Topic: CB550F First start after total rebuild advice needed..*pics and video added

[BomberMann650]

My bike runs fine on 627b's and with twotired's suggested needle jet.
They're functionally and physically the same.
Just swap in your jets.

[rosewood]

Bomber is your bike stock? so how exactly have you set up your 627b's? what jets, needle, air screw are using and what groove for the needle?

My bike runs fine on 627b's and with twotired's suggested needle jet.
They're functionally and physically the same.
Just swap in your jets.

[BomberMann650]

Bomber is your bike stock? so how exactly have you set up your 627b's? what jets, needle, air screw are using and what groove for the needle?

My bike runs fine on 627b's and with twotired's suggested needle jet.
They're functionally and physically the same.
Just swap in your jets.

It's a franken bike.  More stock than not.

I bought up a couple sets of 500/550 carbs on the cheap knowing that my 069A were ethanol corroded.  When I rebuilt the motor, I restored a set of carbs to go with.  The grungy lot turned out to be 627B's and were the nicest bodies I had to choose from.  They are identical castings.

Otherwise, I've got an open 4-into-1 yoshimura canister exhaust, cb650 cam with factory valve clearances per cylinder, contoured intake ports, stock airbox, and pamco timing trigger.

Iirc i'm jetted at 105/42 with the middle clip and don't remember what my ims is turned to.

[rosewood]

Cant think I can really compare my setup to yours Bomber..I'm guessing you are using the jet needles and tubes from the 627b's?

Anyway I've slowly been getting these 627b's cleaned up and back together. Have decided to run the 069a setup in them first so Im not changing too much from my last run.

Had a go at setting up the float heights on the bench. Now Ive cleaned the float needle seats inside with some polish on a q tip as was recommended and also spun the needles in a drill and just given the tips a light polish. There is a slight wear mark/ridge on them. When i checked them last night all seemed good but after letting it sit for 30mins or so 2 of the fuel levels started to rise slightly. I drained and refilled but got the same result and i cant help but think this may have been happening during my first 2 run attempts giving me a rich condition.

I have 3 sets of these float needles/seats and all of them look similar with slight wear/groove on the needle.

Has anybody had much success lapping them a bit to fix a very slow leak?

I also watched a you tube video where a guy uses a small ball bearing with a punch to 're-dress' the inside of the seat with success.

I do have a set of keyster float needles and seats but reluctant to use them just yet as i would have to adjust the tang on the float alot to set the height as they are very different in height compared to the original keihins.

Where can I purchase genuine Keihin ones from?  most seem to be keyster or replicas. CMSNL has some list but i am not 100% sure they are genuine or not..

Also if i have a very slow leak will the bike use the fuel in the bowls quick enough (especially at idle) so the fuel level stays correct while running?

[BomberMann650]

jetsrus.com

Honda Oem is available too. pn 16011-329-004
www.hondabike.com

[Deltarider]

... and also spun the needles in a drill and just given the tips a light polish.

That's a bit harsh, isn't it?

[rosewood]

Maybe??...I held them in a piece of pvc tube before tightening them up in a drill chuck. spun them and ran some cloth across the tip a few times with a dab of metal polish.

Cant see how it could be any worse than spinning a Q tip in the seat..figured i have nothing to loose but try if they aren't sealing already..

... and also spun the needles in a drill and just given the tips a light polish.

That's a bit harsh, isn't it?

[rosewood]

I had another attempt at running the bike again.

This time with the 627b carbs I rebuilt..I reused all the brass from the original 069a setup I used previously:

NOS 38 slows
NOS 100 Mains
069a emul tube
069a needles factory position second notch from top
069a air screws 1.5turns out


Spent a lot of time setting the float heights and with mix and matching the different float needle sets I had managed to get reasonably confident they are sealing well enough across all 4 now...(bench checked a few times with clear tube letting it sit for an hour or so each time.) I will look at purchasing a new set but at the moment cant justify buying original Honda ones as the shipping to NZ is crazy.

So anyway got it running again and very similar result to last time....idling seemed good but definitely rich when it sees any revs.

I'm reasonably confident I have the carb set up well now with the new bodies, and i had no fuel over flow issues this time. Also the hanging revs seem to be addressed which may be due to replacing the automotive clamps on the boots with the old factory ones.

Once it was warmed up I got a set of vac gauges I borrowed set up and surprisingly they were all very consistent across all 4. so close i didn't feel the need to try and adjust anything.

So with how it stands I feel my only options are to switch back to the 98mains and then try dropping the needle to the last position.

Failing that I think I will try the 627b needles and tubes as these are noticeably thicker towards the pointy end compared to the 069a's.

If anyone has any other suggestions please let me know?     
 
thanks for reading..

rosewood...