choke seals

my choke seals are leaking and I think causing my chokes to virtually not work. where can I get new ones?

 

Nobody else has had to replace these?

 

Define what you mean by leaking?

Choke seals are not terribly important in the starting procedure. The choke is the simplest parts on the whole carb and even if there where no seals the choke would still work. Would run like cr@p though.

Now if your talking Butterfly shaft seals then that is a whole new ball game.

 

CHOKE SEALS?????

 

The little rubber caps that sit around the choke shaft. Looks like mini fork dust seals.

 

ok. Thanks HG

 

Those little caps are just dust seals. If fuel is seeping out then the choke plungers need to be removed and cleaned followed by the choke seats. There are no seals or orings, it's just a brass to brass seal.

 

That's what I thought!

Thay's how mine are anyway

 

Clean the dust covers with Armoral.

Likf the Valves and lube the shaft with Marvel Mystery Oil. The Marvel Oil will coat and protect those valves from sticking.

Lube the cable, shaft pivots and all the moving parts. You should be able to use the Enrichment Circuit to control the rpm while the engine is warming-up from a cold start.

Not just ON - OFF ... but, Variably controling the Enrichment to get a precise mixture and a "Fast Idle" adjustment; too.

 

In case anyone needs them, the butterfly shaft seals are now being sold at MotorcycleCarbs.com.
http://www.motorcyclecarbs.com/Butterfl ... s_C680.cfm

Z

 

At $5 a pop! Hummm... $40 for the whole set. Wonder where the price break is? Anyone up for a bulk order?

 

Sorry guys, I haven't been on the board in a while. Yes, the little rubber dust caps are what I'm talking about. Currently my chokes aren't working, I'm gonna tear my carbs down and try to clean it up.

I have two of the seals/caps missing and the other two aren't sealing too much. When I open the choke I can hear air going into or coming out of the choke shaft, when I close it, it stops.

My bike is a PITA to start cold, but once it warms up it runs almost perfect with an occasional hiccup when rollin on the throttle after cruising at a constant speed. I cleaned the carbs once when I got the bike because it wouldn't even run so I'm sure another go will help.

Hired_Goon - What do you mean it would run like crap without the seals? Just with the choke on or all the time. I'm guessing all the time.

 

There's two items in play. The rubber "Dust boot" that's exposed, surrounding the enrichment valve isn't air tight. That's to keep the shaft areas free from dirt and debris. Normally, a cracked or missing Dust Cover is not a performance issue, unless dirt contaminates the area and prevents free up-and-down movement of the valve.

The critical rubber part that WILL most certainly effect tuning and performance is at the bottom of the valve. At the business end of the Valve shaft is a larger cylinder which has a rubber valve seat. The seat is not unlike a faucet washer. When the spring-loaded shaft closes; the rubber seat seals-off the fuel supply to the Enrichment Valve.

If the rubber seat's ridge is worn-out; fuel will leak-by the supply opening and cause problems ranging from running rich to flooding-out and spark plug fouling.

To inspect the seat, you need to extract the whole valve assembly and withdraw the brass valve to check the rubber "washer" (It's a cross between a washer and a "Lipped O-ring").

I've never seen a split rubber valve end.

I have had to deal with:

Filth disabling movement.
Bent out-of-true shafts; binding.
"Hats" -- the "T-top" at the top if the shaft getting bent-over and hanging-up in the operating linkage (the forks that lift the Hats to operate the valves.)

Wrap the shaft with masking tape so it is not scratched or scored when attempting to straighten it.
Heat the Hat and >SLOWLY and GENTLY< urge it back into proper position. The narrow portion of the shaft will snap-off if suddenly, heavily-torqued to move it.

Remember ... whatever you need to do ... You're handling BRASS.

 

OK, cool. Thanx for the help Rick. I'll have to pull them apart and check them out. They aren't hanging up at all, and most of the time my choke will kinda work for a couple of seconds. Just incase I need to replace any of those seals at the bottom of the valve where can I get them?

After that, I just need to clean out the choke pathways in the carb and hopefully I'll have a nice starting bike for next season. I rode this thing for months and unless it was over 85* outside I had to warm up the motor with light bulbs to get this thing to start LOL

 

I took one of the choke valve assemblies apart and there is no rubber anything. Nor is there any sign that there ever was. It is a brass to aluminum contact. It doesn't look like it was meant to have an oring or anything in there. With the way the carb side is machined the extra gas would have to flow over the edge of the oring or be partially blocked in order to go to the intake. I pulled the other valves up and down and they are metal to metal too. I would think if there was supposed to be a seal in there that atleast one of them would still have it.

Is there anyone else who could confirm this? I just changed my sig. I have a 1980 XJ650.

 

Maybe I had the vision of the chokes on the 900 when I was typing. I'll pull one out of a set of Hitachi's for 750 Max and eyeball it for you.

Can't get to doing that until Big-Jolly parks the Sleigh on the roof, slides down the chimney and leaves me my lump of coal!

Tuesday; earliest.

 

Confirmed. I have a set of Hitachi's that I am rebuilding to sell on ebay. I pulled one of the choke plungers to confirm and it is a brass to aluminum seat with no rubber seals. Sorry about my earlier post that stated it was a brass to brass seat. I forgot that this brand of carbs doesn't have a brass seat for the plungers.

 

Thats cool, thanx to both of you. This really is a great resource with great people. :mrgreen:

But now the fact that the "dust covers" are actually the only thing keeping my bike from sucking in air instead of extra gas means that I have to find some sort of replacement for them or I won't be able to get my choke working. To compound that, one of the hats broke off one of the plungers and had to be jerry-rigged with some wire so even if I had a seal for it I wouldn't be able to get it to work right.

Does anyone know where to buy replacement seals and a plunger?

 

You can buy plungers from www.powerpartsplus.com but no price is listed for the seals...that means they're not available.

Start watching ebay for carbs, I suppose.

 

nope, the plungers are discontinued also. I think you confused the plunger springs for the plunger because of the way it is listed.

I guess I'll have to keep an eye out for a set of carbs if nobody has a source for new seals.

Thanx for all the help guys

 

OOOPS, sorry. I must have been looking at the wrong model.

Keep in mind that those plungers are something that could be fabricated at a machine shop. It might be kinda pricey, but the alternative is waiting for something to show up on ebay.

 

Actually right now my alternative is waiting for the money to show up. My biggest concern however are the seals.

 

I feel your pain...monetarily and part-wise. :cry:

Sometimes you can fab up a metal part to make do until you get a replacement...but small plastic and rubber parts are a different matter.

One suggestion would be to try and figure out which other Yamaha models share your set of carbs...and then look for those on ebay, too. I've had luck doing that.

 

just got done looking at ebay. looks like a few people have whole bikes that they have parted out. lots of stuff

 

Ebay can be a good source of plenty of used parts.....
just be careful. The only thing that I got burned on was a petcock for my bike, the owner claimed that the petcock had been professionaly rebuilt but when I opened it up it had old cracked and bad seals and parts.
Just remember they are NOT the parts store.


Good Luck

 

So I'm still not sure. Is it agreed that those "choke seals" aren't to keep out air in any way, and that not having them will not cause an air leak?

Cause when I was looking at them (several months ago) they sure looked like they might cause an air leak.

 

They won't cause any sort of a leak especially if the enrichment circuit ("choke") is off. The plungers are needle valves, once closed, they're closed. The rubber booties are more to keep crud out of the little valve assemblies than anything else.

 

I could have sworn there was another hole leading from the air chamber to the enrichment plunger area. I'll take another look when I have them off next weekend. Like I said, it was a long time ago!