Topic: Carb Question for 1974 CB550 Build

[DJPrototypikal]

Hi all.

Rebuilding a 1974 cb550. All carbs have been rebuilt with new hardware kit. Bike only has 20K miles - and carbs seem solid.

Carb #4 keeps leaking out the overflow. Rebuilt and checked a couple of times. Still overflowing. Checked for cracks - but nothing visible.

I’ve swapped all hardware/floats between carb 3 &4 - and carb #4 keeps leaking.

I’ve stripped it down and am ultrasonic cleaning the body again, to see if that makes a difference.

If the float and needle valve are ok, how is any fuel getting in and overflowing?Thanks for any thoughts or advice.

[dave500]

the actual brass overflow pipe inside the carb may have a hair line split in it?ive seen it before,examine it closely.

[DJPrototypikal]

Thanks Old Timer

[dave500]

hey easy on the old timer comments man!im actualy a really old timer!ive repaired a couple with heat shrink over the tube,how long they last?that or do a solder repair?as i said it may or not be whats wrong,only other thing is a sinking float or the o ring around the push in valve seat is leaky?

[DJPrototypikal]

Thank you. Really appreciate the assistance. You have ‘Old Timer’ in your profile

Followup question since I am on the last steps to getting this old girl on the road…

The right and left fork covers that hold the signal lights shake and bounce a little too much - there is play between the top and resting on the plastic boot.

The original fork cushions are in rough shape - is this what keeps the covers more solid? Would building up the cushion with large o rings solve the problem?

Cheers. Niall.

[newday777]

Followup question since I am on the last steps to getting this old girl on the road…

The right and left fork covers that hold the signal lights shake and bounce a little too much - there is play between the top and resting on the plastic boot.

The original fork cushions are in rough shape - is this what keeps the covers more solid? Would building up the cushion with large o rings solve the problem?

Cheers. Niall.

Have you taken the forks apart and looked inside the fork ears yet? They could be rusted inside and the rubber rings inside could be deteriorated needing replacement.

[DJPrototypikal]

You were right about the cracked overflow tube!!

[dave500]

i repaired one once by slipping some heat shrink tube over it,solder would be better though.

[DJPrototypikal]

We soldered. Took 2 attempts but it worked a charm. I must have had that carb apart 10 times looking for the leak.

Thank you!

Yes. Forks have been apart and rebuilt. The rubber cushions are in poor shape. Going to try and use o rings as a temp fix.

[HondaMan]

Maybe check with JTMarks77 at eBay for those fork parts: he used to have some before he died. His wife[?] is running the 'store' now, so be patient while she looks, if you ask. Look up the Honda part number at places like South Sound Honda, then go to eBay and JTMarks with that number, it will help her look to see if they are there.

If not them, try NOSPARTSNOW, also at eBay. They have many OEM parts, too.

[newday777]

Maybe check with JTMarks77 at eBay for those fork parts: he used to have some before he died. His wife[?] is running the 'store' now, so be patient while she looks, if you ask. Look up the Honda part number at places like South Sound Honda, then go to eBay and JTMarks with that number, it will help her look to see if they are there.

If not them, try NOSPARTSNOW, also at eBay. They have many OEM parts, too.

Just a FYI not his wife.
His Daughter is running it now

[newday777]

We soldered. Took 2 attempts but it worked a charm. I must have had that carb apart 10 times looking for the leak.

Thank you!

Yes. Forks have been apart and rebuilt. The rubber cushions are in poor shape. Going to try and use o rings as a temp fix.

Good to hear you got the leak sealed up.

#18 top rubber 51601-323-000 David Silver has 1 in stock.
JT Mark's isn't showing any nor an ebay wide search, nor South Sound. But if you check with your local dealer and have them do a dealer search they might find someone that still has some in stock that didn't sell off their parts room.

#22 bottom rubber 51622-323-000
South Sound is showing is still available so check with them

https://www.southsoundhonda.com/--xpartsstream#/s/HOM//51622-323-000//1/y

[dave500]

good job on the solder repair!,not only the outer of the tube should be clean but if you could manage to clean the inner somehow it would flow the solder better,it wouldve sweated out old fuel and scum as soon as it got hot with the solder?