The NGW Project Bike. Carburetor rebuild

This Is Strictly For The "How To" Sticky's

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octane
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#16

Post by octane »

remove float bowls
Image



they most probably look something like this..eeek
..or worse
Image



remove float pivot pin
VERY VERY VERY VERY carefully.
It's not uncommon that the 'arms' that holds the pin breaks
Image
I used a sharp...er...none-screwdriver,
and tapped on it ever-so-carefully
..till I could get a grip with a set of plyers
..pulled them out in a STRAIGHT line

Remove floats.


Remove primary and secondary main jets
Image
(forgot to take picture so this is an 'installation' pic.
New o-rings and all)

Remove fuel inlet/filter screen holder
Image


have a long good look at the state they're in:
Image
The float needles-- look on the black tit--clean it with contact cleaner or carb cleaner. Use some sort of lint-less rag to dry it off. With a magnifing glass carefully inspect the black tit for any ring around the middle. If there is a ring then it should be replaced. Ideally the SEAT should also be replaced....[snip]... Also check the spring return on the other end. It should push in and out with spring tension pushing it back out. If stuck then replace the valve.
( From Ray Wooldridge )

If the screen is broken; order a new one.

If it's really messed up; order a new one.
Chuck Kichline calls them
"Your hidden enemy.
There's a tiny fuel filter behind every float valve seat.
I had one plug up and cause dropout at higher speeds
"

The inlet screen/seat/needle assembly is still available.
Part # 16011-371-305.
15-20$
Last edited by octane on Tue Aug 15, 2006 4:17 am, edited 8 times in total.
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#17

Post by Rat »

Whew .... keep up the great work.

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#18

Post by octane »

..floats.
Nothing's broken....fine
Image


Remove the small rubber-plug on top of the 'slow jet' tube.
Unscrew 'slow jet'
Image
Image







from the top (as on photo) CAREFULLY press out
secondary nozzle and primary nozzle, with a soft instrument/tool,
a piece of softish plastic or wood.
If you feel any hard resistance; soak them in your favorite brand
of penetrating oil, untill they can be pressed out without force.
Image



Look at that !!!!
secondary nozzle / slow jet / primary nozzle....aurg!
Image
at least I've found an excuse for this exercise .-)
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#19

Post by octane »

.

..gain access to the primary and secondary air jets by removing this screw
Image



using a small screwdriver,
screw out jets
Image



now for the 'slow air jets'.
Remove rubber air tube
Image

and unscrew jet.

Image
(Later US(?) models have a different kind of slow air jet
witch is not to be removed. 'Sealed' or something.
Maybe some of you can enlighten me on that)
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#20

Post by octane »

.


remove pilot screw
Image

don't forget: there's a spring down there:
Image


Please; do yourself a favor:
make some kind of system to keep your parts separated in an orderly manner!
Image
...don't throw ANYTHING away yet.

My system is: the minute I, let's say, put on a new O-ring,
I remove the old one from my plastic tray.
First of all; I have the old one for reference
and
I can keep track of witch parts has been renewed.




Now could be the time to check if everything moves freely.
This choke butterfly certainly did not.
It took two days of soaking in WD40 to free it,
(yes; WD40 does come in (non-spray) cans)
and I tell you; you don't want to use force to free a thing like that.
Image
..yeah I know; the small 'puck' is still on the carb.
More on that later.



Now as I have dismantled so far as I have, I can clean every carb
individually.
I tell you.... the exterior of those carbs just wouldn't clean up.
I tried every cleaning agent in the universe...everything!
Then it occurred to me that this brownish layer looked a lot like
varnish, lacquer or shellac or something.
So I gave them a go with paint-remover (avoiding covering the
plastic washers on the throttle axles)
...and presto! (Well not quite; it was a long process of paint remover,
detergent, paint remover etc.)
They came out rather nicely...don't you think:
Image
...then cleaned the 'interior' like two dusin times
using a healthy variation of brake cleaner, carb cleaner,
contact cleaner, lime-remover, detergents and few other things
Big brushes, small brushes, tooth brushes, stiff brushes, soft brushes
and a LOOOOOOOOOOOOT of compressed air.

Brake cleaner is really good for just general cleaning up
Contact cleaner is good for removing oxidation..that's what it's made for
Carb cleaner is good for removing fuel residue / varnish-like gum etc

But brake cleaner...ooh...love the stuff
Allways have a battery of cans ready

Image


The float bowls and plenum halves I simply 'showered' in my
bead-blasting cabinet, using the finest grade glass-media
available. I tell you; it's like the finest flour.
The surface comes out smoooooothe and nice.
(But you definitely don't need to do this,
ordinary cleaning will do nicely, thank you)
Image
.and then I washed them and blasted them with a LOT of compressed air
and then I washed them and blasted them with a LOT of compressed air
and then I washed them and blasted them with a LOT of compressed air
etc etc





I want the vacuum chamber tops
to be polished, so I removed the lacquer with paint remover.
...avoiding the plastic tops!
Image
Last edited by octane on Sun Aug 20, 2006 1:20 pm, edited 3 times in total.
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#21

Post by octane »

you'll have to remove the 'pucks' (new ones are part of Randakks brilliant rebuild kit)

If you're lucky you can do it with your air-gun


Image
inserted in the pilot screw hole



if it's reeeealy stuck, and you have no luck with WD40/contact cleaner
or similar ,(I didn't) you may have to drill into it
(careful you don't drill through it...and down into the bypass ports)

Image
..what a mess. Be anal about cleaning up.



So why do you wanna remove the puck?
Because behind that thing you'll see this:
Image
Blue arrow:
tree holes leading to the bypass ports
and you want to get in there to clean those
and the fuel ways leading to and from there.
You'll find two fuel-ways down there (besides the tree bypass ports)

and while we're there:
Yellow upper circle: underside of the pilot outlet (witch should be cleaned. No reason to remove it)
Yellow lower circle: fuel line from pilot screw, feeding the pilot outlet

and last but not least:
Red circle: pick up of vacuum from

..the (red circle) hole you seen in the next pic here
(this ONLY goes for carb 1.)
Image
(and you can see the bypass ports (blue arrow))


...the above vacuum runs through that hole
through this hole
Image

and through the upper lip of the float chamber
and down through this tube
Image
where it is picked up by the vacuum hose leading up to the air cut off valve......yep: that tiny hole a few pics back is what governs the
air cut off valve (more on that later)





...seen from the intake side:
Image
Left: small hole...vacuum uptake for air cutoff valve (only on carb 1)
Middle: tree small holes...bypass ports
Right (the 'periscope' thingie): pilot outlet




Use tons of cleaner and enormous quantities of highly compressed air
to clean all of the above
Last edited by octane on Wed Nov 01, 2006 1:40 am, edited 9 times in total.
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#22

Post by octane »

OK enough carb theory.



...another view of holes and passages to clean:
Image



..clean holes and fuel passages for primary and secondary air jets
Image



..clean holes and passage for fuel inlet
Image



..pilot screw hole
Image



..slow air jet hole
Image







..fuel inlet from plenum-body to carbs (lower hole)

..air passage from plenum witch is (upper oval hole)
a)feeding air to primary and secondary air jets
b)passage for air from plenum to float chamber
Image



You get the picture:
a hole ? a passage ? ...clean it....blow lotsa air.
Last edited by octane on Sun Aug 20, 2006 3:13 pm, edited 1 time in total.
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#23

Post by octane »

here's one set of tiny thingies you'll have removed from one carb
Image


clean, clean, clean!
I soaked them in a sort of cleaner made to clean things before it's painted
Image

and then some strong household cleaning agent
Image


..then carb cleaner and lot and lots of compressed air.
Note: these things are tiny tiny, and putting them in front of a strong
air gun makes them excellent projectiles
and you can easily spend a whole
Saturday morning trying to figure out where they landed.


Getting there:
Image


still keeping the parts for each individual carb separated
Image


Finally time to break out that brilliant set from Randakk:
Here's some of the parts
Image
(Yes I'm quite anal about keeping thing tidy and orderly;
I had a...a...sob..sob...messy childhood...my....childhood home was...so..sob...messy.........ha ho ho ; not really .-)

mmmm....well maybe a little)


Showing where which O-rings goes:
Image


Image
Third from right: primary main FUEL jet
Second from right: secondary main FUEL jet
for witch you will
NOTE:
the end with the conical hollow end
is where the O-ring goes

Here's a close up
Image

NOTE: for checking jet sizes etc.:

consult Randakks site
Last edited by octane on Sun Aug 20, 2006 2:45 pm, edited 1 time in total.
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#24

Post by octane »

fuel-bowl fuel inlet and filter/screen goes back in

Image

I did have an...er...issue with that particular O-ring from the Keyster O-ring set provided.
I couldn't really persuade the inlet/o-ring assembly into place.
Pushed really hard.
So I compared it with an OEM O-ring from a genuine Honda
fuel-inlet/screen set:
Image
...and yes; the Honda O-ring is a tiny bit thinner.
So I used that. Perfect fit. Maybe I wasn't trying hard enough....donno.


Replace retaining plate
Image
Be careful. The carbs are made of quite soft material
BUT be sure the retaining plate is fully down in position.
If not: it will influence the float height adjustment,
or rather; you'll adjust the floats/needle to a seat witch is not
in the right position height-wise.
(That's why I didn't like that O-ring; if it didn't allow the fuel inlet to
be pressed in fully)


..insert primary and secondary nozzle
Image

on later models the secondary nozzle is a two-parts thing like this
Image
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#25

Post by octane »

in goes the slow jet
Image
screw it down into position

and mount the new rubber cap supplied
Image

main jets
Image

and again: note how the hollow conical end (o-ring'ed end)goes in first




press into position
Image


install the new puck provided
Image

and new gasket provided
Image


at this point I skipped the floats etc. and put on the float chamber
and turned to the other side of the carb
as I did not want the float / needle etc. to flap about
when I did the rest of the carb.
I'll return to that in due time
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#26

Post by octane »

screw in primary and secondary air jets:
in this case 120 and 60 (check the chart for later model specs)
Image
UPPER one in the pic is the Primary (120)
LOWER one in the pis is secondary (60)

NOTE:
some if not all Clymer Manuals have got this WRONG;
they have mixed up the respective data for primary and secondary air jets!


gasket
Image


screw on retaining metal plate
Image


air pilot screw and spring
Image



slow air jet
Image
Last edited by octane on Sun Aug 20, 2006 4:35 pm, edited 1 time in total.
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#27

Post by octane »

clean vacuum chambers and pistons
Image


don't forget to clean inside here
Image

and the hole up here in the vacuum chamber cover
Image

and lotsa and lotsa compressed air.

test that they move heavenly smooooth and nice.
You may have to use the method provided in the 'Fast Lazy Furious' thread and you may have to polish them to achieve that.

One word of warning though:
the task is not only to make them move heavenly
but
to make them move heavenly without stripping chamber or piston of material, thereby creating a larger distance between the two
and lessen the units capability to hold a vacuum.
Any fool can just sand away material and in that way make them move without any friction.
Don't. You'll destroy the vacuum 'calibration'.



insert piston and the white plastic ring
Image


now: the springs: I have no idea how to check them,
but do it anyway .-)
Image


mount spring and vacuum chamber cover
Image



now that looks pretty neat...right?
Image


I choose to replace the screw with a set of SS hex. screws,
that you can find on EBay
It's a matter of preferences. I prefer these
Image



tree more to go
Image
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#28

Post by octane »

..I did come up with a rather nifty (if I may say so ) method to check the
vacuum piston springs:
Image
..put vacuum tops on a level surface
..install springs
..install piston

Measure how much each piston depress the spring.


Sure this method doesn't show if they are within spec. as I have no idea about spec.
But it will reveal if one spring is completely off.





OK let's get these carbs together:
install guide pins / fuel gasket-rubber-thingy ('rounded' end towards plenum / large O-ring

Image


IF you did split the carbs from the chrome-carb-protection thing
and into individual carbs:
..then don't forget this link:
Image

..and the small spring
Image

..and note: there should be one washer on each side
of the 'tang'-end of the throttle connecting shaft
Image


now we have something like this
Image


..mount 'net'
Four bolts
Image

..to be absolutely sure the big O-ring is properly seated,
I lifted the plenum a few mm. and put a flashlight to it,
before tightening the bolts
Image



lock the bolts
Image



.same for the two carbs / other plenum-half.
Then mount the fine new plenum rubber
and the two 'guide' pins:
lower left and upper right
Image
Last edited by octane on Thu Mar 27, 2008 1:22 pm, edited 2 times in total.
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#29

Post by octane »

..install throttle and choke mechanism.
Hopefully you haven't been as stupid as me and broken them down to individual parts...so it should be easy

anyway: considering the state they were in,
they cleaned up surprisingly nicely
Image



AAAAAAAAAAAAAAAAAAAHHH
THAT looks nice:
Image


OOOOH yes!
Image



mind you, a couple of pages back they looked like this
Image
Image



so now it's a small matter of
..installing floats, adjusting the height
..air cut off valve
..air supply hoses plenum to slow air jet
and a few other things
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#30

Post by Whiskerfish »

That is a beautiful job There Octane!!!
"Agreement is not a requirement for Respect" CDR Michael Smith USN (Ret) 2017
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Psst. oh and by the way CHANGE YOUR BELTS!!!!
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