Topic: 1974 CB550 Project: Rust Bucket 1st project for me

[brettster26]

What kind of petcock does your bike have and what did you replace it with?  My 1975, has the one with two fuel nipples and the union nut which seems to be impossible to find other than one on e-bay for $100.  Was wondering if there was another option.

[Nekneit]

I found one on ebay for a 74 for 15$. 2 nipples

[Flying J]

Try cleaning those plugs or putting in a fresh set and see if it make a difference. Those were pretty fouled looking. Also im thinking clean the connections for the coil.

I cant figure this one out. it will idle and ill adjust the carbs to sync and then when you blip the throttle, the bike either drops down in idle or starts to accelerate way up, then you have to blip the throttle to get it to come back down and the gauges are all in different places again.

I think we need to do a compression test, that is one thing we have not done yet

nobody else has any ideas for us?

[fastbroshi]

When I synced my carbs, I had the damnedest time for about 20 minutes or so.  No matter what I did, I couldn't seem to make good adjustments.  I don't have a set of carbs in front of me so this description may be crappy.   Whenever I adjusted one, it would affect them all and literally rev the bike.   Those little collars on the throttle shaft had seized ever so slightly and locked them all together.  I just loosened them, so when I adjusted one,  I could see the effect of my isolated adjustments immediately.  After I was satisfied with the sync, I locked them all down. 

This was on a 550F, '77 with the 069A carbs. 

[Flying J]

Ok, Nekneit got discouraged so i brought the bike over to my house so i could ride it and figure out what is wrong. On the way over it rode fine for a block or 2. Then at stoplights it had a high idle and would not drop.


So today i took the carbs off. I did a bench sink with a drill bit. The bike would idle fine until you revved it. The idle would stick high.

I checked the throttle cable and its not getting hung up. The only thing that brings it back down to idle right is if you press on the top of the carb throttle arms. Its almost like the slides are getting hung up and slidding up and down consistently every time. I tried shooting video to help you understand what im talking about.
Carb problems

Carb problems

[Flying J]

Well i can now say that its something messed up with the carbs. I swapped on a set off my new 550 and and the bike ran fine once it was warmed up. So Im not sure what is wrong with the carbs but they are jacked.

Who has a set of decent carbs form my friend here so we can get his bike on the road again.

[Flying J]

I robbed from my set of carbs and spent the day rebuilding them. All said and done the bike starts first try, runs and idles smooth. Problem fixed. I still cant figure out what is wrong with the old set of carbs. This new set still needs to be synced, new hoses put on it and the stupid #2 bowl is leaking.
Problem fixed

[lucky]

Well i can now say that its something messed up with the carbs. I swapped on a set off my new 550 and and the bike ran fine once it was warmed up. So Im not sure what is wrong with the carbs but they are jacked.

Who has a set of decent carbs form my friend here so we can get his bike on the road again.

You just need to take the carbs off and remove the IDLE jets and make sure you can see daylight through them. Make sure the floats are set correctly and if you did not put in NEW float needles it will never run right.
New float needles are 80% of the rebuild. Not kidding.

You cannot synch carbs until every thing else on the carbs is correct.
Syncing the carbs is like putting the name on the cake.

Float bowl is leaking or overflowing? Float needle.
If it is overflowing the float needle is not working right.

You have to put in NEW float needles. Not the seats just the needles.
If it has the all metal needles, then you will need to buy rubber tipped needles and NEW seats.

[Flying J]

Lucky, I know how to work on a bike. Did you miss the part where i said i rebuilt the carbs today. I Took them apart, flushed every hole and tube, even pressed out the emulsion tubes and put it all back together with new parts. I think it is time to find some rubber tipped needles because these metal ones are always leaking and the tank is not even dirty.

[Flying J]

Looked around and could not find these Elusive rubber tipped float needles for a CB550K.
Im pretty sure you just made them up.

[fastbroshi]

I googled "float needle cb550" and this was the first hit:

http://www.partsnmore.com/parts/honda/cb550/?filters%5Bfitting%5D=custom&filters%5Bcategory%5D=carb

[Flying J]

Yup, I just so happen to have both those needles. 1 is for a early k carb and the other is for the 77-78 carb with the rubber tip. Not interchangeable.

[fastbroshi]

So judging by his prior pics, these are the 069a type with the teardrop like top pieces you're having the problem with?

[Flying J]

Yeah they are stock for the 74. I drained the tank yesterday and filled it and then shook it around and then flushed it and blew it out. Took out a decent amount of flakes. Also cleaned the petcock and filter. Hopefully its good now. Otherwise we may have to coat the inside.