Ebay slide diaphragms don't fit...

Hey- just thought I'd post to save others the aggravation- the SD-3 slide diaphragms on ebay were measured by the sellers and they thought they might fit my 550's BS28 carbs- but they don't. The diaphragm fit the piston perfectly, but is about 2 or 3 mm too wide to fit in the carb body channel properly. So- now I gotta send them back.

Also, I experimented with several different "compounds" from plasti dip to different offerings from Permatex to repair these diaphragms- and nothing seems to keep them very pliable. The "Form a Gasket 3 (aviation grade) is outstanding stuff though- it doesn't harden and stays tacky forever but works great- (I even used it on my gaskets on the truck since it is good up to 400 degrees.)

2 of the diaphragms really are toast- and cracked badly. So- guess its time to just bite the bullet and get replacments. :roll:

 

cheaper to pick up a whole rack off eBay; you can often find them for under $100.

 

Yeah- Ive been trying to keep an eye on ebay for some where the seller says the diaphragms are OK- but most won't take the hats off. I guess they figure that way they can turn 'em without "knowing" the diaphragms are full of holey holes...

 

I bought two racks, one supposedly "off a running bike" and "gone thru by a pro" NOT but that's another story; plus another rack history unknown; and the diaphragms are (mostly) fine (except a dumbass PO "missed" with a locating tab and sheared it off one.) If you spend $30-$50 for a bank of carbs and get just two good diaphragms plus all those spare bodies and bowls you're still WAY ahead.

 

Here's my question: knowing that the diaphragms won't fit the BS28, would they fit another model of Hitachi or Mikuni carb native to the XJs?

No, I don't need any, but I'd be curious to know anyway.

 

Actually- the ebay diaphragms WOULD fit some other XJs. But all I ever really found were for the 34mm Mikuni carbs- which apparently were more common and used in other makes. The ones I ordered were known to fit a honda vt500 and several other bikes, but NOBODY could cross reference to find out what I could substitute for my 4g0-14940-00 diaphragms.

Its crazy- I even spent time on the phone with Yamaha Corp about it- and they said that they weren't able to cross the part to different bikes because the part number is model-specific basically. So, I asked them if a 3H5-14940-00 would fit my bike they said "that fits an SR250 and the XJ900R." I asked again if it would fit my bike and they told me "what you need for your application is a 4g0-14940-00." When I asked if I could substitute a part number for another yamaha bike that used these carbs since these diaphragms were "no longer available" according to my dealer and most retailers, I was tod "They are still available- just not in the USA" and that I could have one, for the sum of $260 plus shipping from Japan. I about fell out of my chair- because I need 3.

The ebay sellers were very nice and measured them for me, and it looked like they would work- but when I was threading one into the channel it wouldn't go- it was barely too large to fit. It fit the slide piston itself perfectly and with some supa glue I probably could have MADE them fit- but then the piston wouldn't have had the necessary travel within the carb. So- they gotta go back. Its such a simple part- with an OBVIOUS limited lifespan due to its construction, what it does, and the environment it must operate in. You'd think they'd keep an endless supply around for the eventual need for all of us to replace the things...