79 standard carb question

[bigb9582]

ive been searching for a while a could find a good answer so i figured i just go ahead and ask.
i think i need float valves for my 79f and would like to know what size they are so i could maybe see if any local yami. shops have them cheap.
or if any from mikesxs would fit. they seem to be the cheapest place online. Part #48-5019 and Part #48-1429 look close.



also would just starting my bike and letting it idle on full choke cause some gas to go into the airbox? over the winter i go out and start it up everynow and again, and let it warm up on full choke then shut her down. today i went out and seen some gas driping out the air box. i pulled it apart and had about a 1/2 cup of gas in the airbox. i did watch for gas coming out the carbs but there were non. i then pulled the carbs and clean them. all four float valves do have shiny wear rings around them but no groves that i could feel.
whats the best way to test them before putting them back on my bike.
also my bike starts up and runs fine with no smoke or anything.

[81xsproject]

I haven't finished the write-up yet but I can say that the Viton Upgrade does work. There is a link to Z1E for the part, but I bet you could use the cross reference list at the bottom to get them a little cheaper.

[thewiz]

well ...

If your carbs are original, they are BS-34 II, containing a threaded float valve similar to the ones you're seeing at Mikes XS. I'm uncertain if they are the correct ones though. Running on full 'choke' shouldn't cause flooding as it is not really a choke, per se, but an enrichener circuit instead.

I was gonna' say that I bought some gasket and float seat kits from PartsNMore last spring for 12 bucks ea. and NOW they seemed to be removed from their catalogue .... guess our bikes (like some of us) are gettin' long in the tooth, do ya' think?

I also checked OldBikebarn and BikeBandit ... bike bandit shows a kit for 19 bucks that looks right, Part #: 177280 and a more comprehensive one for 23 bucks. My local independent bike shop usually gets me a float valve by itself for between 10 and 15 bucks depending on the carb ..... in lieu of an expensive and possibly unnecessary replacement, and since your needles aren't grooved, Prom usually recommends that you take a little chrome polish and a Q Tip and polish out the seats a bit. After shaking the floats to be certain that one is not loaded and blasting the various internal passages with some aerosol carb spritz, set the floats to 25mm, make certain that none of the pontoons are binding on the carb body, put it back together and roll with it. You may wanna' consider inline filters and new fuel hoses too if you haven't already . Top it off with a half a can of Seafoam and a full tank of fuel and hopefully you should be good to go.

[81xsproject]

The ones from mikes do also work. Avoid rebuild kits. They will cost you 2-3 times the price depending on what route you go.

[thewiz]

Ok, 81, but ...

I think he is asking which of those PNs he mentioned would be best? Neither part listed suggests that it is for BS34IIs ???

[bigb9582]

yes THEWIZ i was also asking which part would fit the 79f.
partsnmore does have one with a gasket listed for 12 bux still, so that maybe my other option if the mikesxs one wont work.

im gonna clean everthing real good and put it back together and see what happens. already have new fuel lines/filters.

[thewiz]

Here's the deal ...

Glad you found the one at PNM .... I missed it while looking there for it, so I thought it was gone. There is a website, www.cyclewearables.com, that has a bunch of OE Mikuni and other carb part numbers (and presumably the actual parts too) where perhaps you could possibly X-reference those two MikesXS parts, if you're willing to do the work. Also they have a new float seat needle for about 5 bucks.

Seems like you should be able to ask MikesXS but I have read on this site that they aren't very 1100 friendly .... I haven't experienced that first-hand though.

Frankly, the mini kits I got from PNM were less than optimal as the float bowl gaskets didn't fit quite right .... appeared to have shrunk a millimeter here and there ... was dissappointing but the valves were fine.

[bigb9582]

cool thanx for the info.

just a update, i cleaned the carbs and have no overflow/leaks from them. left in sit for a hour with the gas on prime. put it all back together and went for a hour ride with no problems. checked it a hour ago still no overflow.

now i notice my petcocks are both leaking when on normal or resv. i already rebuilt them with new kits from parts and more last year. plus i torn them down and recleaned them and that didnt help.

so does the 46mm adapter plate seem like the right size for standard tanks? i think im gonna go with regular on/off petcocks and eliminate the vacum.

[thewiz]

That's the way we like a carb problem to end ... right on!!

I had the notion to replace the taps with a full manual set-up once myself. I believe there was commonly two different size adapters. The wider one fits a Std and the narrower fits a Special.

One more thing that can be done is that the 'waffle washer' under the chrome retainer can be slightly bent to gain a bit more tension and perhaps stop the leak that way.

IMHO, the vacuum taps, when sealed up good, work fine (and have for 30yrs.) They provide a foolproof way to shut off the fuel and keep the carbs from flooding.