Vm22/210 pilot jets question

[oldskoolcarbs]

I have taken pilot jets out of 7 different sets of TYPE I AND TYPE II XS650 CARBS, out of 7 sets, some look carbs look to be unmolested, none of these pilots have the air bleed holes as pictured in the carb manual posted in the tech part of the forum. Is this a mistake in the manual or has some one put the wrong pilots in 7 sets ?

 

[oldskoolcarbs]

more detail

 

[oldskoolcarbs]

Rex, notice that JIS BIT TAPPED IN THAT NUT DRIVER, REX sent me 3 or 4 sets of those , life savers on these metric Phillip head screws

 

[grizld1]

Many OEM VM22/210 type jets were produced without bleed holes, all aftermarket jets have them. The only thing that signifies for replacement is the location of the metering restriction (in the thread end for VM22/210, in the barb end for BS30/96).

 

[oldskoolcarbs]

Thank you so much !!!

 

[5twins]

No, it's not a mistake in the manual or the carbs. Those are what we "affectionately" call the "no hole" pilots. It has to do with how the pilots are mounted in the BS38s (in the bowls) and where they are fed their fuel and air from. Pilots normally get their fuel through the head and air is fed to the side through those bleed holes. It doesn't work this way in the 38s. They get their fuel from the bottom and air from the bottom or top depending on the pilot jet type. The bleed holes on the sides are not needed but normal pilots with the side holes will work. All I can figure is Yamaha saved a few bucks by ordering large batches of pilots without the holes. They would be easier to make, eliminating a step in the manufacturing process, so probably cost less.

Another question that arises is why did basically the same 650 motor have pilot sizes in the mid 20s some years but up in the mid 40s for others. That has to do with the pilot jet type and what it flows. The VM22/210 pilots flow straight fuel and air is added above them so they are sized smaller .....

The BS30/96 pilots on the other hand, are fed both fuel and air from the bottom so they flow an already made fuel/air mix. They need to be bigger .....

The float bowls are different in the way they deliver the air to the pilot. You must use the proper pilot style in the bowl that was made for it.

Normal pilots with the bleed holes are really all that's readily available and thankfully, they work fine in these bowls. If you really wanted a VM22/210 no-hole in a larger size for mods, you can source a #30 from XS500 carbs.

 

[oldskoolcarbs]

5 twins, thanks for the info, Rex actually sent me a hard copy of that manual back in January that you co wrote..I am just getting back into these xs650 carbs and all the ones I have done have been for stock Bike set ups, so re jetting was not necessary .. I am re-jetting a set now for pods and exhaust and i am putting #30 pilots in from exactly what you said a xs500 set of carbs i have.. i started reading the manual and seen the bleed holes so that is what threw me for a little loop there ..learning all the time,, thanks for taking time out to post that great info.. This is the most detailed forum as far as post, info and people DEDICATION TO A SWEET BIKE, glad to be here

 

[5twins]

Well, I'm more than glad to help and you're providing a valuable service to the 650 community. Just like we all can't be brain surgeons, not everyone can properly clean, rebuild, and tune carbs. If you have any more questions, feel free to ask. I realize some of this detailed carb info is above and beyond what the average 650 rider needs or even wants to know, so you can send me P.M.s or e-mails if you like.

One thing you could do for me. I don't really have any good pics of the early 2 cable carbs. Maybe if you get some to work on, you could send me some. Full size, full carb views from front, back, sides, etc. would be great. Then I could crop, label, and use them in posts and maybe add some to the carb guide.

 

[oldskoolcarbs]

Yes thanks again for the info, here is a pic of cleaner bowls if you want to use for the above illustration ..I have a set of earlier 2 cable carbs that I have not rebuilt yet..When I get them done you are more than welcome to use the pics OR ANY of my pics for that matter..

 

[5twins]

Oh my, those are wonderful. Try as I might, I never get mine looking that good. I've set up a small soda blaster and it gets things very clean but they don't shine like yours, lol.

 

[5twins]

OK, a little work in the Paint program and the winner is .....

Thanks Oldskool, good pics speak more than a thousand words.

 

[bluebikerblan]

This has been a very informative thread thanks all. I'm not sure who deserves the credit for this additional labeled float bowl picture below but; it helped straighten me out a bit and I thought it deserved being displayed with this thread as well. Origin anybody? It's a repost of someones? Thanks, I thought it might be useful to have them in the same place and credit someone I'm not aware of?

Griz, 5twins we'ed have you bronzed if....we still didn't need your help almost every day! Blue

 

[retiredgentleman]

Hey blue; that float bowl looks familiar...........yup that's mine. Great effort by 5twins and grizld1 as usual

I'm trying to picture 5twins and griz bronzed..................ummmmmmm.............for sure we should do that

 

[oldskoolcarbs]

5twins pics soon of the 2 cable style

 

[grizld1]

Bronzed, RG? I appreciate the thought, but you couldn't get me into a tanning salon at gunpoint.

 

[oldskoolcarbs]

http://s591.photobucket.com/albums/ss351/wildmanv65/black%20xs650%202/

 

[5twins]

Thank You Oldskool, those are wonderful. 1973 set I'm guessing? I was recently given a set to look at. I haven't photographed them yet as they need cleaning. One of the things I want to document is the different external appearance of the float bowls. They're all notched out around the main jet tower.

May I ask what you are doing with the vacuum pump in the one pic? Is that a float needle and seat seal test or something?

 

[oldskoolcarbs]

i actual have a reaming tool i had to use on these float bowls,, i used dielectric grease to verify that the bowls were seating flush all the way around.. these bowls were being held up a little in the center, did not want to take a chance on not sealing anywhere so i had to "kiss' the center of the bowls that hold the emulsion tube in... the mighty vac is checking for a good seal within the fuel feed,, if it will hold vac it will definitely hold back f liquids/gas

 

[XSLeo]

I recall talking about the early carbs having a raised floor venturi. In the second pic second row, you can see how the floor of the venturi comes up very close to the slide.
I think this helps increase the air flow across the port in the slide and the needle jet. This increases how quick the slides react to vaccum differences. Along the lines of drilling the port.
The increase of air flow will draw fuel up through the needle jet quicker at the low to medium slide lift. This will richen the mix a bit, possibly giving an increase in power at these times.
I think they stopped doing this because it was cheaper to make the venturi round.
Leo