Author Topic: cb350f running issues + pics (new video on page 5)  (Read 16114 times)

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Offline fletcha221

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Re: cb350f oil fouled plugs
« Reply #25 on: January 29, 2010, 12:12:50 PM »
Davis, Any luck????
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Offline davis96

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Re: cb350f oil fouled plugs
« Reply #26 on: January 29, 2010, 04:30:16 PM »
Davis, Any luck????

I got the carbs off today, took a little longer than I'd hoped (like 45 minutes)... But no biggy, the bowl and drain screws have been soaking some liquid wrench into them for about an hour, I'm diving into them right now, I'll keep you posted on the progress.. I've got a hand full of screwdrivers, some safety wire and dental picks for cleaning passageways, a bottle of simple green, a can of carb cleaner, a can of air (didn't really feel like lugging my compressor down to school), and a heavy sense of shame that this is how I spend a Friday night.... anything I'm missing?

Cheers,
Davis
'74 CB350F - sold
'71 CB500K

Offline camelman

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Re: cb350f oil fouled plugs
« Reply #27 on: January 29, 2010, 05:03:54 PM »
The only thing you are missing are some fellow engineers to sit around with and make bad jokes about motorcycles and girls.  Take it easy on the jets if you have to clean them out.  You don't want to put a metal dental pick into them, or they'll never work right again.

Camelman
1972 350f rider: sold
1972 350f/466f cafe: for sale
1977 CB400f cafe:sold
1975 CB400f rider: sold
1970 CB750 K0 complete bike: sold
2005 Triumph Sprint ST 1050 rider

We've got to cut it off... and then come down on rockets.  (quoted from: seven minutes of terror)

Offline davis96

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Re: cb350f oil fouled plugs
« Reply #28 on: January 29, 2010, 05:06:16 PM »
Gotcha, these are just some those really small ones with the bristles and what not. I'm hoping the factory manual's diagram and my rudamentary knowledge of carburetors will suffice.
'74 CB350F - sold
'71 CB500K

Offline flybox1

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Re: cb350f oil fouled plugs
« Reply #29 on: January 29, 2010, 05:32:05 PM »
'78 750K (F3 engine) PD42b's, Modified airbox w/K&N  filter, 40/110 jets, 1 needle shim, IMS@ 1 turn out. Kerker + Cone 18" QuietCore

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Offline davis96

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Re: cb350f oil fouled plugs
« Reply #30 on: January 29, 2010, 05:54:58 PM »
alright fellas I'm officially vexed. I pulled the bowls with no issues whatsoever, and to be honest the bowls look great, only one cylinder has any trace of anything and its not the one i suspected (the cold cylinder, farthest left in the pics). I'm hoping we didnt mis-diagnos the problem here, because these look extremely clean, and all the floats move freely... is there something I should be looking for?











« Last Edit: January 29, 2010, 05:57:40 PM by davis96 »
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Offline davis96

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Re: cb350f oil fouled plugs
« Reply #31 on: January 29, 2010, 05:58:48 PM »
Davis, Any luck????
.... anything I'm missing?


girls AND beer ;)

Haha that was LAST night.. part of the reason I don't feel too bad about staying in tonight getting all loopy on gas fumes
'74 CB350F - sold
'71 CB500K

Offline davis96

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Re: cb350f oil fouled plugs
« Reply #32 on: January 29, 2010, 06:36:37 PM »
c'mon guys you gotta help me out here... what's the deal? the bowls are pretty clean and floats move freely, what could be the problem? just a reminder, heres where I was at a few days ago:

Its been running a little sluggish lately, and about a week ago, the revs would drop and the bike would die when I came to a stop (I chaulked this up to a charging issue, since my battery voltage read low--like 11.4 or something volts-- after such an annoying stop-and-go ride. Now it seems that there could be another culprit).
   It now starts just fine and idles well (a little low, but I figure I'll adjust that later with the tune up). However when I put it in gear and attempt to ride, it will die when I give it any throttle (I couldnt even rev up and ride the clutch for very far before it died). Upon researching I again thought this could be attributed to an electrical issue (regulator or rectifier) which was causing the coils not to get sufficient spark under load...when I pulled the plugs they were all fouled.

'74 CB350F - sold
'71 CB500K

Offline davis96

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Re: cb350f oil fouled plugs
« Reply #33 on: January 29, 2010, 07:38:04 PM »
you're killin me here guys, i feel like i'm doing all this cleaning in vain
'74 CB350F - sold
'71 CB500K

Offline bender01

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Re: cb350f oil fouled plugs
« Reply #34 on: January 29, 2010, 07:42:30 PM »
Youve still got to clean the carbs! the jets need to come out emulsifier tubes. They dont look clean to me. Bowls either.
75 550 K1
74 750 K4
1968 450 K1 Super Sport
74 750k 836 project
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So, the strategy is to lie to people you are asking for help?

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Good luck!
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Offline davis96

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Re: cb350f oil fouled plugs
« Reply #35 on: January 29, 2010, 07:48:40 PM »
I mean I know, that was pre-cleaning... but since there wasnt any gummed up #$%* in there and what not making the floats stick, I'm thinking that may not have been the problem... could it? I've been cleaning for a bit now, I'll show some progress pics in a few
'74 CB350F - sold
'71 CB500K

Offline davis96

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Re: cb350f oil fouled plugs
« Reply #36 on: January 29, 2010, 09:59:05 PM »
So few of my o-rings on the seals seem iffy as to if they're ok to keep using... is there anywhere where i can reliably get just some o-rings?... the bowl gaskets are fine and so are the jets themselves, so i really dont want to buy a full rebuild kit at 20 bucks per carb..

also i dont really know how to get the 'jet needle set' out of the carb... my manual sucks balls, just says "remove the jet needle set"... its down in there maybe a half-inch? i dont want to stick something down there to get it out
« Last Edit: January 29, 2010, 10:01:52 PM by davis96 »
'74 CB350F - sold
'71 CB500K

Offline HondanutRider

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Re: cb350f oil fouled plugs
« Reply #37 on: January 30, 2010, 06:33:03 AM »
Davis, the "jet needle set" as its called is also known as the "emulsifier tube".  It is a long tube with a series of small holes in it that sits under the main jet.  The needle that rises up and down with application of the throttle slides into it, letting more or less gas into the throat of the carburetor.  The gas enters from the bowl, through the main jet, into this emulsifier tube to be atomized by the small holes in it, so that it can mix with the air coming through the throat of the carburetor.  Its important that its small holes are free and clean, BUT NOT distorted or enlarged by a sharp pick in cleaning them.  Same thing for the main jet, which has one small, very accurate, hole to meter the gas flow.

To dislodge and remove the jet needle set/emulsifier, try lifting the needle by turning the throttle shaft to maximum, and then without disturbing or bending the small end of the needle - push down on the brass end of the emulsifier tube that is sticking into the throat of the carburetor.  It should move back up where the main jet sits.  Once you confirm its loose and can slide freely, you should be able to remove it from the end where the main jet resides - it just slides out.  Since that end (where the main jet rests and holds it down) is a hole without any real tolerance sensitivity, I've found I can use a small sharp screw to gently insert and jam slightly into it, allowing me to lift the tube out of the carburetor body.

One other tip!  (I speak from bad experience here.)  Be very careful when removing the pin that the float rocks on.  They often are jammed or stuck in the post holes that hold them at each end, and if you try tapping them out then then there is a possibility of breaking a post off the main body of the carburetor. :(  The pin should slide out fairly easily, just by using a little leverage with a small needle nosed pliers on one end of a post.  If they are gummed-up, then I would suggest a good soaking and also maybe a bit of careful heat from a heat gun or hair dryer.  You need to remove the float in order to remove and properly clean the float valve, which if it doesn't seal will overflow the carbs.  The body of the float valve held down with a screwed-on clamp and is also seated with another small o-ring - a different size to the one on the main jet.  You can get those o-rings but the proper ones (from Honda maybe?) are quite expensive, so you might be able to find some at an auto parts supply that would be close in size.  I've actually used some once that were close in size - they just needed a bit of careful trimming with a dremel sander.  Just use the originals, unless they are totally disintegrated and/or torn.

Offline fmctm1sw

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Re: cb350f oil fouled plugs
« Reply #38 on: January 30, 2010, 10:22:42 AM »
Its been running a little sluggish lately, and about a week ago, the revs would drop and the bike would die when I came to a stop

Mine did exactly that.  I would check two things:

1] The advance mechanism.  There should be a smooth transition starting at about 1400 rpm up to full advance.  Don't just look at the timing at idle then crank it up to 2500-3000 rpm and look at the advance marks.  That's what I was doing.

2]  Run the bike in pitch dark and watch for sparking at the plug caps.  Listen too, sometimes you can hear cracking sounds.  3 of the 4 on one of my bikes were arcing to the head.
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Dude is that a tire ? or an O-ring..??

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This is a help or GTFO thread.

1973 CB350F
1973 CB350G
1975 CB550K
1983 GL650I
1973 CB750K3 (http://forums.sohc4.net/index.php?topic=92888.0)
1984 Kawasaki KLT-250 (AKA 3 wheeler of death)
1994 Honda TRX300
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Offline davis96

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Re: cb350f oil fouled plugs
« Reply #39 on: January 30, 2010, 11:38:40 AM »
Davis, the "jet needle set" as its called is also known as the "emulsifier tube".  It is a long tube with a series of small holes in it that sits under the main jet.  The needle that rises up and down with application of the throttle slides into it, letting more or less gas into the throat of the carburetor.  The gas enters from the bowl, through the main jet, into this emulsifier tube to be atomized by the small holes in it, so that it can mix with the air coming through the throat of the carburetor.  Its important that its small holes are free and clean, BUT NOT distorted or enlarged by a sharp pick in cleaning them.  Same thing for the main jet, which has one small, very accurate, hole to meter the gas flow.

To dislodge and remove the jet needle set/emulsifier, try lifting the needle by turning the throttle shaft to maximum, and then without disturbing or bending the small end of the needle - push down on the brass end of the emulsifier tube that is sticking into the throat of the carburetor.  It should move back up where the main jet sits.  Once you confirm its loose and can slide freely, you should be able to remove it from the end where the main jet resides - it just slides out.  Since that end (where the main jet rests and holds it down) is a hole without any real tolerance sensitivity, I've found I can use a small sharp screw to gently insert and jam slightly into it, allowing me to lift the tube out of the carburetor body.

One other tip!  (I speak from bad experience here.)  Be very careful when removing the pin that the float rocks on.  They often are jammed or stuck in the post holes that hold them at each end, and if you try tapping them out then then there is a possibility of breaking a post off the main body of the carburetor. :(  The pin should slide out fairly easily, just by using a little leverage with a small needle nosed pliers on one end of a post.  If they are gummed-up, then I would suggest a good soaking and also maybe a bit of careful heat from a heat gun or hair dryer.  You need to remove the float in order to remove and properly clean the float valve, which if it doesn't seal will overflow the carbs.  The body of the float valve held down with a screwed-on clamp and is also seated with another small o-ring - a different size to the one on the main jet.  You can get those o-rings but the proper ones (from Honda maybe?) are quite expensive, so you might be able to find some at an auto parts supply that would be close in size.  I've actually used some once that were close in size - they just needed a bit of careful trimming with a dremel sander.  Just use the originals, unless they are totally disintegrated and/or torn.

Ok, yea Ive been being extra careful to not mar the brass, as it it so soft... I'm about to head to the auto parts store to see if I cant get a hold of some usable o-rings, I too would rather not deal with the stealership. The only o-ring that is broken is the #3 main jet ring.. If I replace it with an aftermarket o-ring, I think I ought to replace all the main jet rings, as I dont want to cause a better seal on one cylinder than the others. All the others seem fine, but the fit of the jets is def. not as tight as before and I'm hoping they didnt dry out a bit during cleaning... so what do you think?

With regard to the float pins, yes some of them were a real #$%* to get out.. they all came out without (thank god) breaking any of the posts. BUT, two of them are a tiny bit bent. I know that if these arent perfect, allowing full movement, then I could have all sorts of fuel issues.. I'm thinking that I cant straighten them out and give them a once over with some 400 grit, smoothing out the surface, think that will be fine? I absolutely cannot find replacement pins, apparently i'd have to buy a new float as well.

Is a bit of general tarnish on the brass jets ok? seems inevitable as uncoated brass tarnishes when exposed to water/air (both a part of the cleaning process)
'74 CB350F - sold
'71 CB500K

Offline camelman

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Re: cb350f oil fouled plugs
« Reply #40 on: January 30, 2010, 12:32:36 PM »
Sorry to hear about the broken bits... never fun.  Did you get the emulsifier tubes out?  Those are very important.  I cleaned my carbs a few times before I knew about the tubes.  After I cleaned the tubes, it was like a new bike.

Camelman
1972 350f rider: sold
1972 350f/466f cafe: for sale
1977 CB400f cafe:sold
1975 CB400f rider: sold
1970 CB750 K0 complete bike: sold
2005 Triumph Sprint ST 1050 rider

We've got to cut it off... and then come down on rockets.  (quoted from: seven minutes of terror)

Offline davis96

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Re: cb350f oil fouled plugs
« Reply #41 on: January 30, 2010, 12:53:51 PM »
I have not pulled them out yet, I've been trying to run around town while stores are still open and see what I can do about o-rings and float pivot pins... but i'll be pulling them a little later..
'74 CB350F - sold
'71 CB500K

Offline davis96

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Re: cb350f oil fouled plugs
« Reply #42 on: January 31, 2010, 01:15:15 PM »
Ok,
Everything is apart and cleaned (save the emulsion tubes, still working with 3 of them that are stuck).. and I took care of the broken O-ring..


Got these o-rings at the hardware store (if you're thinking about telling me these are going to swell up and disintegrate in the gas, save it. Keep in mind this is a $500 bike, and will be build as such since I dont have much money being a college student. If this o-ring fails, I'll replace it.)

Then I put the o-ring on the jet and clamped the jet into a power drill (with a rubber buffer around it to avoid damaging the jet itself), spun it against fine grit sandpaper, making sure to sand only the rubber, not the jet.


Side-by-side with a jet with factory o-ring, looks good to me.




fits nicely


Here's after a bit of cleaning (carb bodies are cleaner now)


after and before

So what do you guys think? Clean enough to reassemble?
'74 CB350F - sold
'71 CB500K

Offline davis96

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Re: cb350f oil fouled plugs
« Reply #43 on: January 31, 2010, 01:43:50 PM »
I need help getting these emulsion tubes out, all have been broken loose and move up and down but not very freely. I'm aprehensive to jam something down into the hole from the bowl side to pull them out. Things I've tried: 2 or 3 soakings with liquid wrench, carb cleaner, q-tip and carb cleaner straw (diameter too small to pull on the tube enough), a screw tapped ever so slightly into the hole to get some grip. any other ideas? ???
'74 CB350F - sold
'71 CB500K

Offline camelman

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Re: cb350f oil fouled plugs
« Reply #44 on: January 31, 2010, 02:36:44 PM »
I just stuck a ball-end allen wrench inside the emulsion tube and got enough purchase on it to pull it out.  If they are so dirty that they stick, then I think you have found your power robbing culprit.  Keep working on them, and be gentle.  Best to just wiggle them around until they start to pull out.

Nice job on the main jet gasket.  I have a funny feeling it won't last, but I'm curious to know how long it will last.

Camelman
1972 350f rider: sold
1972 350f/466f cafe: for sale
1977 CB400f cafe:sold
1975 CB400f rider: sold
1970 CB750 K0 complete bike: sold
2005 Triumph Sprint ST 1050 rider

We've got to cut it off... and then come down on rockets.  (quoted from: seven minutes of terror)

Offline davis96

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Re: cb350f oil fouled plugs
« Reply #45 on: January 31, 2010, 04:44:11 PM »
I finally broke down and pulled the slides/needles so I could push the emulsion tubes out from the top... well good news, one of them was completely cached with #$%*...












you bastard!


currently soaking in whats left of my carb cleaner plus a little brake cleaner



Also, I need a general idea of exactly how much tolerance there is for marring on the throat end of the emulsion tube? there are a few rreeaalllllyy tiny nicks in that end of a few of the tubes from me trying to pry them out from the top. I very lightly went over them with some 400 grit sandpaper to get the high spots down, and they look ok to me. Are they really that sensitive?
« Last Edit: January 31, 2010, 04:46:31 PM by davis96 »
'74 CB350F - sold
'71 CB500K

Offline bender01

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Re: cb350f carb cleaning issues + pics
« Reply #46 on: January 31, 2010, 05:26:58 PM »
The nicks should be fine. Those carbs were really dirty. Theyre heading the right way now. Are you doing this in your college dorm? Awesome.
75 550 K1
74 750 K4
1968 450 K1 Super Sport
74 750k 836 project
http://www.bikepics.com/members/bender01/
So, the strategy is to lie to people you are asking for help?

I think I'll be busy going for a ride.

Good luck!
Two Tired Quote !

Offline camelman

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Re: cb350f carb cleaning issues + pics
« Reply #47 on: January 31, 2010, 05:27:50 PM »
Ah, don't get too worried about it.  We just didn't want you to completely bugger them up.  Once those things are cleaned up, your bike will run like new.  Make sure to clean out the holes where the go inside the carbs too.  A paper towel and some carb cleaner should do the trick.  You want to be able to see through each hole in the tube.

Does anyone know what that buildup is from?  All of the carbs I have pulled apart have the same general color of dirt caked inside them.  I just figured it was soil that got into the old cast iron fuel tanks at gas stations (very prone to cracking, hence the nationwide fuel station tank replacements a few years ago), but I can't imagine every fuel station would have the same colored dirt.

Camelman
1972 350f rider: sold
1972 350f/466f cafe: for sale
1977 CB400f cafe:sold
1975 CB400f rider: sold
1970 CB750 K0 complete bike: sold
2005 Triumph Sprint ST 1050 rider

We've got to cut it off... and then come down on rockets.  (quoted from: seven minutes of terror)

Offline davis96

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Re: cb350f carb cleaning issues + pics
« Reply #48 on: January 31, 2010, 05:44:15 PM »
The nicks should be fine. Those carbs were really dirty. Theyre heading the right way now. Are you doing this in your college dorm? Awesome.

haha, I'll bet that'd be an upgrade. No no, I'm a senior and my parents were ready to spot paying dorm fees before I even moved into my dorm freshman year. I'm working out of one of the inumerable 40's single story houses that pepper the campus and surrounding area, the one I rent resides about 50 feet from the scenic railroad tracks; but the price is right  ;D no garage though...
'74 CB350F - sold
'71 CB500K

Offline davis96

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Re: cb350f carb cleaning issues + pics
« Reply #49 on: January 31, 2010, 06:40:52 PM »
emulsions tubes came out of the carb cleaner, and got a bit of cleaning. Some of the emulsion holes were still blocked after 30 minutes in the carb cleaner... I tried to gently get at some of them with a needle and a wire from a wire wheel, but i stopped because some still werent unblocking and i feel like some have said I could screw up the holes this way. So theyre back in a bath of 100% brake cleaner for a bit.

once i get everything back together, is there a preferred method of testing the functionality/sealing of all the systems? i know I could just put it all back together but I want to make sure nothings leaky so I dont have to install only to find problems.
'74 CB350F - sold
'71 CB500K