What were you doing, working on flying carpets for the Shah?
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Carb clogged¿?
- Thread starter Noidea
- Start date
Close, but no cigar.
hmusket
CBMMA Member
Here's a link to a 650central page on diaphragm repair. 650central is owned by Michael "Mercury" Morse, who has quite a bit of respect from a lot of the members of this forum. http://www.650central.com/frepairing_a_tear_in_the_carb_dia.htm
That item was written by Farrell Hope, not by MMM. Some of his stuff is great, some needs to be taken with a grain of salt.See 2M's post, above.
2M, I don't know any rubber or plastic substance that will resist acetone, including the OE diaphragms, and I wouldn't hold that vulnerability against the Plasti-Dip; so assuming no acetone exposure, how long do reckon that fix will hold?
Remember, folks, we're talking about patching/sealing stuff that's already breaking down and will continue to break down.
2M, I don't know any rubber or plastic substance that will resist acetone, including the OE diaphragms, and I wouldn't hold that vulnerability against the Plasti-Dip; so assuming no acetone exposure, how long do reckon that fix will hold?
Remember, folks, we're talking about patching/sealing stuff that's already breaking down and will continue to break down.
...........LOL
Griz, I did the "plastidip" fix a few years before joining this forum. A few dabs with toothpick onto just the pinholes, let it cure, then masked off the slides and sprayed a thin coat to the whole bottom/atmospheric sides only. When cured, they came out smooth, glossy, worked fine.
Sometime later, I had to emergency backflush the pilot jets thru the mix screw holes. Most of that carb cleaner went thru the idle mix discharge port, into the carb throat, and I guess that the strong vapours worked their way to the diaphragms, probably by way of the crescent vent. My "plastidip" coating bubbled, became somewhat sticky, and kept the slides from lifting.
I had to dry out the diaphragms, make sure that they wouldn't stick inside the diaphragm chambers.
Then, learned of the JBMindustries diaphragms on this forum, and replaced those old, bubbled, sticky diaphragms.
That's also about when I decided to come up with a modified back-flush adapter for carb cleaners, that would block the idle mix discharge port, and prevent all that cleaner from going into the carb throat.
http://www.xs650.com/threads/revers...bs38-carburetor-pilot-circuit-idle-jet.42002/
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How long have the JBMs lasted? What do you think of them not having a cloth inner layer for strength? What brand of plastidip did you use? I'm sure I've gotten carb cleaner on factory-done "plastidip" handles without getting anything like that result.
Thanks, 2M! That adapter is pure genius.
Xjwmx, I've had those JBM diaphragms in there for maybe 3 years. So far, so good.
The cloth-backed originals are thinner, about 0.009", and more flexible.
The JBMs are about twice as thick, just a tad stiffer, and don't demonstrate enuff stretch to worry about. I was concerned about the stiffness, and thought that there may be slight lags in throttle response, but they respond just fine. Modern materials, huh? Reminds me of the old-school rope seals used in auto cranks, replaced by modern seals.
More discussions in these:
http://www.xs650.com/threads/bs-38-carb-diaphragm-replacements.999/
http://www.xs650.com/threads/carb-diaphragm-repair-replacement.44634/
This is the "Plastidip" that I used. From NAPA.
Carb cleaners have any number of variations of Toluene, Acetone, Xylene, MEK, alcohols, ...etc. Pretty aggressive stuff.
I just suspected that it was the Acetone that attacked the plastidip.
Just to be clear here. This "Plastidip" trick is NOT a fix or repair. It's a stop-gap, bandaid patch. To get you by until you can do a proper fix. Kinda like that Fix-a-Flat stuff.
As a general-purpose preventative measure, I've speared a thin layer of SylGlide (per gggGary) on the JBM diaphragms, both sides...
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Thanks. I wonder how long 4g's has lasted, or for that matter who's had them longest. Not so sure about the modern vs. old material idea, always assumed they didn't have something necessary to include the cloth layer or that it would have made them too expensive. Assumed they were prone to skimp, like not including barbs in their carb holders. And maybe bad judgment call like not making the holders to work inside the metal holders. Time'll tell...so...
"wonder how long 4g's has lasted"
I have never patched a diaphragm, not that I WOULDN'T, just never have needed too.
I have never patched a diaphragm, not that I WOULDN'T, just never have needed too.
Noidea
XS650 Addict
Heelyea that carb cleaner adapter is way neat will defiantly be putting that to use. It's been long week haven't had time to work in my bike/carbs I'm finally back at it and I noticed this the little pipe portuding on the carb is missing in my right one I assume this is a big deal but not so sure since there's nothing in the carb bible about it any answers? I also got those new diaphragms easy as heck to replace don't know how they feel when their in yet but they feel alright so far.
Attachments
75 carbs only have the pick up tube on the LH carb you are good.
There is only one choke and one of the cross over tubes carries the rich mixture to the other carb.
There is only one choke and one of the cross over tubes carries the rich mixture to the other carb.
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Wanted to be clear that I love sylglide for most things rubber, but on diaphragms I use dielectric silicon, the closest thing I can find to pure silicone with no "extenders".
Good point, gggGary.
OK, back into research mode...
OK, back into research mode...
Bob Kelly III
Ranch Kid from way back,.... that got Old !
Sick'em 2M !!!! HAHAHAH !
take more Pictures ! me likum pictures !
....
Bob..........
take more Pictures ! me likum pictures !
....
Bob..........
Bob Kelly III
Ranch Kid from way back,.... that got Old !
Ack ! we can't have that ! take a break and eat something !!!!!
HAHAHAHAHA!
Bob.......
HAHAHAHAHA!
Bob.......
