Topic: CB550 - Fuel not reaching the carbs

[Joshevelle]

Correct. We're not talking about tuning, we're talking about replacement parts. This tells you that you need float needles and seats for 71-73 CB500 carbs...

OK. Partsnmore is listing the same part number for 71-73 CB500 carbs: "#48-1510 | Honda CB500K (1971-1973)".

They also show the same part number for CB550 74-76: "#48-1510 | Honda CB550K (1974-1976)"

 

Also, 4into1 has the same carburetor repair kit for CB500 71-73, than the CB550 74-76:

http://4into1.com/carburetor-repair-kits-complete-set-honda-cb500k-1971-1973/

I'm thinking on buying the whole 4into1 kit. What would you do?

[madmtnmotors]

That is correct. Honda lists the same part number for the models and years you describe (73 CB500 and 75 CB550): 16011-329-004

[flybox1]

many parts are shared between bikes. this is one of those parts.
 71-73 CB500 carbs: "#48-1510 | Honda CB500K (1971-1973)

I just finished working on my buddies '79 DOHC CB750
He'd been to two mechanics (@ $1000 each) to try to fix his plug fouling issue.
In my spare time I ran through his whole bike, did all maintenance items, and threw in a brand new set ($100) of air cutoff diaphragms (because the original 1979 ones were corroded and weren't changed by the 'trained' mechanics ) 
Cleaned and sync'd his carbs.
The bike runs like a top and doesnt foul plugs.

[DWS]

here is one sight you might like also there are many more.
http://www.motorcycleproject.com/

[Joshevelle]

many parts are shared between bikes. this is one of those parts.
 71-73 CB500 carbs: "#48-1510 | Honda CB500K (1971-1973)

I just finished working on my buddies '79 DOHC CB750
He'd been to two mechanics (@ $1000 each) to try to fix his plug fouling issue.
In my spare time I ran through his whole bike, did all maintenance items, and threw in a brand new set ($100) of air cutoff diaphragms (because the original 1979 ones were corroded and weren't changed by the 'trained' mechanics ) 
Cleaned and sync'd his carbs.
The bike runs like a top and doesnt foul plugs.

HOLLY COW !!! I bought my bike for less than 1/4 of what he paid to those pseudo mechanics. Of course it took me a year of my spare time to get it running 

I'm buying the 4into1 kit now. I will get it Oct 1st.

In the meantime, I will try my workaround 

cheers.

[DWS]

I like this guy Shane there are lots of good tips on his sight for all kinds of issues.
you don't have rubber tips but still has other tips in it.
Like one at 9:00 in (example)

[DWS]

Start at min 1:40 rest does not matter

[DWS]

Another clip that might help might help.

 

[Joshevelle]

cool! I  just subscribed to his channel, thanks!

[artistry06]

Awesome post. 

I have the same problem as well. 

For the 1st time after a few hours of riding,  went for a fuel stop,  and I noticed major leakage of fuel coming from the two carbs on the petcock side, couldn't pin point it.  Rode it home immediatly, stalled on me, had to pull over.  5-10 mins, turned it on & no leaks. 

Checked the carbs to see if they were getting fuel, and turns out that only the one carb on the side of the petcock wasn't getting any.

One of my buddies also mentioned about the float needles, wish i had known about this post before bringing it to a local mechanic. Bye bye money $$$

I'll be checking back for updates.

too bad you found it too late. Honestly I've never taken my bike to a mechanic, as flybox1 mentioned, most of the mechanics out there do not like to work with these older bikes and _honestly_ I do not trust them, I better do my own repairs so at least I know what's going on with my bike.

How much did your mechanic charge you?

This forum is my #1 information source and everybody is really helpful here. Lots of highly experience persons willing to help

-Josh

I'm very new to the bike world, about 2 months, been learning as i go when problems come up.  Lol

I'm at about $700 down the drain, with the same mechanic i brought the bike back to.  Replaced the valve gasket, rocker arm assembly, cam, retuned & cleaned the carbs. 

Had to go back because of the issue i had before.  Might be another $3-400, gonna talk him
Down on it cause they did the previous carb work.

[DWS]

Take picts and show everyone

[mystic_1]

In the meantime, I tried to fix my seats. I used a M3X0.5 tap head to "drill" the cone shaped hole where the needle plastic tip seats (see pictures)

Soooo, here's the problem with this "fix": the bevel in the needle seats must match the exact angle of the needle tips.  If they don't match, the needle won't seal properly and/or may still stick.  Your tap head looks close, maybe close enough to work, but the finish on that bevel is terrible, I'm seeing pock marks and stress fractures around the perimeter (I'm guessing you just spun it under pressure, pressure-forming the metal so to speak).  The bevel is also much larger than necessary, just comparing to this pic from upthread:



IMHO this sort of thing isn't worth screwing around with too much, the cost of just replacing the parts will be offset by the time you'll save chasing problems and experimenting.

mystic_1

[harisuluv]

Those are 77-78 carbs, pressed in, not replaceable. His are earlier replaceable type.

[DWS]

Yes sorry
78CB750F3
carbs- PD42A

Thanks again for all your help Harisuluv in the pass.

[mystic_1]

Right, I was just using that pic as an example of what the factory bevel on a float needle seat looks like.

mystic_1

[jonda500]

ok so you have a 74 bike with later style carbs (PD).  If you have pressed in seats you have PD carbs.  The rubber tipped valve is then correct.

I'm about to buy the parts from 4into1.

Just to double clarify. I do have pressed in seats, 627B carbs. Do I need or not the rubber tipped valve? 

Could we see a clear picture (not the close up one) of your 627B carbs showing these "pressed in" seats?? -these carbs normally have removable needle seats held in by a little horseshoe metal piece and a screw!
John

[Joshevelle]

ok so you have a 74 bike with later style carbs (PD).  If you have pressed in seats you have PD carbs.  The rubber tipped valve is then correct.

I'm about to buy the parts from 4into1.

Just to double clarify. I do have pressed in seats, 627B carbs. Do I need or not the rubber tipped valve? 

Could we see a clear picture (not the close up one) of your 627B carbs showing these "pressed in" seats?? -these carbs normally have removable needle seats held in by a little horseshoe metal piece and a screw!
John

I just mounted the carbs in the bike, it started fine, feels like rich but I will check that tomorrow.

The seats are exactly as you described, they are hold on by a little metal piece with a screw, I attached some pictures I took while restoring.

Regarding the bevel. You are absolutely correct, my workaround does not look at all as it looks from the factory, but it is just a temporary solution. I already bought the new pieces but I'm located in Mexico and shipping costs are absurd. So, either I wait till I go to the states (in around one month) or hopefully someone cames and bring my stuff. If I simply don't do anything I simply won't ride.

Good thing is that the bike already started and it didn't starve for fuel. I will try to ride it to see if the problem persists, hopefully I can make it to the DGR.

I will install the new seat/needle as soon as I get them.

-Josh

[Joshevelle]

In the meantime, I tried to fix my seats. I used a M3X0.5 tap head to "drill" the cone shaped hole where the needle plastic tip seats (see pictures)

Soooo, here's the problem with this "fix": the bevel in the needle seats must match the exact angle of the needle tips.  If they don't match, the needle won't seal properly and/or may still stick.  Your tap head looks close, maybe close enough to work, but the finish on that bevel is terrible, I'm seeing pock marks and stress fractures around the perimeter (I'm guessing you just spun it under pressure, pressure-forming the metal so to speak).  The bevel is also much larger than necessary, just comparing to this pic from upthread:



IMHO this sort of thing isn't worth screwing around with too much, the cost of just replacing the parts will be offset by the time you'll save chasing problems and experimenting.

mystic_1

Sorry got confused. This is intended for mystic_1:

Regarding the bevel. You are absolutely correct, my workaround does not look at all as it looks from the factory, but it is just a temporary solution. I already bought the new pieces but I'm located in Mexico and shipping costs are absurd. So, either I wait till I go to the states (in around one month) or hopefully someone cames and bring my stuff. If I simply don't do anything I simply won't ride.

Good thing is that the bike already started and it didn't starve for fuel. I will try to ride it to see if the problem persists, hopefully I can make it to the DGR.

I will install the new seat/needle as soon as I get them.

-Josh

[DWS]

You've have a little cleaning to do, don't you Josh? before you put new parts into it.
here is a quick way to check the levels in the bowls of your carbs, on or off the bike, it is not precise but gives you a visual, needs to be on its center stand or straight up, not on its side kick stand, (to level fuel in bowls).

[harisuluv]

You've have a little cleaning to do, don't you Josh? before you put new parts into it.
here is a quick way to check the levels in the bowls of your carbs, on or off the bike, it is not precise but gives you a visual, needs to be on its center stand or straight up, not on its side kick stand, (to level fuel in bowls).

Nice job!  Any particular reason you have the double return springs?  The stock one (one that you can't just take off) is usually very very ample!

[Joshevelle]

You've have a little cleaning to do, don't you Josh? before you put new parts into it.
here is a quick way to check the levels in the bowls of your carbs, on or off the bike, it is not precise but gives you a visual, needs to be on its center stand or straight up, not on its side kick stand, (to level fuel in bowls).

That picture is before I did the restoration. This is a picture of the carbs already clean.

Lucky you, you have the overflow plug that can be used as a level check too. Mines doesn't have those, I need to remove the drain plug and _fortunately_ I found a hose that fin into the threaded hole, it leaks a bit but I can measure the fuel level. I need to do it one by one b/c doing it all at the same time would drip a lot of fuel into the motor.

-Josh

[Joshevelle]

Nice job!  Any particular reason you have the double return springs?  The stock one (one that you can't just take off) is usually very very ample!

Hey harisuluv. Probably is not the right post to ask you this but, do you know what the plastic hose that is in the middle of the return spring is for? mine doesn't have one and I don't know if I need it at all.

[mystic_1]

That's just a cover for the spring, basically to keep things from getting pinched between the coils.  Not really needed. 

mystic_1

[Joshevelle]

That's just a cover for the spring, basically to keep things from getting pinched between the coils.  Not really needed. 

mystic_1

nice  . I won't bother getting one then. Thanks.

[DWS]

You've have a little cleaning to do, don't you Josh? before you put new parts into it.
here is a quick way to check the levels in the bowls of your carbs, on or off the bike, it is not precise but gives you a visual, needs to be on its center stand or straight up, not on its side kick stand, (to level fuel in bowls).

Nice job!  Any particular reason you have the double return springs?  The stock one (one that you can't just take off) is usually very very ample!

Thank you !
Yes, I put the extra spring on because it would not return all the way, when not running, the last 1/8 in was very slow, (so for safety) i think it is do to the oil rings i put on the shaft in place of the felt ones, this winter i will replace them with the felt (found them after)when i break it down again to clean the idle jets, still does not stay running till warmed up with out the choke on, so i suspect it is the slow jets that our not completely clean, as you know, they our the pressed in type and i only pulled one off them due to it was completely clogged up, the other three where spraying good (i thought at the time of bench check) , but now realize i should have pulled the other three at the same time, live and learn.