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just the tip

2K views 18 replies 5 participants last post by  Diamondj 
#1 ·
So carb #2 and #4 of the 75 cb750 started leaking fuel the other day for no good reason. I say no good reason but really I haven't been inside these carbs since the supreme court was telling Al Gore he lost the election so there was no change on my part. Pulled the bowls off (with the carbs still on the bike - thank you honda and your use of a spring clip for the bowl) and inspected everything. At first I thought it was maybe a little dirt in the needle seat but when I pulled the needle out I a little shocked. The little rubber coated tip of the needle was completely missing. The brass was still there and in good shape but the little sealing nub was nowhere in sight and the squared off tip of the needle was exposed. I have never seen this before. I managed to get #4 adjusted so it wasn't leaking by fiddling with the float height and I haven't dicked around with #2 yet but likely it can be adjusted the same until I get a replacement set of honda factory needles and seats. I have never seen this before.

I will say this though - it really pays to use your motorcycle often. I start that honda once a week (sometimes once every two weeks), whether it needs it or not (even in winter) and those carbs inside were as clean as the day I first rebuilt them way back when. fantastic.

So has anybody else seen this? normally a worn float needle usually has a grove worn in it but these didn't, just the rubber nub was missing.
 
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#2 ·
I have had to replace all of the needles on my carburated bikes for this issue.....XR400, V-Star and my GS (the GS would have been replaced anyway). It is the ethanol gas that is required to be sold. It loves to eat rubber parts. Don't store a bike for more than a month or two without draining the carbs!
 
#3 ·
I got 14 years and about 50K miles out of those needles so I really have nothing to complain about. Still the bike is starting to be like a whack a mole machine - I fix one problem and another one pops up.
 
#4 ·
cheapest price for the float needle is $16 per carb for an OEM part. What. The. Fuck. Seriously, these used to be a $5 item at best. Even the individual floats are now $27. I didn't realize honda was in such financial trouble it needed to fleece it's loyal owners of classic equipment. If I hadn't been burned by those shitty carb kits so many times I would actually consider them now. Time to hit the local bike breakers for some used needles.
 
#5 ·
I see the $15.93 is for the seat and the needle.
The gasket kit runs about $16/each too.

Few things.....

The needle and seats should not be mixed up. So going to the junk yard for just the needle is not the best idea long term. Will it work? Im sure it will, but still.

After market carb kits are shit. dont fall for it.

Personally I would just spend the $60 for 4 new needle and seat set ups and be done.
Might even spend the other $60 for new gaskets and such to know that the carbs are done for a while.

Dont not fix the bike over $60!

But since I am such a nice guy I just went into the shop and found a set of needle and seats with no rubber tip.
Think they are CB750s.

Sent you a pic

And I still have one of your racks of carbs, think CB750F 75-76
 
#6 ·
yeah I think you have the "the beast"'s old carbs. Do they have remnants of gold paint on the bodies?

Just looked at your pics and the needles struck me as funny because they have the same square tip as the ones I pulled out of #2 and #4. I am wondering if honda didn't just dip the old stock needles into some rubberizing agent and call it good. I can see the ridges on those needles in your pics - does your fingernail catch them? If so I don't think they are any good (but I still appreciate the offer), at least my old measure of when a float needle was bad was when it had worn a ridge in the thing you could feel.

I think I am going to reset the float height for #2 and see if I can cure it. I wasn't really setting by measuring for #4, I just kept bending it till it stopped leaking. One other thing I did notice that was odd was the #4 float had curled at the pivot. This had the effect of lowering the float height without changing the position of the needle tab. I am wondering of years of pushing this bike hard in the turns caused the fuel to shift in the bowl and slowly over time bend the float up. I ride too aggressively on this old junker but then again I have ridden it for so long, and through my less than stellar decision making periods in my life, it doesn't even feel aggressive until I start to hear hard parts drag, I am just too used to it. This isn't bragging, I am just trying to figure out what could have caused this as it is a new thing for me to notice.

I think I am going to pull 1&3 also and have a look at them just to make sure as soon as I fix 2 & 4 they don't start leaking as well.

I had plans to take the bike to cars and coffee this weekend so I am probably going to be figuring this out over the next couple of nights. The bike was running so good that I didn't notice it was leaking at all had a friend not mentioned to me that I was pissing dino juice while sitting at a light. Not a slow drip, but a steady stream like the bike had to relieve itself.
 
#7 ·
Sounds like it's not too hard of a fix.. Personally, I have some decent sucess with aftermarket carb kits, but I don't remember which one ( ebay )...

The thread title really threw me off though.. hahaha
was almost expecting something else if you guys know what i mean hahaha
 
#8 ·
No gold paint, but I thought that they were from the beast too.
Either way they are still here, and next round of cleanings I will do them for you.

The needles that I sent you the pictures of never had rubber tips. I never save them as they all suck.
I dont think that they are OEM though.

On a side note.....
If you had suggested that hard cornering had messed up your float setting to me in person two things would have happened.
One I would have to offer you a napkin as the beer I spit out would be all over you.
And second I would have to apologies for immediately punching you in the dick
 
#9 ·
yeah it was a little tounge in cheek. I don't think the hard cornering actually did it so much as time and heat. What would this place be if I wasn't fucking around with every post. Remember fuel is constantly pushing up on the float so it isn't unreasonable for it to move by fractions of a mm over the course of 14 years.

If they are the beast's carbs take special note of the jet sizes as they were on the yosh 811 road race motor and I would like to know at least a baseline for the jet settings. I was just going to tell you shove them in a flat rate box and ship them back but if you actually are going to clean them....who am I to stop you.
 
#10 ·
I will note the jets and such.
Unsure when the next round of cleanings will happen.
But will bet that it is before that motor needs these carbs.

Going to MidO?
If jim reads this, I will text you back letter
 
#12 ·
I seem to remember that distance stopped you before.
Well I dont think I have a wedding this year.
And the toy fund seems to be extra full so im down and should be fun.
 
#14 ·
Well I am looking forward to getting the band of misfits back together for some drunken debauchery.

Not sure of the level yet.

Egging drunks to jump off a flaming ramp at 2am?
drawing dicks on a moped?
waking buckets up in the middle of the night when he wanted to kill us, only to have him see it is us and offer us more beer?
 
#19 · (Edited)
Yup - an unfortunate schedule change for the AMA and both dates are the weekend of July 11-13. NJMP was August last year. Good event but more or less pure racing with a little bit of swap meet action. My preference is Mid-O because I'm not in need of AHRMA points from NJMP.

I know Pat's Small engine offers viton tipped float needles for Mikunis - not sure about the carbs on your CB. Any of the Honda small motor bits look similar:

Honda Carb Parts
 
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