Topic: CB550 fuel leak between carbs, common?

[j squared]

Well good news, the leaks stopped at the fuel line T's  I think it was the line actually, pretty sure I used a 1/4" line instead of 5.5mm.  But its stopped, good good.

Bad news is my #4 float seems to always to overflowing any time the gas is left on with the bike not running for a few minutes. Going to run it for a bit and see what happens, might need to pull that bowl again and take a closer look.  Thanks for the help everyone, its running nicely once again!!

[Deltarider]

Good to hear. 1/4" line is definitely to wide as Honda used ID 5,5mm for the 550F and F1 and 5,3mm for the 550F2.

Bad news is my #4 float seems to always to overflowing any time the gas is left on with the bike not running for a few minutes. Going to run it for a bit and see what happens, might need to pull that bowl again and take a closer look.

Easy to fix. First tap the float chamber with the stub end of a screw driver. When you're lucky little particle(s) between float needle and seat will fall down, leaving the set unobstructed.
If not, floatchamber #4 is the easiest to remove of them all. You can now check 'live' by pushing the floatbody from underneath if the floatneedle closes. Watch closely and make sure the needle doesn't cant. If not remove seat and needle for inspection. If damaged replace, preferably by Honda Genuine Part.

[Duanob]

1/4" line is definitely to wide as Honda used ID 5,5mm for the 550F and F1 and 5,3mm for the 550F2.

Great! I just ordered some 1/4" line and 2 filters. After researching this board the consensus was naught! The 5.5 mm was impossible to find locally or super expensive to buy. $20+ for a couple of feet of OEM? Some guys said the 1/4" worked and others say no. Guess I'll find out soon enough.

As always, you get the experience...right after you need it!

[j squared]

Well it seems to be working fine now, just make sure you have it pushed all the way on the fittings, passed both flares on the nipple and tight.  The only place it looks to be a bit too big is at the float bowl drains, where the nipple is really short and only has one flare on it.  I used a small zip-tie there to keep the line tight on the fitting.

[TwoTired]

5.5mm line fits on the nipples without the need for clamps to keep it from leaking.  1/4 inch line does need clamps.

As to expense, the 5.5mm line only needs replacing once every 25-30 years.  That doesn't seem expensive to me.


As to carb sync. 
If there was a significant valve lash change; re-sync.
If the carbs were dismounted from the stay plate; re-sync.
If the slides were removed from the carbs; re-sync.
If there is ANY chance a PO may have messed with the sync adjusters or slide actuating linkage; re-sync.
If you suspect any of the 4 cylinders may have changed it's volumetric efficiency; re-sync.

In-line filters are only used when the in tank or fuel tap filter can't be restored.  Extra filtering gains you nothing but a future maintenance chore, and almost always disrupts the gravity feed system from tank to carbs.

Cheers,

[Duanob]

Well it seems to be working fine now, just make sure you have it pushed all the way on the fittings, passed both flares on the nipple and tight.  The only place it looks to be a bit too big is at the float bowl drains, where the nipple is really short and only has one flare on it.  I used a small zip-tie there to keep the line tight on the fitting.

I used 1/8" on the drain tubes, fit nice and tight with no clamps.

TT I'll use filters until I can address the dirt and rust in my tank. That will be my winter project to clean and paint. It's not bad but I found plenty of rusty sludge on my in-tank filter tube. After cleaning the carbs I don't want that sludge in there.

As far as carb sync don't forget, if you just bought the bike and don't know the history, a carb sync is a good idea as well.

[Deltarider]

As far as carb sync don't forget, if you just bought the bike and don't know the history, a carb sync is a good idea as well.

After you checked and doublechecked about everything else and you're still not satisfied with how the engine idles, yes.
When I read about all these bikes acquired with almost virgin odometers, I find it difficult to believe the POs have done much syncing or adjusting float heights. In itself these parts won´t lose their adjustment position when the bike sits for years. If they were untouched in this respect, they´re still in the adjustment position as where they were in when the bike was handed to its first owner. And if you don't know the history of the bike, there´s a good chance the four idle adjusters and float tabs are untouched.
Warning: if you start syncing to early, that means before you´ve adressed all the other maintenance points, you will go round in circles and never reach a fine running engine. That´s my point.

[Duanob]

"When I read about all these bikes acquired with almost virgin odometers, I find it difficult to believe the POs have done much syncing or adjusting float heights"

Yeah that's understandable. I wish that was my case. I have 23K+ miles and I had a PO that fiddle farted with things he shouldn't have. In my case I won't assume anything. Also there are plenty of cases where pods and headers and all that have been installed and then the jets are messed with and so on. Frankly I can't wait to try and sync my carbs if just for the experience. Now if I only had a gauge.

BTW I just got my 1/4" fuel line and filters in today so I will let ya'll know how it fits.