Why you should replace butterfly (throttle shaft) seals.

silicon paste not spray for the o rings

 

Yes. But not sure how long I should have worked at it. The butterflies seem to snap shut quite easily before installing carbs. However, after everything heated up they seems to just gum up and hold at 4000rpm. I used 2 #11 rings on ech side of carb and applied silicone grease to all of them and the shaft. Maybe the silicone was crap.

 

when the carbs are assembled into a rack they can get twisted and bind up, maybe that's all that's wrong
or they are trying to close and the sync is off, that could easily get you 4K

 

I am going to lean towards the twisted rack. I used a 1/2" piece of plexi to keep them straight, but could have missaligned them.

Time to pull them out again. Fun times

 

its not twisted .... (ignore the numbering sequence on the rack)

I also re did the bench sync to where the butterflies are set to only show the slightest edge of the first hole


I took video of butterflies closing, but couldn't get it loaded. There still not closing as fast as they should be. They almost seem to be hanging just before seating

 

I originally used one #11 X ring and one stretched #10 O ring per side but found the two rings together slowed the close of the butterflies. Removed the O rings and all is well. It might be the total width of the two rings make for a slightly tight fit. The original seals are not any wider than one X ring anyway.

 

the butterflys might be rubbing on the sides of the bore.
i had the linkage hang up on a manifold clamp at about 3/4 throttle one time, glad i found that before the first red light

 

Did you use Vitron O rings?

 

Who made the o-rings? Go too cheap and they won't consistantly be to spec. If the diameter of the core is just a tad too big, then the ID and OD will be off.

 

i wouldn't expect a #11 X and a #10 O to work, the OX would fit more like oX
i never tried Viton, if the Buna-n ever fail i might
we have thrown out harbor freight orings, some places they work fine but not always

 

I had 2 Buna-N on each side of carb. Everything I tried didn't work.

So I removed 1 oring from each carb. The butterflies seemed to snap back quickly. So I put everything back together, bench synced, installed carbs and tested ... again. It still has a slight hesitation to return to idle and now its backfiring like crazy.

I think its time to purchase the correct seals and quit screwing around ... at this rate I will be parking it for the winter.

 

None of the auto parts or hardware stores in Santa Fe have any idea of what
A #11 "0" ring is. I ordered " 0" rings from Grainger online and tried them
in a carb but they made the butterfly too tight to function. Where do the #11
"0" rings spoken of here come from ? I ended up getting real throttle shaft
seals from xj4ever.

 

the #11 has to be worked when installed. mc mastercarr may be a supplier but 11 should be 11.
also has been recomended that 1 oring with 1 #11 x ring be used,
and silicon paste not spray.

 

How much are the throttle shaft seals? This is my next job. No point in rebuilding my motor and not doing this.

 

Check xj4ever catalog , I cannot recall how much I paid , but it is worth it!! I know S&H to Europe might be expensive , but these seals fit perfect . I tried the #11 O rings on another set of carbs , I'm just not sure exactly if they would work compared to stock seals. I know some claim no issues with them , but who's to say.

 

I might get them from Chacal, need to get vaccum gauges too. I assume I need eight of them? The #11 O rings have two profiles I think. Need to do some more research into this before I start thanks. Where in Europe are S&H based?

 

S&H = Shipping and Handling.

 

My brain is not working right tonight k-moe lol.

 

Try more single malt. That usually helps.

 

Yes I quite like a wee dram in moderation of course .

 

The #11 o-ring is a 5/16” ID x 7/16” OD ring. Bought mine in a kit of rings you should be able to find at any Auto store. Just may not be called #11.

 

What is the difference between an o ring and X ring and do the o rings go in first to the bore. New task for me doing this. I assume the X ring is it's cross section.

 

The X-ring is square like the original seal. I tried the X-ring in first followed by a tightly stretched #10 O-ring but my butterflies were not closing in a timely fashion so I removed the O-rings. The original rings are no wider than the X-rings and there was only one of them per side, so why add an O-ring?

 

Cheers Huntchuks I will use the X rings then two per carburettor. Apart from the fuel T connector o rings are there any other seals etc I should replace when doing this? I will need to read up on taking the carbs to Church.

 

The original solution to not being able to source the original seals was to use o-rings in tandem, because they are not as wide as the original seals. Being too narrow causes the o-rings to be able to roll and leak. One thing to keep in mind is that there are half a dozen standards for sizing this type of seal. The #11 o-ring used in this application has to conform with U.S. standards. A #11 o-ring from another standard will not work.

TLDR: now that proper throttle shaft seals are easy to get again, buy them and enjoy how they fit perfectly.

 

McMaster-Carr ain't interested in shipping to Europe, period.
Nope, not doing it, despite me asking nicely.
Over the last few years I missed out on several things they had in stock that would have cost much more here, but eventually the Irish Post Office opened a drop-box in New Jersey, and I bought a 100-pack of #11 x-rings, laughably cheaply (even allowing for the forwarding cost) compared to what jokers here wanted for them.

 

I've never had any such issues during my 40+ y of riding with any bike. Perhaps because, on occassion, I spray all that moves with some lubricant?
Never had to change any wheelbearing or similar even with wheels that ran 200K or more and I ride/rode my bikes on any occasion also in wintertime with salt and stuff.
Maintanance is always on par because I don't spare my bikes, they are there to be used as I see fit and the bikes always slept outside, covered but still outside.
So I'm quit curious why several people seem to have those problems.

 

I am desperate for a set of shaft seals for my build nearing completion here in uk, xj4ever can`t send parts coz of some problem with change in our import system. I also nee one idle screw (coarse thread for hitachi) can anyone help?

 

I'm originally from England i live in Colorado now
I need a set as-well not sure how to actually buy them from xj4ever

i have a spare idle screw
for xj750 maxim

 

hi - is it the coarse thread/hitachi as the left one in the photo? if so would like to buy (and to move to colorado!)

 

info@xj4ever.com you can contact Chacal for the parts you need.

 

I will check in the morning

 

Chacal service is great , I just bought another set of butterfly seals from him. The correct seals are best , but in a pinch you can use two paired up #11 buna "O" rings , I rebuilt the set on the Johnny Cash bike using these so far work fine , I used buna O rings on the fuel rail .

 

Why is it so hard to buy the seals is there some way i could click on something that says buy them
or add to cart
or is there a site i can go to.
whats a chacal and why does he have all the throttle seals

 

email info@xj4ever.com

 

It is.
Email info @xj4ever.com

 

It's not hard. Len has a simple and inexpensive way of selling parts. Atart a conversatin with him using the forum software, or email hom at XJ4ever.com.

Why does he have all of the good parts? Because he's better than Yamaha at keeping old parts in stock.

@chacal is a sponsor of this site, and a forward-thinking parts supplier who bought a lot of "obsolete" stock when the dealers dumped them. He also has made efforts to get reproduction parts made, as well as improved parts for some applications. He is a passionate XJ owner.

Honestly, Len (Chacal) is the main reason why XJ parts are still available.

 

In the world of vintage, (anything)... vintage that needs parts, to a dealer is not a money maker because parts are not stocked anymore. So Len ( Chacal) is the only xj parts dealer i know of. Great parts and at times comes with installation instructions

 

if he would relocate to north yorkshire that would be even better

 

hi foxy did you have any luck ?
cheers
steve

 

I checked with three dealers to see if they could get seals .They did try found the part number for them 2 even called the main Yamaha distributor where ever that is and the are Discontented an no longer available. So Chacal is the only one to get seal with out using O rings.

 

You have to remember that these bikes are spring return throttle, any stiction is potentially catastrophic, the original spec seals are to be preferred.
Having a supply of genuine spares without paying transport, import taxes, handling charges - worth it's weight in Gold.

 

the part number is out there someplace. may want to try a carb parts vender for your brand os carbs as the carbs are not yamaha property.

xj4ever sells the seals. best for US members as the uk gets fees from bringing them in to uk

 

I wrote the part number down some where for the seals from a dealer just cant get them. they even looked a carb rebuild kit. docent come with seals they don't make a master rebuild kit. they said some complete kits have every thing to rebuild or remanufacture a carb. But not the Hitachi 33 they even tried looking it up thru other bikes like Kawasaki and Honda that used these carbs.

 

just email Len at Info@xj4ever.com he has oem and aftermarket seals

catalog
www.xj4ever.com

 

Thanks all, now I know I will need another tear down, sprayed carb cleaner near shaft ends BOTH reacted plenty. ALSO after doing much battle with these 40 year old Hitachi's I thought I had them rebuilt.....I installed a single carb intake manifold and tested each carb and found one still was still badly plugged. I wish I had an bike just set up to test these carb rebuilds and now looks like I do.

 

What are the main symptom's to look for seal failure on the throttle shaft ?
Grainger has an O-Ring-Lubricant 1RGZ6

 

The main things would be runaway idle or RPM's not wanting to come down after a throttle blip, things like that due to air leakage causing a lean mixture. Silicone works well as a lubricant.

 

today is my day day doing this, but...just wondering how to open my mikuni no. 2 carb: on this one no clip or nut, neither right nor left