Topic: 1974 CB350F buildup

[aesache]

Ok so i purchased my first motorcycle today. took me 5 years to convince my wife but i finally got one. its a 1974 cb350 four which i paid $150.00 for ( i think i did pretty good)
the reason it was cheap was because i bought it as not running. i was told compression was still ok so i made a makeshift gas tank out of a 2l pop bottle but some fresh oil and gas in it and boosted it. to my amazment it ran albeit not that well actually quite poorly only ran on two cylinders but it ran. So i have a good candidate for a restoration (or at least a freshen up) i have pulled the carbs off and will be rebuilding them. but this is where i am stuck what is the best way to rebuild them they dont look that bad really and the only type of cleaner sold in my area is the spray carb cleaner but it is just not cutting it

any help would be greatly apreciated i will be posting pics of the process from start to finish i would like to completly tear down the bike and restor it to what it once was so as to have a good clean fun to ride beginner but that is RELIABLE. so if carbs is step one whats step 2?

[nickjtc]

I've never used it, but 'they' say that Yamaha Carb Cleaner is the bees knees at shifting crud from mucky carbs.

http://gallery.darladog.com/v/motorcycles/gsf400/carbcleaning/IMG_2729.JPG.html

[Bodi]

If the carbs look fairly good - the bowla are not full of crud and the inside metal in the bowls is not badly corroded - then spray cleaner should suffice for the inside passages, a pipe cleaner helps clear the emulsion air feed tube too (the brass tube sticking out toward the air cleaner side).
Remove the slow jet, float valve, slow mixture screw (if there's a plastic knob on it that will just pull off exposing the screw head) and main jet + emulsion tube. Be super careful with the float hinge pin, it's easy to snap off the support posts if you're overzealous.
The slides and needles can stay where they are if they are working freely, it's a bugger of a job to get them off and they're pretty much unserviceable... unless you need to change the needle height just leave them be. Tou should be able to persuade the main emulsion tubes to come out by pressing down with a stick on the top through the carb throat with the slide up: if not then you have to pull the slide and force it out using a wooden rod.
The emulsion tubes (one is attached to the slow jet and one is separate above the main jet) are a common clog spot, there are several tiny cross holes that need to be cleaned out but not enparged. A strand of copper from an electrical wire is good for that.
Spray cleaner through all the passages, a compressor or at least "canned air" is good to blow out and check they're not clogged. make sure the fuel crossovers and vents are open.
You can buy a set of seals from Honda, not cheap but excellent quality. You get the bowl seal, top gasket, and the O-rings for the mixture screw, float valve, and drain screw all of which you will need plus O-rings for the fuel connectors - not needed unless you take the carbs off the rack but that's a major job and not recommended unless you really need to.
That's some wicked looking exhaust! It should sound pretty wild once you get it singing on all four!
Note that the ignition work in pairs of cylinders - 1 & 4 work togather as do 2 & 3. So if one of those pairs is not working look for ignition issues.

[OakBehringer]

aesache,

Welcome to forums. Feel free to PM me anytime with any questions. I have the same year bike as you and probably have already done most things you're going to be doing in the future. I also have a growing collection of spare parts, if you need anything (you will).

Below you will find a link to an awesome pdf on tune-ups for these Honda Fours. After doing everything outlined in this pdf you will have a firm understanding of how your bike works, and you will feel like a baddass. It should also be noted that the topics covered are a must-do for any vintage bike you buy. Do them in order. First time might take you a little while, but the second time will be easy-peasy-lemon-squeesy.

Remember, carbs are last. You need to do the other stuff first.

http://www.sohc4.net/images/b/b9/Honda_4-Cylinder_Service.pdf

p.s. Getting a timing light is a small investment that will make your life infinitely easier.

Let us know if you have any questions and.. oh yea... start a thread in the project section for this!

[mattcb350f]

The emulsion tubes (one is attached to the slow jet and one is separate above the main jet) are a common clog spot, there are several tiny cross holes that need to be cleaned out but not enparged. A strand of copper from an electrical wire is good for that.

Good call Bodi, and the copper wire trick is the only thing that I could find that would fit in those holes when I cleaned my 350F carbs. I have also used a torch tip cleaner set in the past for larger jet holes but in this case, even the smallest torch tip cleaner was too large.

Be careful if you do use a torch tip cleaner as you can actually force too large of cleaner through a jet and make the jet larger....a very bad thing.


And by the way, unless that bike has been painted in the past, it's probably a 1973. All 1974 350F's were metallic black in colour while the 73's were green.

 Matt.

[flybox1]

Nice find for $150.
If all resto fails, you prob have more than that in parts.
My '73 350F was Met. Baccus Olive before the PO painted it white. 

+1 on the other stuff first.
 
Valves, points, & timing should all be done before carbs.
Follow that Duckworth article, and you're golden.

Good luck and keep us posted.

FB1

[fmctm1sw]

took me 5 years to convince my wife but i finally got one. its a 1974 cb350 four which i paid $150.00 for

Damn dude.  Took 5 years to squeeze $150 out of her?  I guess I can stop complaining!   

[ThomasTedder]

Remember, carbs are last. You need to do the other stuff first.

imho, (when dealing with any bike that has been sitting for an extended period of time) the carbs are always first.

[aesache]

WOW i cant believe the response i have had on this post the forum/you guys are great

the carbs are all clean now (i had to use some steel wool to clean the bowls but the rest was a breeze)

nickjtc- i couldnt find anyone who carried that carb cleaner in my area but i will keep looking for my next carb rebuild

Bodi- you were spot on describing the carbs and i didnt know that the ignition worked in pairs that little tid bit i am sure will save me a ton of time down the road

OakBehringer- that pdf is AMAZING i will deffinatly keep it at hand when i get this thing back together it will save me a bundle. as for needing parts the only thing i am concerned of at the moment is my bike does have 32000 miles on it so i hope the valve train doesnt show to much wear and i have been unable to find a supplier as of yet.

mattcb350f- good call on that paint color my bike manufactured in late 73 but the ownership sais 74 do you think this will be a probolem? 

flybox1 - i will take your advice. i just replaced the points on it and will be doing the valves and timing this weekend (i hope its pretty cold out)

fmctm1sw - squeezing the $150 out of her was not the problem she has a fear of motorcyles and i had (regretably) made a promise to here that i wouldnt buy a bike untill she said it was ok( when i said it i had figure it would take a week or so to convince her not 5 years) Now that she has come around i am free to start my rebuild

Oakbehringer - thats was my thinking as well i wanted to do the carbs first because 1) it came with the rebuild kits so it was free to do and also i wanted to see if the rest was worth doing before i sunk any more cash into it



thanks again guys a couple more questions my tank is rusty on the inside anyone had anyluck with the eletrolosys method? and after the tank is cleaned out do i need to line it? if so what should i use

lastly there is a spare motor for sale in my area the problem is that the guy has no idea what year it is just that the case says CBBBBB will any year 350F motor fit my bike or will i run into issues?
he wants 175 for it he sais when he bought it it was running but it has sat for 8 years does this sound like a good deal i have no idea what a spare engine is worth but some spare parts would put my mind at ease? what do you think (any of you know of anybody selling a parts bike)

thanks again guys