Topic: Carb issues, help.

[retro]

Hello all.  I have a '75 cb360.  So I'm in the process of starting the bike.  Done all of my adjustments, ignition, valves, oil, cleaned carbs and I tried to start bike today.  Cranks over fine, but after a couple of seconds the right side carb vent line is pissing out gas.  I removed the lower cover and checked the float and it seems to be working ok, not sticking, but I'm stumped.  I of course tried to free it up a bit more, but after reinstalling the carb its exactly the same.  This bike sat for 10 years, are there any common spots I should be going over extra careful in the carb?  Thanks for any input.

Rob

[retro]

While on the topic,  is there a set of carbs that anyone can recommend that I can upgrade to that utilize a better mechanical design, but will retain fit and function on my old bike?  Like something off an '85 or something?  I'm new to bikes and really would like to upgrade to something that would be newer, but I dont want to have to modify everything else to accomodate them.

Rob

[OldSchool_IsCool]

Is the tip of the needle valve rubberized or brass?  Sometimes a small piece of debris can get caught up between the needle and the seat holding it open.  You can knock on the carb bowl with the butt of a screw driver to see if you can free it up.  Otherwise, drop the bow, again, remove the float & needle.  Inspect the needle closely for any craption and use arisol crb cleaner to clean up the seat.  If it leaks after that, then you may need to pull the carbs out again for a more intense cleaning and possible needle/seat replacement.

[Johnie]

Did you actually remove the carbs from the bike to work on them?  The reason I ask is it will be very hard to get a good float level if they are still on the bike.

[Hush]

And while you have the carbs apart, give the pivot pin that the floats swing on a good polish up or buff with some very fine sand paper.....sometimes they will jam even though they looked OK before you put the bowl back on.
My guess is the float valve is sticking in the down position thereby letting gas flow past the float level, this can even run back into your air filter and make a real mess so best to fix this ASAP.

[retro]

I did remove the carbs, I'll try tapping the bowls to see if it frees up.  I have a feeling that I am going to convince myself to open them up again for another look.

Rob

[retro]

Hello once again.  I'll start by saying argh!!!  The bike fired up and until I let off the throttle it ran and then promptly died.  Cannot restart.  I suspected perhaps the battery being low was not allowing it to crank fast enough.  Charged battery.  Checked points and felt that right side needed a little opening up.  Now, this bike has not been started in ten years.  Once I get it running should I just lightly rock the throttle to keep it running?  I dont have the airboxes on right now and I dont have the exhaust on right now....how badly are these going to hurt the startup for me? 

Thanks in advance,
Rob

[Hush]

Your motor is gonna hate you, no airbox one side and no exhausts the other!
Your neighbours may not thing much of you either.
I'd def put the pipes on temporarily at least, flames shooting 6 feet across the garage will not give you any feeling of security.
Also all your mixtures will be crap too, pipes give you back pressure and airboxes give you mixture.
Also have you checked the carb diaphrams?
Under those nice shiny (or maybe rusty) tops you will find rubber diaphrams with the carb slides and needles attached, a hole in one of these will make tuning an impossibility.
I rebuilt 2 of these and had very little trouble with them.

[Johnie]

I did remove the carbs, I'll try tapping the bowls to see if it frees up.  I have a feeling that I am going to convince myself to open them up again for another look.

Rob

Just a thought...when you checked the float level did you turn the carbs upside down to check the level or did you place them on their side and check the level when the float and needle valve just started to make contact?

[edbikerii]

Agreed, best to be consistent with airbox and exhausts.

I'm curious whether the 1975 CB360 had CV carbs with diaphragms or just plain slide carbs like the CB550 and CB750.  I suspect mechanical slides, but I don't know for certain.

I agree with "Old School".  That fuel leaking sounds like the float valve is mucked up.  I've always been able to clean the old one, and the area around the seat, with a good carb cleaner like Berryman's B22 Chemtool, and re-use the old valve.  Remove the valve and make sure that there is no crap stuck to the rubber tip, and then use a q-tip or something, soaked in Berryman's, to clean the seat.  Be careful not to make any gouges or damage the float valve in any way.

Good luck.

Your motor is gonna hate you, no airbox one side and no exhausts the other!
Your neighbours may not thing much of you either.
I'd def put the pipes on temporarily at least, flames shooting 6 feet across the garage will not give you any feeling of security.
Also all your mixtures will be crap too, pipes give you back pressure and airboxes give you mixture.
Also have you checked the carb diaphrams?
Under those nice shiny (or maybe rusty) tops you will find rubber diaphrams with the carb slides and needles attached, a hole in one of these will make tuning an impossibility.
I rebuilt 2 of these and had very little trouble with them.

[retro]

Hello all.  Thanks for all of the responses.  I'm pretty sure that the float has freed up as it is not leaking anymore.  I will throw the exhaust on, but I have reservations about the airbox as I dont have a filter for it.  I've heard that these bikes do not like to run with a kn pod style filters on them.  Is there any truth to this?  The carb diaphrams are good with no tears. 

I've run into another snag.   It appears that the starter is seizing and has over heated and somewhat melted the solenoid beside the battery.  I thought the starter was turning over slowly, but that confirmed it so off to the wrecker I go tomorrow.  Has anyone seen that before?

Rob.

[Hush]

Does the kickstart turn the motor over easily, if the engine is trying to seize the starter motor might not be able to turn it and the heavy wiring back to the solenoid could have melted...just a thought.
But many things will melt wiring, incorrectly installing battery + to -  or - to + will do a pretty good job of turning your bike into a welding plant.
You can remove and clean up your old starter to save a few $$, usually it's just carbon dust everywhere but do check for slop at either end of the armature which will require new bushings/bearings.
You can do a visual check on the speed of the starter motor by removing it from the bike (leave main wire attached) and earth it onto the frame/motor then press start button, if it spins freely and strong your problem could be elsewhere.

Edbikerii, my CB360 had rubber diaphrams with the slides attached to them, think she was a 1975.

[OldSchool_IsCool]

Retro,

These bikes can be made to run fine on pod filters.  It takes rejetting the carb.  There is a discussion in the FAQ on what to do.