Topic: CB550 - Fuel not reaching the carbs

[madmtnmotors]

Don't know about the 550, but the 750's that use the rubber tipped needles have seats that cannot be replaced. I suppose a good machinist could do it, if he knew what he was doing, but well above the average "shade tree" mechanic skill (or tool) set.

Be sure to get "Viton" tipped float needles if you go aftermarket. I had cheap rubber tipped float needles (non Viton) succumb to alcohol blended fuel after just one week.

Even better (and much more expensive) are original Honda float needles, but Viton tipped needles (and bowl gaskets) are a reasonable substitute.

[Patrick]

I think Mystic is on the right track. They might be sticking because they are trashed.

[harisuluv]

Well, now that we have pictures, your problem is pretty obvious.  You have the wrong type of float valves for your carbs.  They are similar dimensions but they are not the same.  You are using 77-78 PD float valves in early carbs. 

[Joshevelle]

well _crap_

Unfortunately they are not available here in Mexico. So I'm stuck until I go to the states (one month or so). 

I bought these ones for $12.5USD:

http://www.ebay.com/itm/151790068744

I doubt they are Honda or Viton but for 12 bucks I'll use them as spares and order some Viton or Honda. Still, I have to wait till I go to the states, shipping to Mexico costs around 2 liters of blood of a virgin.

Regarding the seats, I'm thinking on ordering a complete carburetor rebuild kit from 4into1:

http://www.ebay.com/itm/181806288696

The kit contains the seats and _metal_ needles. Do you think its worth it? any other suggestion to buy from?

I would really like to have my bike running for the Distinguished Gentlemans Ride (Sep 27th), so I will hunt for those #$%^& needles/seats around town, do you guys know what bike could have the same float needles/seats??. 

Thank you all.

-Josh

[Joshevelle]

Well, now that we have pictures, your problem is pretty obvious.  You have the wrong type of float valves for your carbs.  They are similar dimensions but they are not the same.  You are using 77-78 PD float valves in early carbs.

REALLY??  do you have a link to the _actual_ parts that I would need?

Thanks a lot.

[DWS]

 i would ride for 5 miles or so and it did the same thing, then it dawned on me, it was not flowing right, Just a thought, when mine did that, i open my gas cap on the top of tank, that was it on mine, had to buy a new rubber seal and make sure it was venting, everything is good now.

[Joshevelle]

i would ride for 5 miles or so and it did the same thing, then it dawned on me, it was not flowing right, Just a thought, when mine did that, i open my gas cap on the top of tank, that was it on mine, had to buy a new rubber seal and make sure it was venting, everything is good now.

Thanks for the suggestion, I already tried the gas cap trick but did not solve the issue. 

[harisuluv]

Cb550 float valve and seat for pre 77. 72-76 cb500/cb550 is the correct part. I'm sure by now you have spent enough time with the cheapest of the eBay parts that you realize it's not worth it.

Try partsnmore.com. 

[Joshevelle]

Cb550 float valve and seat for pre 77. 72-76 cb500/cb550 is the correct part. I'm sure by now you have spent enough time with the cheapest of the eBay parts that you realize it's not worth it.

Try partsnmore.com. 

How about the 4into1 parts? would you recommend to rather buy them from partsnmore?

[Joshevelle]

My cousin is coming from CA. So I will get my needles/seats Oct 1st 

However, PartsNmore is out of stock  .

How about the 4into1 Repair Kit? the needle and seat looks the same than partsnmore:

http://4into1.com/carburetor-repair-kits-complete-set-honda-cb550k-1974-1976/

[DWS]

This is what i did, just be careful and clean well after.
0000 steal wool on a q-tip and a little oil/ or mothers brass polishing cream.
pict is from a PD 42ACB750F3

[Joshevelle]

This is what i did, just be careful and clean well after.
0000 steal wool on a q-tip and a little oil

Amazing! I will try that!!  thank you!!!

Look at your needle seat, it has an angled finish ! one of the two seats I uploaded yesterday has an angle finish, the other doesn't.

I'm definitively ordering a new set of needles/seats, but I will try to restore mines, I really like to have my bike ready for the DGR. 

[Joshevelle]

Flash from bulb

I don't think is the flash, it looks like an angled seat for the plastic cone of the float needle.

[Joshevelle]

ok. So it turns out that 4into1 has a float needle with Viton tip:

http://4into1.com/replica-keihin-float-needle-rubber-viton-tip-honda-cm200t-cb400t-cx500-cb550-cb750/

I will order 4 of those and a complete carb repair kit, just for the sake of having new needle seats too.

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), then I used the same technique that DWS mentioned (0000 steal wool on a q-tip and a little oil). I believe it is a good workaround, I just did one seat since is late night and the wife is starting to question my tasks in this house. 

I mounted the "fixed" seat into the carbs and tested it by blowing into the fuel hose and moving the floats up and down. It passed the test!  .

The one I didn't fix did _not_ pass the test. While moving the float up and down, the needle got stuck into the seat most of the time  and I couldn't blow into the fuel hose, I blowed as hard as I could (my cheeks hurt) but I couldn't unstuck it. I don't know how much pressure I could build with my longs, but I definitively  built more pressure than the fuel delivery by gravity system. Now I can perfectly understand why those carbs where completely dry.

However, tomorrow I will try make some time and """fix""" the other three. Hopefully my bike will make it to the DGR.

Saludos, and sorry for bad english.

-Josh

[harisuluv]

Well I'm going to say this again but for the last time, then you can do what  you want.  I'm not sure if it was unclear or something, but:

*Your carbs do NOT get the float valves with the VITON/rubber tips*  Those are for 77-78.  You need the earlier version.  They aren't officially compatible, and if you use them, things can happen like.. well what you're experiencing.

[madmtnmotors]

Well I'm going to say this again but for the last time, then you can do what  you want.  I'm not sure if it was unclear or something, but:

*Your carbs do NOT get the float valves with the VITON/rubber tips*  Those are for 77-78.  You need the earlier version.  They aren't officially compatible, and if you use them, things can happen like.. well what you're experiencing.

+1

harisuluv is the resident expert for all things carb related. My advice on the use of Viton tipped float needles was based upon the rubber tipped needles that were already in place without knowing that we were dealing with earlier carbs. Have we established that these are early carbs, or are these later carbs installed on an early bike?

[Joshevelle]

Well I'm going to say this again but for the last time, then you can do what  you want.  I'm not sure if it was unclear or something, but:

*Your carbs do NOT get the float valves with the VITON/rubber tips*  Those are for 77-78.  You need the earlier version.  They aren't officially compatible, and if you use them, things can happen like.. well what you're experiencing.

Ok, thanks for the clarification. Good thing is I haven't bought anything yet (except the $12 needles from ebay ). I really appreciate your inputs, since you are the expert.

I found a needle and seat for the 74 in partsnmore, it's all metal needle (see picture), they are shown as "#48-1510 | Honda CB550K (1974-1976)". BUT, it's out of stock 

How about this one? is marked for CB550K 74-76:

http://4into1.com/carburetor-repair-kits-complete-set-honda-cb550k-1974-1976/

The workaround I did is just temporal, in the hope that I can run my bike before Sep 27 (DGR). My cousin is coming Oct 1st from CA, then I can _FIX_ the carbs with the correct part numbers (hopefully).

Please, let me know if the kit from 4into1 would be the correct part for my carbs, I believe they are marked 627B.

Thanks again guys.

-Josh

[flybox1]

^^^ yay.   those will work!!!

[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? 

 

[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.

[flybox1]

tough lesson there, artistry06.   
Most modern day mechanics don't want to work on these old bikes.
There's nothing like the wisdom of this group to get you through any issue you might have.

[madmtnmotors]

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? 

 

Carburetor identification from our very own SOHC/4 website (scroll down):

http://www.sohc4.net/cb550-faq/

Looks like you have carbs from a 71-73 CB500:

[Joshevelle]

Carburetor identification from our very own SOHC/4 website (scroll down):

http://www.sohc4.net/cb550-faq/

Looks like you have carbs from a 71-73 CB500:

yep, those are for CB500. I did read that I can tune them to use them in my CB550. No problems on the tune side, so far (110 mains, #40 slow, second notch) but I need to get rid of the fuel delivery problem 

[Joshevelle]

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

[madmtnmotors]

yep, those are for CB500. I did read that I can tune them to use them in my CB550. No problems on the tune side, so far (110 mains, #40 slow, second notch) but I need to get rid of the fuel delivery problem 

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...