Topic: CB500 - can someone post pix of OEM needle vs. aftermarket needle?

[alacrity]

I got this bike and it had been "gone through" by PO.  I got a bunch of parts with it including carb internals...  and then after reading lots of info in here decided not to use the kit needles that were provided, but now I am thinking that the needles in there WERE ALSO from a kit (keyster? KL?).

There are measurements available but I don't think I can get this accurate enough to truly measure the taper correctly.  Anyone have a collection of OEM and aftermarket needles who can post pix? Or at least the OEM needle? 

I have a set that is brass colored with no markings and a set that is more of a reddish-color brass and it has a number stamped on it. 272304

Backstory in a nutshell.  Stock carbs, airbox. Uni foam filter. Mac 4-1. Kept original pistons and valves -- just re-ringed it and changed all o-rings and lapped the valves. New cam chain adjuster installed and set. all new gaskets etc.  She's oil tight.  Set the static timing meticulously. I rebuilt the carbs with all new o-rings and every orifice is spotless - including emulsion tubes. New D7ea plugs installed. Hondaman's trick ignition kit was installed a few months ago.  Love that thing.

Here's where I made a mistake:  I was running rich before - so I raised the needles one level to 3 from the top (they were at 4 before).  I am now thinking the rich running was PROBABLY due to a stuck float or some other similar prob.  So yes, mea culpa - I did that (changed too many things at once so now I have no way to track the truth - and will pay for it with more labor).

Anyway, I bench sync'd the carbs. Air screws at 1-1/8 per book spec. All back together nice and tight. All the boots and manifolds are on nice and tight. Petcock open, i see fuel come down the tygon tubes.  Couple twists of the throttle to fill the float bowls. Loosened the drain screws to be certain there was gas in all four. Check.   Battery fully charged. Choke on  - yesterday it was "freezing" here at like 65 degrees. The bike starts within 2 seconds and idles perfectly. Like a freaking sewing machine. Warms nicely.  Infrared thermometer shows 1-4 have similar temps that are a couple percent cooler than 2-3. Normal.  I blip the throttle - slowly -- But it will not take fuel after 1500-2k rpm unless I add choke (it will bog and stall with the choke on at idle -- but if I ADD CHOKE simultaneously with the throttle i can get it to climb up to 5k-6k and run.  Zoomed down the block, up through 2nd gear and I can get it to pull HARD up to 7k but I need to dump the choke at higher revs.

SO what this is telling me is: air screw is good.  Sync is good. Mainjet is good.  It's the needle that is farked. Prob TYPE of needle and position as well.  So I am gonna go back to position 4... but the question is, which needle?


thanks

[dave500]

twisting the throttle does nothing to help fill your bowls!or pump any fuel,,use the ones with numbers on them set in the middle position,i have oem and after market and youll need to measure them,,i cant pick them by eye,a photo wont really help there?what main and slow jets do you have?its not mentioned and because your po has tinkered they might be wrong?100/38 should work fine,you sure the carbs are cleaned right through?new debris from the tank hasnt reinfected them?

[haill]

if memory serves  the aftermarkets are slightly thinner at the bottom more of a straight taper where the originals have  slightly more taper starting  lower down the needle.
For sure you've not got your choke on whilst riding around for it's on when parallel to the floor.
which seems like it would be open in this position.
your float height is also very important so make sure that is correct and check it with a gauge, be very sure on this one!

[alacrity]

Petcock filter is perfect, just had the bowls off again and there is no debris whatsoever
all the jets seem to be original 100/40

The tank was purged of any debris completely, then coated with beautiful Caswell's clear epoxy.  Smoothest stuff in history.  After that was done, I filled, it, then let it flow out into my car's fuel tank, then again.  Then I filled it again to like 3/4 and shook it around for a while, then let a gallon or so flow out of the petcock into a clear plastic open container. Nary a particle.  That went into the car also. Then I removed the petcock again and the screen was clear and clean, no crappies floated out from the bottom.  New fiber washers and back on went the petcock.  Point is: the fuel is clean.

You sure about Middle position and not position 4 (counting DOWN toward the pointy end from the blunt end)?  4 is what the service manual addendum calls for.  3 is what they are set at in europe... I have the non-numbered ones installed now at setting three /

thanks

[alacrity]

yes, not just driving around with the choke on.  I described the process for working around the bad (or incorrectly positioned at slot 3) needles as a way of proving the problem - too lean through 1/4 -- 7/8 (appx) throttle.

And yes, the floats were checked and rechecked till I was beyond sick of checking.  :-)
But since I gotta pull the carbs again to change the needles anyway, wanna guess what I will check again?

[Bankerdanny]

The ones with the numbers are most likely to be Honda needles.

When I was redoing the carbs on my Goldwing I used some carb kits from Saber Cycles (which I would not recommend) and ultimately went out and found Honda needles and float needles piecemeal from various sellers at eBay to use instead

[haill]

you spoke about running rich is that on every cylinder?
this rich running was verify from pulling your plugs and reading?
take your time when you have the carbs off and give everything a good inspection cleaning and blow out passages etc with compressed air and carb cleaner make sure air is getting through etc.
make yourself a gauge which will regester off of both side of the carb body at the sametime and shows that the floats are parallel to each other and the carb body.
Made a gauge from a floppy disk drive which was easy to make but finding a floppy disk these days, ehhh maybe a old credit card etc!
22mm from the carb body to top of float when resting via gravity on fuel inlet pin.

[alacrity]

Thanks Haill. Good idea.  I would have to first build a time machine to go back and find a floppy disk holder like that...

kidding...


But the idea of making sure the floats are level/parallel/flat is good. I didn't do that the last time.

[alacrity]

here's the needle that WAS in there, at the #4 setting as shown.
(the one I prob should've left in there...).
d'oh!

[alacrity]

Thanks to all once again for the tips and advice.

Installed the apparently stock (numbered) needles set at position 4 from the blunt end... will use the kit needles as martini olive holders perhaps.

Was full-on watchmaker meticulous with the float height measurements (a couple float arms were slightly bent, so ONE side was fine and the other was off by a mm)...

Spent a couple hours rechecking/clearing every single orifice in every single jet/airway -- down to the tiniest hole...

Another 90 mins or so bench syncing using the lost-light method, as well as double-checking the heights at 4 points along the throttle's path till 1mm past the throat for full throttle (had to to best/closest average here, since they didn't stay perfectly aligned through the path -- 40 years worth of life has added just a tiny bit of slop-flex to ball/spring/arm sync system).  We're talking 1/4 -1/2mm change max between them. Final result is that I had em all really really close at any throttle position.

Installed the carbs and triple checked every single boot fitting to ensure airtightness....

Rechecked the valves.

Added fresh plugs

And triple checked the static timing.

Carb air screws at 1-1/8 per book

Ran out of things to check.

Opened the petcock. Gas flowed down the tubes. 
It didn't leak out of the carbs.

 

Tiny bit of choke.
Thumbed starter.  Engine spins 3 seconds.  Doesn't try to fire.
Power off, Opened throttle twice. bit more choke (less than half).
power on. Thumbed starter. Feathering throttle as she tries to fire.
a few engine revolutions later, she drops into a perfect idle.

Choke off after a few seconds. Idle increases. roll back throttle stop to 1100rpm.

Warm it a bit.  She takes a little throttle *unlike before!
Idle increases again, roll back throttle stop again.

Warm a bit more, a little more throttle. good quick and even response.

I am now breathing for the first time in about 90 seconds.


Quick to end of story: we went for a ride.  She's fookin' quick... first time since I first threw a leg over this thing that I wish I had more front brake!!

:-)

And that my friends is what you call a "high class problem."

I'll post sound and video (or at least links to it) later.

[haill]

Good stuff. Glad all your hard work has paid off.
Enjoy your new ride!