glennpd
4 bikes, 4 dogs, 1 wife
Thanks, I will try a small drill bit. If the screw is brass it should drill pretty easy. Thanks for the suggestion.
Glenn
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(BS series) Throttle Seals: Who's done 'em, who needs to?
- Thread starter DirtyErnie
- Start date
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- Tags
- carburetors technical
Thanks, I will try a small drill bit. If the screw is brass it should drill pretty easy. Thanks for the suggestion.
Glenn
oldskoolcarbs
XS650 Addict
i have found 2mm x 7mm id O'RING to be a good fit, no binding nice tight seal and the plastic spacer holds it in perfect
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Sketch the plate position before you start so you know where the stamped mark goes. I have doubled up the 4 sided "o-rings" from mcmaster carr seems to work well. +3 when backing out a screw either use the impact hammer or lots of down pressure then start adding twist till you feel that sweet little clink of the threads releasing. It's all about stability, the carb has to be blocked so it can't move and backing up the shaft is a real plus. If anything can wobble you will strip the slot. A low table lets you get steady weight/pressure over the end of the screwdriver while applying twist. An assistant to hold the carbs is not a bad idea. Once you have the plates back in and the screws lightly seated. Lightly snap the throttle closed a time or two, tighten and recheck, there should be very a small uniform amount of light around the plate looking through the throat. If you are a known screw head stripper, best to leave this project to others...... because you can go from bad to worse.
Like Blue said.. the JIS drivers are perfect for the butterfly screws! I can't believe how much better they work over a standard phillips #2.
bluebikerblan
Geezer
Hopefully this post does not hijack the thread but adds to understanding why US "Phillips type" screwdrivers "cam-out" when they are applied to JIS cross-point screws....
.......................JIS type S Cross-point versus PHILLIPS.................................
A little known 'troublesome' standard in the US, the Japanese Industrial Standard (JIS for short) is a widespread set of manufacturing standards.You can never tell just where you will encounter products made to them and when conflict of such part design and your tools will arise, it's everywhere. Most everything of Asian origin is going to be compatible with JIS specifications. One such conflict of design frequently arises when our western "Phillips type screwdrivers" are used on JIS cross-point screws & fasteners. Your standard Phillips screwdriver 'hangs up,' and doesn't feel quite right. The Phillips driver won't go into the JIS Screw all the way because the corner radius of the screw is smaller than that of the Phillips screwdriver! This is the primary cause of what we know of and feel as 'cam-out.' It's a result of poor engagement of these incompatible designs. Unnecessary wear and damage inflicted on the fastener, tool or both.
In essence... we here in the US are trying to work with screwdrivers and driver bits that are shaped like the first two figures and so are trying to get them to remove or install screws and bolts that need drivers designed like the next two figures. The rounded double beveled "Phillips" edge into the comparatively sharp single beveled JIS hole just doesn't work right. Cam-out is the predictable and frequent result. Round peg.....square hole! JIS driver or bit into JIS cross-point....hand in glove! Long lasting powerful proper engagement.
Cross-point Screw and Driver Design Characteristics
..................US Phillips..........................................JIS Type S..........................
............. (See Photo Below)..............................(See Photo Below)....................
There are a few places you can get JIS type screwdrivers for proper fit to JIS type fasteners but not many. Moreover, until very recently, none that I've known of from whom to source 1/4" hex drive JIS bits. The Vessel Company of Japan is a source of both high quality tools and industrial bits. JDV Products,Inc. Fair Lawn, NJ is their exclusive North American distributor. www.vesseltools.com 201-796-1720 If anyone would like I have the specific product call outs of both 1/4" hex drive bits for both slotted and cross point driver bits.....yes folks the JIS standards affect slotted drivers too! Blue
.......................JIS type S Cross-point versus PHILLIPS.................................
A little known 'troublesome' standard in the US, the Japanese Industrial Standard (JIS for short) is a widespread set of manufacturing standards.You can never tell just where you will encounter products made to them and when conflict of such part design and your tools will arise, it's everywhere. Most everything of Asian origin is going to be compatible with JIS specifications. One such conflict of design frequently arises when our western "Phillips type screwdrivers" are used on JIS cross-point screws & fasteners. Your standard Phillips screwdriver 'hangs up,' and doesn't feel quite right. The Phillips driver won't go into the JIS Screw all the way because the corner radius of the screw is smaller than that of the Phillips screwdriver! This is the primary cause of what we know of and feel as 'cam-out.' It's a result of poor engagement of these incompatible designs. Unnecessary wear and damage inflicted on the fastener, tool or both.
In essence... we here in the US are trying to work with screwdrivers and driver bits that are shaped like the first two figures and so are trying to get them to remove or install screws and bolts that need drivers designed like the next two figures. The rounded double beveled "Phillips" edge into the comparatively sharp single beveled JIS hole just doesn't work right. Cam-out is the predictable and frequent result. Round peg.....square hole! JIS driver or bit into JIS cross-point....hand in glove! Long lasting powerful proper engagement.
Cross-point Screw and Driver Design Characteristics
..................US Phillips..........................................JIS Type S..........................
............. (See Photo Below)..............................(See Photo Below)....................
There are a few places you can get JIS type screwdrivers for proper fit to JIS type fasteners but not many. Moreover, until very recently, none that I've known of from whom to source 1/4" hex drive JIS bits. The Vessel Company of Japan is a source of both high quality tools and industrial bits. JDV Products,Inc. Fair Lawn, NJ is their exclusive North American distributor. www.vesseltools.com 201-796-1720 If anyone would like I have the specific product call outs of both 1/4" hex drive bits for both slotted and cross point driver bits.....yes folks the JIS standards affect slotted drivers too! Blue
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oldskoolcarbs
XS650 Addict
REX/BLUE turned me on to these 2 years ago,, a life saveR no more stripped screw heads.. i use the JIS bit in a cordless drill to disassemble carbs, works perfect....after 2 years, 300 SETS LATER, no sign of wear on the JIS BIT .. UPDATED MY SEAL REPLACEMENT INPUT, 2MM X 7MM IS A VERY GOOD REPLACEMENT, GOOD FIT
McMaster Carr? Their part number? TIA
Thanks for participating on the forum OSC.
ann0yed
XS650 Addict
Just replaced my butterfly valve seals this morning on my BS38s, it was super easy and only required a screwdriver. Finally my bike idles properly, I had to back out the idle screw several turns once I fired the bike up!
bluebikerblan
Geezer
Just checking....You do understand that we're referring to the two seals one on each side of the throttle butterfly shaft of each carburetor? Those butterfly plates that have to be accessed with the carbs off the bike and removed by removing the two each little cross-point screws to remove the throttle shafts to replace the throttle shaft gaskets? Blue
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ann0yed
XS650 Addict
I got mine from Mikes XS. I had to turn the idle way up to get my bike to not stumble and quit when idling at a light. Determined it was the throttle/butterfly valve seals with some carb cleaner. Just for good measure, also applied some silicone to the carb boots (JBM) which were also an air leak source.What butterfly seals do you have?
Idle mixture needle seals maybe??
bluebikerblan
Geezer
Hi Gary, I talked with Rick of OSC over the weekend re his 2mm wide x 7mm ID o-ring
he went with a standard o-ring. In Viton that would be McMaster-Carr 9263K167
I've ordered some of those and some 2mm x 8mm 9263K169 as well.
While I was at it I also ordered AS568A-109 Viton quad o-rings in a 3/32" width to snug things up a bit. 6540K133
Packs of 25 In stock for $12.26 per pack
AS568A-109
Cross Section Shape Quad
Width 3/32"
Inside Diameter 5/16"
Outside Diameter 1/2"
Material Viton® Fluoroelastomer
To bore everyone silly, I also found the M3 x.3pitch 8mm long brass phillips head screws 99658A526 at $10/hundred (brass on brass makes sense to me + crimpable)
I'm determined to replace all carb o-rings with Viton as I'm convinced that ethanol /gas swells thens dries out nitrile rubber quickly and leaves the o-ring rubber shrunk, hardened and leaking.
My
BlueOldskoolcarbs standard round 2mm x 7mm o-ring photos below....
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jfinnan
XS650 Enthusiast
I got the part number from that "boats.net" site. I then ordered the seals from the local Yamaha dealer, by having them look up one of the newer bikes listed in the "boats.net" page. They gave me a hard time about the fact that I probably had the wrong part, since their online catalog didn't list the XS. I just smiled and asked them to order four for me.
They worked great. Just remember to install them correctly. You want the "flange" part facing out. The idea being that the vacuum created by the carbs intake will suck them against the carb housing, thus sealing the shaft.
As far as my butterfly valves, I used blue loctite, then using a small chisel, I "lightly" hammered the back of the screw to flare it a bit. I'm certain they won't be coming out. Hammer force is discretionary. My carbs are tight, no leaks, so I'd say it was a success.
Oh, and mine are BS34s.
They worked great. Just remember to install them correctly. You want the "flange" part facing out. The idea being that the vacuum created by the carbs intake will suck them against the carb housing, thus sealing the shaft.
As far as my butterfly valves, I used blue loctite, then using a small chisel, I "lightly" hammered the back of the screw to flare it a bit. I'm certain they won't be coming out. Hammer force is discretionary. My carbs are tight, no leaks, so I'd say it was a success.
Oh, and mine are BS34s.
oldskoolcarbs
XS650 Addict
very nice write up blue,,,, i will agree the 2x8mm could be a better fit especially in viton
bluebikerblan
Geezer
Very interesting, I've never been able to locate a NOS part number nor source?
Could you help us out with a part number, price and source?
Is it the OEM Reference # 256-14997-00-00 that Mikes XS references?
Thanks for the help. BTW should be the same part for both BS 38 & 34. Blue
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blue............Mikesxs has the Yamaha OEM number wrong by one number. The Yamaha part number for the seals is 256-14997-00-00. I bought some from Yamaha for $3.40 per seal.
A couple of weeks ago I got some 1.9mm x 7.8mm Viton o-rings from McMaster. They were the closest I could find based on my measurements. Haven't really testing them out yet.
I did however test out some 3/32" o-rings and they were waaaaay to tight. The butterflys took like 5 seconds to fully close.
I did however test out some 3/32" o-rings and they were waaaaay to tight. The butterflys took like 5 seconds to fully close.
jfinnan
XS650 Enthusiast
BLUEBIKERBLAN.....Here is the exact link to the boats.net site:
http://www.boats.net/parts/detail/yamaha/motorcycle/Y-256-14997-00-00.html
And RETIREDGENTLEMAN had the correct part number. Those are the ones I ordered, by having them look it up for a 2005 Virago. They are not a tight fit over the shaft. And as someone else mentioned, I believe the reason is because the vacuum created on throttle is what causes them to seal. No leaks on mine, so I'm confident they are fine. Now, what will ethanol do to them? That will be a matter of time to know for sure. The old ones I removed were stiff and brittle. Certainly no way they were sealing anything.
http://www.boats.net/parts/detail/yamaha/motorcycle/Y-256-14997-00-00.html
And RETIREDGENTLEMAN had the correct part number. Those are the ones I ordered, by having them look it up for a 2005 Virago. They are not a tight fit over the shaft. And as someone else mentioned, I believe the reason is because the vacuum created on throttle is what causes them to seal. No leaks on mine, so I'm confident they are fine. Now, what will ethanol do to them? That will be a matter of time to know for sure. The old ones I removed were stiff and brittle. Certainly no way they were sealing anything.
bluebikerblan
Geezer
Thanks all for your involvement, info. and response gents...we'll get there yet. As we're finding... the "right size" in Viton replacement is not necessarily the direct size offset to a Buna-N part. Update today.... got my latest McMaster-Carr order.....You're right again Travis, the 3/32" Viton Quad seal in the 1/16" cavity was a waaaaay toooo big...(a ol' blue brainfart what was I thinking?) On the other hand the 2mm x 8mm conventional o-ring in Viton was pretty close, a little too snug perhaps? So, your "1.9mm x 7.8mm call in Viton round o-rings from McMaster" should be the nuts! Best fitting quad seal offset is still the 1/16" x 5/16" x 7/16" AS568A-011 listed by 5twins and TRG. It's is most like the OEM Buna-N Yamaha part and it's is also available in Viton for better ethanol resistance at a higher price.
All my sourcing and cost info (other than Mikes XS or Yamaha) is from McMaster-Carr.
It should be remembered that the fit and function frame of reference is the OEM Yamaha part #256-14997-00-00 Blue
All my sourcing and cost info (other than Mikes XS or Yamaha) is from McMaster-Carr.
It should be remembered that the fit and function frame of reference is the OEM Yamaha part #256-14997-00-00 Blue
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Great thread and lots of info though I'm not sure about any definitive conclusion.
I'm starting to hear a steady 'chirping' sound and am thinking it may be the throttle seals going south for the winter. Did some searching and it looks like NAPA may carry the Buna-N-Nitril in the 1/16 x 5/16 x 7/16 as part #BK 7272011. Yay?....Nay?......
I'm starting to hear a steady 'chirping' sound and am thinking it may be the throttle seals going south for the winter. Did some searching and it looks like NAPA may carry the Buna-N-Nitril in the 1/16 x 5/16 x 7/16 as part #BK 7272011. Yay?....Nay?......
