Topic: CB350F fuel lines between carbs

[gears77]

Wondering if anyone has ever tried fishing new tygon fuel lines between the carbs without taking them off the rail? Tygon is very flexible and it seems possible to fold it into place. Wishful thinking I am sure.

I really want to avoid getting into the linkages right now. The upper carbs are fine right now. I have the rail off and replacing all of the lower bits and seals and gaskets.

Any advice is appreciated.
Best wishes,
Pete

[Flyin900]

There are only brass fittings with dual O rings on the fuel rails of these carbs that extend across the bottom area between the carbs. The small sections of rubber hose your seeing between the middle area of the carb bodies are the air ports for the individual carbs. They likely can be replaced as you have suggested and they don't flow fuel, or if they do your in trouble, as that is not their purpose. If the existing ones look decent then leave them alone, as they are not a fuel distribution item and normally don't wear out unless the carbs are really rough and weathered.
The single fuel hose that supplies gas to the input brass fitting down in the fuel rail area should be able to be changed on the carbs if their off the bike no problem.

[gears77]

Brilliant Flyin.. you are 100% right. I haven't worked on one of these for ages. I was looking at the little vent hoses and they are brittle but fine. I see the fuel joints you are talking about.. they aren't leaking and I am going to leave them. The o-rings aren't part of my kits anyway.
So.. you are right and all is good. Thanks a million. I really just wanted to clean the internals and get the bike running. I wish I could ultrasonic the whole assembly without taking the slides out but I am pretty sure that would be a bad idea. Lol.

Thanks again,
Pete

[Flyin900]

Not necessarily. The fuel rails have a dual O ring seal vs later ones that only use a single O ring. If you strip the carbs down to the rack assembly. Remove float bowls and the jets removed then you can Ultrasonically clean them, I have done it many times. If your cleaner has a heat option I wouldn't use that, since the O rings are 40+ years old and the heat may not be good for them.
I can get the whole rack in my cleaner so it is much easier than a smaller ultrasonic unit. Make sure you don't use any of the brass if you bought rebuild kits from a supplier, only use the soft O ring seal parts. Reuse your original Keihin brass, since the aftermarket stuff is sketchy at best. Also pull the tops off the carbs so the ultrasonic gets into every area, then just blow everything out with compressed air to remove any remaining moisture from the slide areas.

[gears77]

Wow.. my only concern is grit on the slides.. I will just flush it really well and dry it. I take full responsibility for this!

Very interested about the new brass.. not good? But it is so shiny.. lol. Do you mean they aren't precision? They are K&L. My concern is that they o rings are already on them. You know those little things can tear on the sharp edges of the jets. I will follow your advice on that one and try to re use the OE ones.

I appreciate the expertise and advise..

I will try to give back for a second. Ultrasonic solvents.. I have tried many.. simple green, various potions, etc. Due to the metallurgy or harshness or whatever carbs always either come out chalky or super stripped dry or worst of all .. darkened.
I have tried a bunch of different heat, time, etc. I didn't want to spend the money but I bought a gallon of SharperTek SC20 carb cleaner. I mixed it as they said and so far it is the best by far! The Japanese carbs come out magically sparkling without nasty residue or chalk. I am only sharing because this has been endlessly frustrating trial and error over the years. This seems to work really well. Dillute it as they say. It doesn't take much. Oh... and don't overheat it. 115 deg max. Can't remember who was the supplier.

Thanks again!!

[gears77]

Oh, forgot... one more thing I do in the ultrasonic. I only use distilled water. It is cheap and worthwhile. Regular water can leave deposits.

[Flyin900]

Yes the jets and slide needles are not anywhere near as accurate as the OEM Keihin parts, so you risk issues with putting in the Chinese stuff. Even if it is K&L which is supposed to be Japanese it could be a risk of them not being correct. Others may have not had any issues with these aftermarket parts, yet most will advise to clean and stay with the original stuff. A little WD 40 will help you pry off the O rings on the new parts and apply then to the Keihin parts.

A case in point is I am just doing a set of CB550K carbs and the slow jet is a push in style that I bent one slightly on removal. The Honda parts fiche doesn't show this jet in their listing, yet the OEM Honda manual tells you to remove it for cleaning. I couldn't find a correct Keihin jet part, so I bought an aftermarket set of four, as that was the only way to replace it with non OEM. Upon receipt I have some very accurate needle gauges for cleaning and the spec was #42 size and the OEM are a close friction fit inside the jet, while these aftermarket are a very loose fit. They clearly are not a #42 size.
I was fortunate to find a member on here that had some OEM Keihin #42 slow jets available for sale. If I had used the aftermarket ones, likely there would have been issues with them not being a correct bore size.

[Bradleycougar]

Hello,I see you are very knowledgeable about the carbs on a CB350F.  I have had a very hard time trying to find REAL Honda  or Keihin Brass.  Do you know of a source?

I have been trying to find a carb parts explosion for the Keihin 656C that are the original carbs used on the CB350F (mine any way) Any help here?

Thank you very much,

Bradleycougar