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Carb needle retainer Q

Posted: Mon Oct 24, 2011 8:59 pm
by phil x
Upon removing my carbs again to rejet (see Dyno Dissappointment thread), I decided to have another look at the slides/needles etc.

I noticed that the needle retainer can be fitted in two positions - 180 degrees apart.
looking at the plastic retainer, there are two plastic discs - a lower & an upper one, each has a chamfer/cutout 180 degrees to each other.....

If the retainer is fitted one way, the lower disc covers the hole in the bottom of the slide, fitted 180 degrees around, the hole in the slide is below the chamfer/cutout - which seems the logical orientation.
It is easier to blow/suck through the slide when the lower chamfer is above the hole too.

Mine were mixed up as I had not noticed this when I previously had the needles out.

Does this sound right, there's nothing in the Haynes or Cammos guide about it.....

Phil

Re: Carb needle retainer Q

Posted: Tue Oct 25, 2011 12:21 pm
by Neosophist
You mean the plastic with the #2 + screwdriver in it that stops the needles coming out?

I didn't think it made a difference which way you put them in, it only stops the needle moving.

Shouldn't make any differnce to blowing through the slide.. having a hard time visualising this one

Re: Carb needle retainer Q

Posted: Tue Oct 25, 2011 6:15 pm
by phil x
Neosophist wrote:You mean the plastic with the #2 + screwdriver in it that stops the needles coming out?

I didn't think it made a difference which way you put them in, it only stops the needle moving.

Shouldn't make any differnce to blowing through the slide.. having a hard time visualising this one
Yep, that's the part.
There looks to be more to the design than just to hold the needle.....
The 2 'discs' of the retainer fit snugly in the bore of the piston, almost as if the cutouts & gap between the discs act as a baffle for the hole in the bottom of the slide - hard to explain, I should have took some pics!
If fitted (what I assume is incorrectly) then the hole in the slide is blocked by the lower disc!

Just wondered what the 'right' way is to fit them effect fitting them incorrectly would be.....

Anyone have access to a genuine workshop manual to see if correct reassembly is mentioned there?

Phil

Re: Carb needle retainer Q

Posted: Wed Oct 26, 2011 1:01 pm
by Neosophist
genuine honda manual is available for download from akhara.com

all i tsays in there is turn counter clockwise while pushing lightly.

don't think they make any difference which way they go in, have mine in and out loads when messing around with jettings and needles and what not and never found that they made any odds

Re: Carb needle retainer Q

Posted: Wed Oct 26, 2011 1:45 pm
by porndoguk
i can see what he means, but again its a trial and error and only difference noticed i guess would be picked up on a dynograph

heres one i made earlier pic to explain what he means

Rick

Image

Re: Re: Carb needle retainer Q

Posted: Wed Oct 26, 2011 2:31 pm
by phil x
porndoguk wrote:i can see what he means, but again its a trial and error and only difference noticed i guess would be picked up on a dynograph

heres one i made earlier pic to explain what he means

Rick

Image
Yeah, Porndogs the man ;-)
Like I said, there does seem less resistance when the cutout on the lower disc is above the hole in the slide (when blowing through it).

It must be like it for a reason!

Phil

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Re: Carb needle retainer Q

Posted: Wed Oct 26, 2011 5:05 pm
by porndoguk
Image

Hmmmmmmmm,

based on my crappy drawings i think youll see your answer,

one will have less flow for air
one will have more flow for air,

what you need to know is if more would increase or decrese throttle responce?

Rick

Re: Carb needle retainer Q

Posted: Wed Oct 26, 2011 6:24 pm
by phil x
porndoguk wrote:Image

Hmmmmmmmm,

based on my crappy drawings i think youll see your answer,

one will have less flow for air
one will have more flow for air,

what you need to know is if more would increase or decrese throttle responce?

Rick
....well, it's suggested in Cammo's guide to drill the hole out (by .5mm?) to improve throttle response. I installed them all with the lower disc cutout above the hole :pray:

Surprised that the retainer orientation hasn't been picked up previously!

Phil

Re: Carb needle retainer Q

Posted: Thu Oct 27, 2011 11:21 am
by Neosophist
I can't see it making any difference.

I tried it earlier and the slides appear to fall at the same rate from fully compressed (timing with my crappy stopwatch)

If Honda themselves dont' specify an orientation then it isn't likely to make any difference.

Re: Carb needle retainer Q

Posted: Thu Oct 27, 2011 3:06 pm
by porndoguk
yeah i guess theoreticlly if the retainer is installed with the hole under the grooved bottom side if theres less resistance/route for the air it would give you the better responce of the two options but i would imagine the difference wouldnt be noticeable or make any difference at all.

as as Neo says if honda didnt mention it then its not worth worrying over.

Rick