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Putting the carburetors back together

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Putting the carburetors back together

PostAuthor: Cykomiko » Mon Oct 29, 2018 4:03 pm

Hi all,

I just changed all diaphragms on my XV carburetors. There are in place as they should be.
It worked fine, apart for two little things.
1.One plunger goes down slower than the other. Not by much, but it is noticeable. Plungers color have turned from copper to brownish. Maybe it is the reason?? (corrosion? )
2. There is a tiny hole at the bottom of the plunger, right next to the needle. Does this need to be in a particular position when I put everything back together?

Thanks for your help on the matter. Glad to help with anything if I can!

Mika

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Re: Putting the carburetors back together

PostAuthor: Flyingdog » Mon Oct 29, 2018 5:02 pm

Cykomiko wrote:1.One plunger goes down slower than the other. Not by much, but it is noticeable. Plungers color have turned from copper to brownish.


Not familiar with the 500. What year is it? Far as the slide goes..could be one of the problems. Rub it down with a Scotch Brite pad, Brasso brass polish or even something like Turtle Wax polish usually helps. If you're gentle, #1000-1500 grit with water or some liquid works, too. Up & down motions only. There's really many ways to clean them up. If that's your only problem. Don't over look the slides' bore, too. Sometimes, if the diaphragm isn't installed correctly it can hang the slide.
All said and down, you're looking for the "Clunk" test when ya let the slides fall on their own. (And I'm not talk'n bout letting them fall on the floor) Be surprise how many get this wrong. :bg:
Do your carbs have the black hoses w/the black bulbs coming from the top of carbs? They need to be clear. Have been known to plug up. Absolutely needed for the slide to work right.

Cykomiko wrote:2. There is a tiny hole at the bottom of the plunger, right next to the needle. Does this need to be in a particular position when I put everything back together?


There again..is it Hitachi carb? Hitachis' have vacuum holes in the bottom of slides and they must face toward the cylinder. Yours? I will assume it's the same.

Someone more familiar with the 500 could verify. The year would be helpful to look it up.
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Re: Putting the carburetors back together

PostAuthor: bstig60 » Mon Oct 29, 2018 5:39 pm

Flyingdog wrote:There again..is it Hitachi carb? Hitachis' have vacuum holes in the bottom of slides and they must face toward the cylinder. Yours? I will assume it's the same.


These are Mikuni downdraft carbs...........
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Re: Putting the carburetors back together

PostAuthor: Flyingdog » Tue Oct 30, 2018 1:11 am

bstig60 wrote:These are Mikuni downdraft carbs...........


"As" with Hitachi, the Mikuni (w/ round slides..83'?) the vacuum hole goes toward the engine.
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Re: Putting the carburetors back together

PostAuthor: Jake » Tue Oct 30, 2018 6:38 am

Flyingdog wrote:
Not familiar with the 500. What year is it?


My resources tell me the XV 500 SPECIAL 26R is a 1983. The year is important for us to know as the 500 was manufactured at a later date.

Please add the year to your profile so no one has to ask in the future, not all members can determine the year by 26R.
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Re: Putting the carburetors back together

PostAuthor: Cykomiko » Tue Nov 20, 2018 9:36 am

Hi all,

Sorry for not replying earlier, but I hadn't been notified of your replies.

Many thanks, this is really helpful, and I had no idea of the importance of the hole's position (ahem...)
Cool, I'll undo/redo all again for they're not facing the right way... That means removing the membranes...

I did clean the plungers with wet 1000 grit, as you recommended Flyingdog (without seeing your post!), they came beautifully clean and shiny


My bike is a 1986 XV500 Special. No idea of the country of production. Carbs are Mikuni, that's for sure. I'll update as much info as I can before I ask more questions (which I need to do!)
Thanks again, guys. Love this forum.

Mika

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Re: Putting the carburetors back together

PostAuthor: Flyingdog » Tue Nov 20, 2018 2:08 pm

Cykomiko wrote: That means removing the membranes...


So, your new diaphragms had the locating ear? That's kinda weird, as all (new) diaphragms I've ever come across "did not" have the located ear/tab that's match with machined indent on the carbs' rim. Seemings how you can only get aftermarket diaphragms anymore. That's why ya gotta pay attention to those little vacuum holes. Very easily missed. Might be an over seas thing. Either way, sounds like you gotta a handle on it..hope all works well for ya.
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Re: Putting the carburetors back together

PostAuthor: Cykomiko » Tue Nov 20, 2018 2:54 pm

Yep, good guess, they have the ear. Funny that you say that they don't have it in the US... But I managed to do the whole thing again using a guitar plectrum to push the lip back in without damaging it. Pretty easy.
Now my carbs are almost clean, sliders shiny, everything moves smoothly... all ready to go! I am just waiting for parts to try to fix the manifolds that are old and a bit cracked. I'll attempt doing it with high temp liquid gasket and shrinking tube. Buying the right ones new is just ridiculously expensive here.

Thanks again for all the help everybody provides here. There is so little out there about the XV500 that this forum is a blessing. I just hope I'll be able to help someone in return one day!

Right, now I've got a post to write about electrics...

Cheers!

Mika

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Re: Putting the carburetors back together

PostAuthor: Flyingdog » Wed Nov 21, 2018 10:12 am

Cykomiko wrote: There is so little out there about the XV500 that this forum is a blessing. I just hope I'll be able to help someone in return one day!



I'm sure you will, the more hands-on you get with the 500. Always sooo much better stuff coming from owners of a particular bike. Specially ones that are not that widely questioned about. :bg:
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Re: Putting the carburetors back together

PostAuthor: bstig60 » Wed Nov 21, 2018 2:55 pm

Flyingdog wrote:
Not familiar with the 500. What year is it?


FYI: the XV500 was only sold in the US in 1983 and was the precursor to the XV535 which begin selling in the US in 1987. Both had downdraft Mikuni Carbs. The 500 was sold in other countries, including Canada until the change to the 535, so there are a lot of them around.
Bill
"It´s a friggen motorcycle, it´s not supposed to be comfortable, quiet or safe. The wind noise is supposed to hurt your ears, the seat should be hard and riding it should make you s**t your pants every now and then. "

Please take the time to edit your profile to show your location. City, State/Province and Country. It is easier to help you if we know where you are.

SERVICE MANUAL DOWNLOAD LINK
http://viragotechforum.com/viewtopic.php?f=220&t=31501#p279545

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Re: Putting the carburetors back together

PostAuthor: Oldstreetracer » Sun Mar 17, 2019 12:51 pm

Cykomiko wrote:Hi all,

I just changed all diaphragms on my XV carburetors. There are in place as they should be.
It worked fine, apart for two little things.
1.One plunger goes down slower than the other. Not by much, but it is noticeable. Plungers color have turned from copper to brownish. Maybe it is the reason?? (corrosion? )
2. There is a tiny hole at the bottom of the plunger, right next to the needle. Does this need to be in a particular position when I put everything back together?

Thanks for your help on the matter. Glad to help with anything if I can!

Mika

Would you be able to tell me where you bought your rebuild kit, I’m having some trouble finding a kit that has more than just o rings and bowl gaskets?

Thank you!

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