float weight (relatively...) ends up encountering WAY different spring strengths (QC issue?) so's the actual float height(s) (cuz they're bein held up BY those teency springz....) ends up bein all OVER the place. (－‸ ლ)

So's you end up adjusting the float levels to the same height(s) cross the bank thimkin you done the right thing. (^_^)

But you DIN'T and the bike will TELL you so. (_Oo)

The OEM springs are S T R O N G so's when ya flip/bounce the floats wit yur finners? (O_o)

They bounce back nice-n-firm to the same height. (^_^)

(A N D they's all mOaR or less the same level of strong cross all four of'em...)

[motoman]

JonnyO, pertaining to the carbs and floats, with float bowls removed lay the gaskets in place on each of the bowls. If gasket has any slight overhang towards inside of bowl it can easily cause float to hang up. With gasket in place on float bowl, take a razer blade and follow against inside edge of float while slicing off any excess gasket.

[LAB3]

JonnyO, pertaining to the carbs and floats, with float bowls removed lay the gaskets in place on each of the bowls. If gasket has any slight overhang towards inside of bowl it can easily cause float to hang up. With gasket in place on float bowl, take a razer blade and follow against inside edge of float while slicing off any excess gasket.

Yep, that one seems to be an issue on mikuni carbs in general not just the one's for the XS

[Schming]

That little needle/post thingy ends up bein' W A Y mOaR impo'unt than you'd expect. ( •_•)

Somehows, there's a teency-weency SPRING inside the float "needle" thingy which determines just how much that needle moves in/out of the needle body whens the pointy end is s'posedly bottomed out against the SEAT (and s'posedly stopping the flow of fuel...) and the weight of the float is supported by that needle/spring thingy whens you gots the carb upside down and are trying to set the float height to the standard/special float height/distance. (⊙▂⊙)

In the Flea-Bay kits all the needles lookey the same on the outside BUT when you's setting the float levels across all four carbs? (O_o)

Same float weight (relatively...) ends up encountering WAY different spring strengths (QC issue?) so's the actual float height(s) (cuz they're bein held up BY those teency springz....) ends up bein all OVER the place. (－‸ ლ)

So's you end up adjusting the float levels to the same height(s) cross the bank thimkin you done the right thing. (^_^)

But you DIN'T and the bike will TELL you so. (_Oo)

The OEM springs are S T R O N G so's when ya flip/bounce the floats wit yur finners? (O_o)

They bounce back nice-n-firm to the same height. (^_^)

(A N D they's all mOaR or less the same level of strong cross all four of'em...)

And ^^^^^THIS^^^^^ is why the fuel levels static and running should be checked to get optimum performance.

[Radioguylogs]

I tried static and the results were erratic:




I tried running, and the results were accurate.

[DiverRay]

Without the vibration from a running engine, air bubbles in the "gas" can cause problems. I say "gas", because I CAN get ethanol free gas in Idaho, and it makes a BIG difference on the way the bike runs.