I have tried to measure the rise or depth in this notch but I am not able to
because it is not a stepped notch but rather a ramped notch. Meaning that
the transition from the middle needle holder to the notches at the base is
gradual and I could not get my calipers to get me a reading as to it s depth
through the transition. Anything is possible but it would be hard to
position this holder on top of that ramped step and have it stay there for
long.
I wasn t inferring that you had cut your diaphragm but was adding this as an
explanation as to what has happened to those I have experienced in the past.
I guess we will have to agree to our disagreement here. As long as your
bike is performing to your expectations, that is all we can hope for.
ps. plug for my Mikuni carb kit......... No Diaphragms!
Fred
http://www.arrowheadmotorsports.com
From: RobertWichert
Sent: Thursday, April 25, 2013 10:13 AM
To: Fred Hink
Cc: klr
Subject: Re: [DSN_KLR650] CV Carb Plastic P.O.S.
Well, Fred, I beg to differ.
And, I am always ready to admit my errors... So here goes.
The diaphragm was not cut, for sure. When I put it back together the second
time everything worked great. So unless the cut healed itself (it could
happen!) it was not cut before, during or after the repairs.
The diaphragm may not have been in the groove, but I tighten everything down
gorilla-tight, so if it was not in the groove, I would have cut it badly.
I did not have a performance increase. I took the carb apart and I put it
back together wrong and the bike ran lousy. I attribute the lousy running
to having the P.O.S. blocking the slide lifting hole because when I
carefully disassembled the carburetor, the P.O.S. was not down on the
notches and it was blocking the hole. It could have moved when I
disassembled it, but I don't think so. I remember distinctly not giving a
S. where I put the P.O.S. when I installed it the first time. I just
dropped it in. I never thought about it having notches, which it has as you
correctly pointed out and I found out when I looked at it critically after I
disassembled it the second time. I then installed it correctly and the
lousy bike became normal. QED.
You are right about the needle being high if the P.O.S. is not down all the
way. So yes, it could cause problems but since the needle isn't really that
tapered, I don't see that little change as being enough to make the thing
run like a Honda 50.
What I think was happening (without X-Ray vision, I can't be sure) is that
the slide was not rising as much as it should be rising due to the
restriction in the lifting hole. But I could be wrong.
So, regardless of the reason, here is what I suggest be given as advice to
those not knowing the inner working of the CVK carburetor for putting the
CVK carburetor back together.
BE SURE TO GET THE PLASTIC NEEDLE RETAINING PIECE SEATED PROPERLY ON THE
NOTCHES IN THE SLIDE SO THE LIFTING HOLE IS NOT BLOCKED BEFORE REINSTALLING
THE SPRING. IF YOU ROTATE IT, YOU WILL SEE AND FEEL IT CLICK INTO PLACE.
I think you will agree that this is good advice, no matter what.
But as I said before, my years of experience have taught me that I can be
wrong and if so, I try to learn from my mistakes.
Robert Wichert P.Eng. LEED AP BD&C +1 916 966 9060 FAX +1 916 966 9068
=============================================== On 4/25/2013 8:51 AM, Fred
Hink wrote:
Robert,
To continue this discussion, I don t doubt you had a performance increase.
If the POS as you describe it is not down on those notches then it can t be
down on that hole. Please explain to me how you feel this plastic piece if
not indexed correctly and is on top of the indexing notches can cover that
vacuum port. Since this plastic piece if not indexed correctly is raised by
the index notches is also raised from the base of the slide where the vacuum
port is. Unless I am misunderstanding you, I don t see how this is
possible. The problem I see by not having the plastic piece indexed is that
it is not holding down the needle in the slide and could cause it to float
slightly causing a jetting issue in the midrange.
I have seen this problem (pinched diaphragms) since CVK type carbs have been
around. There is a lack of power and the slide only opens part way. Most
often there has been someone inside the carb previously (or on an old bike
it has just worn out) and has not got all of the diaphragm in the grove
where it is supposed to be. This causes a vacuum leak and the slide can not
open like it is supposed to. Most often the diaphragm is cut by tightening
the cover and may or may not work as intended after that. By making sure
that the diaphragm is in the grove it is supposed to ride in, you may have
fixed your problem. If the diaphragm edge was cut, then it may also have a
slight air leak there. Not trying to argue with you but to explain to
others that may not know the inner workings of their carburetors.
Fred
http://www.arrowheadmotorsports.com
From: RobertWichert
Sent: Thursday, April 25, 2013 9:21 AM
To: Fred Hink
Cc: klr
Subject: Re: [DSN_KLR650] CV Carb Plastic P.O.S.
That little P.O.S. did not cause any problem until I did not seat it
correctly, Fred.
And I can verify unequivocally that it CAN AND DID block the hole. I
failed to seat it in those nice little notches that I did not notice so
it was not seated correctly, by me, and it did WAY block the hole. Try
it, you won't like it.
One reason that it CAN block the hole is that the little P.O.S. has
about eight little arms, so being wrong a bit is eight times as likely
as if it had a hole for the hole, if you know what I mean.
Not to spoil the report, but I took the carburetor apart looking for the
stumble bumble and when I put it back together I did not notice that
there were notches (which I think are pretty wimpy) so I just dropped it
in. The bike ran really lousy. I took the carburetor apart and lo and
behold! The little P.O.S. was not down in the notches but was blocking
the hole! When I put it down in the notches, all was well and good.
Robert Wichert P.Eng. LEED AP BD&C
+1 916 966 9060
FAX +1 916 966 9068
===============================================
On 4/25/2013 8:02 AM, Fred Hink wrote:
> Never heard of this problem before. I have a carb on my bench and
> just took it apart to have a look. There are indexing bumps inside
> the slide near the needle holder that index the plastic keeper from
> blocking this port. I d say that there is no way that the plastic
> part can block this hole.
> You may have fixed your stumble but it most likely wasn t caused by
> this plastic piece blocking the vacuum port.
> Fred
>
http://www.arrowheadmotorsports.com
>
> *From:* RobertWichert
> *Sent:* Thursday, April 25, 2013 8:49 AM
> *To:* klr
> *Subject:* [DSN_KLR650] CV Carb Plastic P.O.S.
>
> In searching for the cure to my "Stumble Bumble" (full report to follow)
> I have discovered that deep in the CVK carburetor there is a little
> plastic P.O.S. that seems to hold the needle down on the slide by spring
> pressure from the big spring above. Interestingly enough, if you do not
> seat this little P.O.S. correctly, it can rotate "one notch" and block
> the slide lifting hole. With the slide lifting hole blocked by the
> little P.O.S., the bike doesn't go over about 3,500 RPM, and has little
> or no power.
>
> So what keeps this little P.O.S. from turning a notch when I take one of
> my famous crash and burn excursions? That spring is pretty wimpy if you
> ask me.
>
> Any insight from the carburetor guruistas?
>
> --
> Robert Wichert P.Eng. LEED AP BD&C
> +1 916 966 9060
> FAX +1 916 966 9068
>
> ===============================================
>
>
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