working on float valves up side down?

marp68

marp68

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I most probably have a small leak in the float valve, due to old stuff or bad adjusting. It doesn't leak right after switching off the engine, but after one night it has leaked from both chambers.

Would it be possible to work on the float valves up side down, just removing the float valve cover? SO that i don't have to remove the carbs. To inspect and remove possible old stuff or adjust the the float valves.

/Martin
 
Don't do it. It seems easier but it is NOT. Just my two cents but pulling the carbs is always easier in the long run. It's funny but I was into KZ1300s for quite awhile and the three 2 barrel carb set up could be out and on the bench in 15 minutes flat with practice. Less time than I think an XS takes. But the XS is not bad. The Honda FT500 was a nightmare, a stinking single and half the fricking bike had to come apart to get the carb out. Grrr. Anyway you cannot do a decent job of checking float height with the carbs on the engine and you will be chasing lost screws and bunging up Phillips heads etc. Poor light, twisted neck, trying to see whats up blah blah blah. Yes I have tried it not on an XS but similar and anything beyond changing a main jet on a carb that has already been gone through is hopeless when they are in place. And even that is debatable easier on or off.
 
Hello Martin,
The float height is easier done with the carbs off for me. But I'm not cleaning/adjusting the float valve seat that often. I do however have to clean my pilot jet two or three times during the season. For that the carbs can be left on. A cut down socket driven allen and a thumb rachet works well 4 me. Swapping the phillips heads for allen heads is a reasonable mod. If you search the old 650rider site XSJohn had a thread with really good pics showing the floats being adjusted with the carbs on. The problem for me was the tang of the float needs to rest on the spring pin in the needle not depress it. I can't tell about the pressure I'm applying when pushing up.
 
Are you turning the petcocks off? The float valves are not meant to be a long time storage shut-off device, that's what the petcocks are for.
 
Yes, after a ride I turned the petcocks off. I also bent the overflood tubes upward, so that it wouldn't drop on the floor. The day after they were filled.

Today I emptied these rubber tubes and bent them upward again. If they are filled tomorrow, it would mean that the float houses have been filled again, because both the petcocks and the float valves leaks. I do plan, though, to check the petcocks by removing the tubes connected to them and see if they really leaks. Where can one easily buy petcock rubber washer?

I recently bought the bike (one week ago) and since it seemed difficult to remove the carbs (don't want to destroy other things), I thought that maybe I could scrap off dirt or adjust the height up side down, just removing the float house caps. Even though it's a bit more difficult working up side down, is it easy to damage something working this way, you think? Have never actually worked on carbs before. I have the clymer manual, so it would just be to follow the removing description, I assume?

Or if someone has the link of the thread weekendrider talks about above, that would be great. I could at least try it. How can I search the old xs650 site he tlks about?


/Martin
 
XSJohn had Allen bolts holding his float bowls on to make it easier to do this. If you were using the clear tubing method on a later carb, it might be easier to do on the bike than repeatedly removing and installing the carbs. I put Allen bolts on mine because the Phillips heads were messed up. Home Depot has bolts about 1/16 over and little lock washers to go under them (couldn't get the washers off of the original screws easily).
 
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I'm down to 5 minutes or less on carbs off and on the bench...easier to adjust and check and clean everything. Of course, I'm not running airboxes, never even seen one, so don't know how long that takes.
 
Worthy restatement.

Last winter I had a big puddle of gas but my petcock doesn't normally leak. I figure moisture must have frozen on the diaphragm and forced it open. The gas seemed to have run out past the left air box cover, down the cables that go to the generator and pickup, and gas was pooled under the round cover. If I'd started it, might have had a good fire.
 
From what he says the petcocks are shut off. I think the problem is both leaking petcocks and dirty float valves.
The easiest way to fix the carbs is to remove them, much easier to clean the carbs and set the floats on the bench.
Pulling the fuel hoses off the petcocks and using longer hoses to run into something to catch the fuel in is a good way to check the petcocks. For flow as well as leaks.
Mike's XS and his European partners sell rebuild kits for the petcocks. If you take one petcock apart and take the washer with you to a bike shop they may be able to get one that matches.
On mine the handle part was very rough where it was against the washer. I polished it on very fine sandpaper to smooth it.
 
Might be a good time to go back upstream to the fuel tank. My bet is there is trash in the tank, making its way downstream and tearing up seals, gaskets as it goes. Fuel filter never hurts.
 
Yes I think so too.

I looked at the part chart. The rubber washer for the petcock, is it called "wave washer"? Anyone knows the part number of it? I intend to order it and replace it first. Then I can switch the petcocks off and start working on the floats without having a lot of gas flowing.

At mikes I found this rebuild kit. Would it maybe be a better idea to change all things? Couldn't find only the rubber washer. http://www.mikesxs.net/products-34.html#products

I'll definitely also put on gas filter, both after and on petcocks. Saw a fuel filter at mikes that you put on the petcock pipe up in the gas tank. Seemed good.

Or anyone knows where to order in Sweden or at least Europe?

I also think that it's best to remove the carbs before working on the float area. But it seemed a bit tricky to remove all things. Side panel, air filter, gas tank, tubes etc. Maybe I'll wait unitl the winter comes and I have more time to do it nice and calmly...

/Martin
 
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Or is it the plate with four holes in that one should change if it leaks?

It leaks internal, down the tube so to speak, and not outside the petcocks. So which part to change then?

In a thread someone said it may be fixed by flipping the flat round plate with four holes in.

M
 
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After it's open you have to figure out what would wear out and cause it to leak.

If you go to any Yamaha parts dealer's website, like babbittsonline.com you can select a year and pull up a fiche for your year that will also get part numbers. If what you have inside is different try other years. While you have the petcock taken apart if you don't see anything damaged clean it real well with carb cleaner and grease lightly the surfaces that turn against each other. Put it back on the tank and shut it off and see if it drips. Maybe don't have to buy anything. Some of the rubber parts inside can be fragile, so careful.
 
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Yeah the rubber "washer" with 4 holes. Flipping it sometimes works but seeing it often gives the answer as to reuse. A quick shot of brake cleaner and blot it dry might soften it a bit and give it a few more miles of use. Rub it gently across some stiff paper or cardboard on a flat surface to "shine it up" also and +1 on a light coating of grease, but in the long haul replacement is best they aren't that expensive on fleabay.
 
Okej, thanks.

I'll start with trying to clean, rubb, grease and flipping the rubber, if it's not already completely beyond rescue.

Would it cause any problems (oil leak or other) putting the bike down on one side, to make it possible to work on the petcock without emptying the tank first? It's almost full now...

Btw, what's the "wave washer" for? Sealing tap?

m
 
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Yes, the wave washer is for sealing the tap. If it was bad or missing, the tap would leak on the outside. It pushes the petcock arm against the 4 holed rubber disc and makes it seal.
 
Just run a hose/tube off the petcock to a gas can/milk jug/container of choice, to empty the tank.
Leave the petcock on the tank, that helps hold it while you fight with those little phillips (alllen/socket head replacements can be had) in the face plate. Under the face and over the selector(valve handle) is the wave washer, then the selector/valve, under that in the cupped area is the valve washer( 4 holed rubber). When you take it out look on the bottom side ander you'll see little ridges(molded lips) around each hole. This is your seal.
It get worn away by the selector on that side. Turn it over you have new lips/seals.
Sometimes it works, sometimes it doesn't I think because you also wear it thinner or it shrinks or ...... That usually results in leaking on the face plate side.

Scanning the thread again I don't which fuel valve you're working on?
 

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