I already did the shaft seals, and the idle started getting worse after i did it. probably coincidence. The idle still gets stuck at 3k after it warms up. its fine when i first start it but then it stays and comes down on its own. i sprayed carb cleaner and it changed the idle and brought it back down when it was stuck. I dont know what else to change. did i do something wrong? I finally found that when i spray carb cleaner here (red arrows in the pictures) it actually changes the idle, but now how do i fix it?
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I think i finally found the air leak, but how do i fix it?
- Thread starter Jawknee21
- Start date
TeeCat
One-Mik Wonder
ippytattoo
Just another grumpy old hack.
When you did the shaft seals did you do both the inboard (by the sync adjustment screw) and the outboard seals? I have never seen it myself but I have heard that sometimes the carb bodies actually wear to a point that shaft seals will not fix it.
CDNTX650
XS650 Guru
....well thats where the shaft seals if worn will pull air, they sit behind that spacer in the carb body about 1/8 inch......did you only do the outside ones? You have to remove the carbs from the bracket they are attached too, then the butterfly and remove the throttle shaft completely to access them. each carb has inner and outer. Did you even do the right seals?
CDNTX650
XS650 Guru
CDNTX650
XS650 Guru
then perhaps the bodies are ovalled bad...which means new carbs usually.
CDNTX650
XS650 Guru
well if it's leaking worse then they werent done right. what seals, correct size? I used generic Viton ones, but they were a little thin so i doubled them up so they would squich a bit more to seal.
i have the mcmaster carr website opened up in another tab right now, which happens to be conveniently located in california. haha. i did it the right way i even asked which way to put the flat side and the other side. i used the ones from mikes though. what numbers are the right ones from McMaster Carr? i cant figure it out from this post. aaaaaand, since he mentions ethanol gas how does this affect my bike? there is no gas within like 5 hours of me without ethanol. what should i buy?
"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 Blue"
"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 Blue"
CDNTX650
XS650 Guru
hmmm, well i am stumped without seeing them in person. But you know where the issue lies atleast.
I think you're on to something there.
OK, that's probably why you've got leaks now. The butterfly plate needs to be centered up in the bore before you tighten the mounting screws fully. With the mounting screws just snug and the return springs installed on the butterfly shafts, open the butterfly fully by hand and let it snap shut. Do this several times then finish tightening the mounting screws.
When you install the plates and tighten the screws before installing the return springs, this can cause the plate to bind in the bore. The spring pulls the shaft towards it slightly. That's why you need to go through the "open fully and snap shut" routine after you install the springs but while the plate mounting screws are still loose. That centers the plate for you and relieves the binding.
What's happening in your case is the butterfly plates are probably not closing fully. Most of the way, yes, but probably not 100% like they should. Since they're binding, that is pushing the shaft hard over to one side in it's pivot hole which is probably responsible for the leak. The leak combined with the plate not closing all the way is giving you the racing idle.
When you install the plates and tighten the screws before installing the return springs, this can cause the plate to bind in the bore. The spring pulls the shaft towards it slightly. That's why you need to go through the "open fully and snap shut" routine after you install the springs but while the plate mounting screws are still loose. That centers the plate for you and relieves the binding.
What's happening in your case is the butterfly plates are probably not closing fully. Most of the way, yes, but probably not 100% like they should. Since they're binding, that is pushing the shaft hard over to one side in it's pivot hole which is probably responsible for the leak. The leak combined with the plate not closing all the way is giving you the racing idle.
Oh, good thing you mentioned that. The plates won't close fully when your idle speed adjustment screw is set for 1200 (or what ever). That's how the idle speed setting works - the screw holds the butterfly plate open slightly and that determines the idle speed. When centering the plates, you need to back that idle speed adjustment screw off all the way so it's not touching the cable arm or holding the butterfly plate open at all. Back it off enough so that you can see a gap between it and the arm. Sorry, I forgot that little (but VERY important) detail, lol.
