Replaced Butterfly Seals

[jthiessen]

Hi all!
So I've replaced the butterfly seals on my carbs as I was having vacuum issues.

First of all, I was a little confused when I pulled out the seals and one of them seemed noticeably larger than the other three. (picture to come) The seals themselves seemed to be in good shape, so perhaps it was the single oversized unit causing the problem.

Now for a few questions:
1. What way do the seals go in? Bevel facing away from the carb body, or bevel facing in?

2. I dun gone and effed up some screws on the butterflies. Where is the best place to find replacements (in Canada)? I read that perhaps some Suzuki screws would fit?

3. I know there are ball bearings on the choke rod, but I also found one bearing that was a bit larger than those two. I have no idea where it is from, it was just amongst my carb parts while I was reassembling. Note: it could be from another project, I was borrowing some shop space from a friend.

Thanks!!

 

[jthiessen]

Would these Throttle Butterfly Shaft Screws work on my XS400?

If my carbs are stock would they be the same as an XS650's?
http://www.xs650direct.com/products-75.html
Throttle Butterfly Shaft Screws (Pk./4)
Fits: Stock Mikuni BS34/BS38 CV Carbs.

 

[rshutchinson]

I put mine with the bevel facing out. The vacuum should suck the lip tight against the shaft and help seal.

I used those screws on mine.

 

[xschris]

They come from the factory with the rounded part in and the lips facing out. I have had dozens of these carbs apart and they always came this way. It is the way I put them in when I rebuild a set.

 

[rshutchinson]

This will help as 'bevel' doesn't really describe them very well.

 

[xschris]

Yep

 

[rshutchinson]

Also, i've read many negative reviews of the Mike's XS seals leaking so I'd advise only getting OEM Yamaha ones, they still sell them. I got mine from a Yamaha dealer in town.

 

[xschris]

I have used mikes in the past on some xs650's and they seemed ok. But for the last few years I have been getting oem ones from a place on ebay.

 

[jthiessen]

Thanks for the pics, I did have them in wrong!

Now for a pic of my own, I have two washers left over after assembly. How embarrassing!

Here they are pictured with my drain plug.

I have no idea where they are from. They seem to be brass.

 

[rshutchinson]

They look like drain plug crush washers.

What recent work have you done? What size are they?

 

[JimVonBaden]

Thanks for the pics, I did have them in wrong!

Now for a pic of my own, I have two washers left over after assembly. How embarrassing!
View attachment 19417
Here they are pictured with my drain plug.

I have no idea where they are from. They seem to be brass.

washers for both sides of the fuel input pipe.

 

[rshutchinson]

washers for both sides of the fuel input pipe.

 

[jthiessen]

washers for both sides of the fuel input pipe.

No, I have those installed. Also they are too small for that application.

I took my carbs apart, cleaned the jets, changed the seals on the butterflies, dismantled the choke rod. Had the whole carbs apart...

 

[JimVonBaden]

No, I have those installed. Also they are too small for that application.

I took my carbs apart, cleaned the jets, changed the seals on the butterflies, dismantled the choke rod. Had the whole carbs apart...

In that case, they may be the washer that goes under the jet shown here in the middle, jet not installed:

See it here:

 

[BBS360]

Edit: suggested already.

 

[rshutchinson]

In that case, they may be the washer that goes under the jet shown here in the middle, jet not installed:

They look too big, both the OD and ID for the jets.


Are you sure they came from the carbs?



Needle valve washers? Bowl drain plug washers?