Topic: Continuation of carb problems...

[jmill0823]

So the rain finally stopped and I just got time to pull the carbs off my CB650.  I just plan to take them apart and clean them, then put back together.  I have read all the tutorials I could find.  None of them mentioned difficulty in taking the carbs apart once you got them off the bike.   

I cant get a single screw out of the top or bottom of the carbs.  They are all so soft that as soon as I start turning they start stripping.  I've tried using the phillips head thats made for stripped screws also, nothing will work..  Do I have to use vice grips to remove them all???  Should I get new screws? 

Next, I know this is stupid, because there are so many tutuorials, but I still am confused.  Do I just take the bottom end of the carb off and pull the jet, jet tube, pilot jet and soak them/clean them out with wire.  Do I take the round part on the top off??  I know it says to clean all the passages in the carb with spray cleaner and compressed air.  Is that just on the bottom or what?? 

I don't think I'm supposed to take the carbs apart from one another right??  And what do I need to do to measure and set the floats.   

Also, when I was removing the carbs, I had the air box bungeed back and i still didn't have clearance to get the carbs out it took using a brook stick as a pry bar, and i ended up breaking one of the pilot screws I think off of the bottom. 

I'm lost, please help me. 

[hymodyne]

Hey there,

I think an impact driver might be a sound investment to avoid further damage to screw heads. in lieu of that, I've had good success with a small pair of vice grips when applied to the sides of a screw head, but it will chew up the sides. I'm a 500 owner, so I'm not familiar with the makeup of your carbs in particular, but I'd speculate that it would be worth it to tear them all the way down for a proper cleaning. take a few pics with a digital of the carbs before and during the teardown to avoid any mistakes in the rebuild.

check threads on carb cleaning solvents to find best advice about what to soak the carb bodies and parts in before rebuild.
I scribed roman numerals I-IV on my carb bodies to avoid mixing things up. If you tear them down, you should plan to rebuild with the appropriate rebuild kit, again see the links about these for best advise. don't expect old gaskets to behave the same once you've torn the carbs down. I tried to go low budget on my first attempt at a cleaning/rebuild; only replacing o-rings, only to have to tear them down all over again once I had bought the rebuild kit; moral: there's never time to do it right, etc...

I took a piece of stiff wire and bent it to the proper length to measure the float height against the carb body (plenty of threads addressing this to help you do it right)  take the air box off; see moral above.

you're not lost, you're at the best sohc4 website on the web. Mazeltov!

hym

[jmill0823]

Ok so I got the bowls off using vice grips...i definately cant get the top of the carbs off with vice grips (if im even supposed to remove the top??)  Here are some pictures of what I have...where do I go from here??

Also what is the thing in the last picture?  The spring is rusty. 

[Cvillechopper]

Looks like you've still got the cut-off valve seat in the body (brass at the top of the picture.  These should be pulled and replace the o-ring or you'll get some rich carbs and gas flowing out the over-fill tubes many times.  You should take the main jets apart (think it's a 7 or 8 mm wrench and a screw driver) to get them cleaned right.  Pull the mixture screws out and replace the o ring or it'll be hard to adjust right.  That's all I can think of at the moment.

James

[jmill0823]

ok...is it even possible to pull out the valve seat or do i have to push it out from the top with a dowel?? 

where are the main jets on my picture??  I pulled out the only brass part sticking out which i think is the jet holder...inside of the carb body where i pulled that from is a needle looking object I'm assuming may be the main jet...do I pull it out with pliars or what? 

where are the mixture screws?? 

[Cvillechopper]

The mains are in the float bowls in your picture.  It's actually 2 parts screwed together.  The mixture screws are the grey screws still in the carb body on the bottom of the picture.  As for the valve seat, I don't profess to be good with carbs and my way may cause issues that I've not run inton yet, but I use a pair of needle nose and grab the top as best I can.  I will leave score marks that I smooth out with rolled up 400 grit sand paper.  Just don't go too far down with the pliers and score the bottom of the seat.  That's the important part.  You could send Bob Wessner an e-mail asking the best way to remove them.

[Buffo]

if you are going to take the time to remove and clean your carbs...remove every piece...every screw, o-ring, jet...everything....

especially if they need to be cleaned. if you dont totally strip and use complete rebuild kits you will just end up taking your carbs off and "cleaning" them MANY times to track down and fix other gummed up and or out of tune areas of your carbs...

use Berrymans CHEMDIP or the Yamaha carb cleaner...I like the berrymans chem dip...it comes in like a gallon paint can....BE VERY CAREFUL WITH THAT STUFF...WERE EYE PROTECTION AND PROTECT YOUR SKIN, USE IT OUT DOORS! 

 I get my carb kits/parts thru WWW.MOTORCYCLECARBS.COM they know their stuff...

do one carb at a time...I use 2 tupperwares for each carb and 2 for the misc. stuff...one for dirty parts for each and one for clean parts for each

take notes and pics if you can

replace all of the buggered screws


GO SLOW

Buffo The Magnificent

[jmill0823]

where is the pilot jet and how do I remove it?  also is it weird that all of my main jets seem to have a larger hole than people act like, and i can see straight through all of them??

[Bob Wessner]

also is it weird that all of my main jets seem to have a larger hole than people act like, and i can see straight through all of them??

It just looks that way. Remember, the needle will, at varying throttle openings, occupy a good deal of the opening your are seeing.

[jmill0823]

can somebody tell me where the pilot jet is on those carbs??  and what the thing in the last picture is with the spring and if i should replace that

sorry to be so annoying, i am lost

[Gordon]

can somebody tell me where the pilot jet is on those carbs?? 

I'm kind of wondering the same thing...

[jmill0823]

if you dont know then i am scared...does anyone know where i can find the diagrams for the carbs on a cb650c.  i found them a few weeks ago and now i cant

[Gordon]

I've never worked on 650 carbs before, but if I had to guess, I'd say the pilot jet is supposed to go in the second hole down from where the main jet goes.  Probably a press-in style, but it appears as if you don't have any.  Please don't take my wore for it, though.  Like I said, I've never worked with 650 carbs before, so maybe I'm just missing something? 

Hopefully someone who knows the 650 carbs will stop by this thread and help out.

[TwoTired]

Look in the dark hole next to where the main jet was.  Down inside should be the slow jet.  The pilot screws are the ones with the "flags" on the ends.

[jmill0823]

yeah i think i see it down in there..so how is it removed??? do i have to take the top of the carb off and push it out?

[TwoTired]

My CX carbs seem to be the same design.  The slows were removed with a flat blade screwdriver; Lefty loosey.
I used a gunsmith type, flat ground, and nearly the same width as the hole.

[bhkrause]

Ok so I got the bowls off using vice grips...i definately cant get the top of the carbs off with vice grips (if im even supposed to remove the top??)  Here are some pictures of what I have...where do I go from here??

Also what is the thing in the last picture?  The spring is rusty. 

The thing in the last picture is the air cutoff valve.  Each carb should have one, and the middle ones will be a pain to pull with out pulling the carbs apart.  If the rubber on this one is ok, I'd gamble that the others are ok too.  If it's worn and shows holes or thin spots, you'll need to replace all of them or the bike won't idle.

If you replace it, you'll get a spring with the kit.  If you don't replace it, just clean the spring up and reuse it.  Kits are available at siriusconinc for around $15.

[bhkrause]

Tops of the carbs on these shouldn't be a problem, all the passages are on the bottom.  Just check the needles to make sure that they're seated - gently push up on them, they should all stop at roughly the same height.  If you have one that seems to move all the way up into the carb top, then you'll have to pull that top off and put the needle holder back into place.  Easy to do.

Whatever you end up doing, I'd suggest running down to the local Home Depot or whatever and replacing all the screws with hex cap head screws.  Way easier to work on the carbs with an allen key, not those ridiculous "round out when you look at them" screws. 

[damn_yankee]

The last picture is the accelerator pump.

[jmill0823]

okay so the carbs have been apart for too long now. i FINALLY got the screws holding the tops off, but that didnt help.  there is no way to push the pilot jet out. its not accessible from the top.  ive run all different kinds of wire into the pilot jets and still 2 of them i cannot blow through.  i have injected berrymans into the holes that the pilot jets are pushed into.  it drains out two of them and sometimes 3 of them, but its not doing the trick..  do i need to buy a pick set and pull super hard and rip them out. 

the pilot jet is down in the hole i circled...the needle is in the other hole for the main jet, what is in the last hole??? is it just a passage?  does air have to blow through that hole as well?? 

[damn_yankee]

The hole in question is probably just a slow speed passage - but I am not 100% sure on a CB650. It is on a CB750K. A couple words of advice. Get an exploded view of your carb so you can see where the parts should go. It will really help you when you re-assemble everything.

I'd let the pilot jets soak in carb cleaner for a day and see if they open up with some compressed air. Be very gentle if you are shoving wire down into the jets as you can ruin them. I'd try and avoid having to pull them out because you'll probably have to buy new ones.

damn-yankee

[jmill0823]

well i got everything reassembled, and i think all the pilot jets are clean...got the carbs back on the bike, and it will idle around 1500-2000 on its own with the choke all the way in, but as soon as i rev it up it starts sticking at whatever rpm i rev it to...i would assume it is the floats but, if they are working properly during idle why wouldnt they work when im giving it gas...i left my float height alone because i didnt even see how to adjust it, being as the floats were all plastic, how could i bend the tang or whatever?? 

[jmill0823]

just talked to a local shop who said its not the floats, but he thinks its the needles sticking...although when i had it apart all the needles and stuff seemed good. 

they want 130 to rebuild whats there...not including parts that have to be replaced, and not including syncing it on the bike...what should i do?

[damn_yankee]

Let it warm up and take off the choke. What is the rpm?
Did you time it and check the advance?

[damn_yankee]

also make sure your throttle return cables are correct!

[jmill0823]

if i let it warm up and take off the choke, it idles at about 12-1500 rpms...sometimes it will die on me but usually its okay. 

heres something weird...all of the sudden the headlight doesnt work...all my other lights work though, and when i went to charge my battery the trouble light came on, but its a new battery.. and the battery seems fine, all other lights work...did the headlight bulb happen to go at the same time i was working on the bike or is it probable that i messed something up?

[dusterdude]

get a test lite and pull the headlite out of the housing a turn on the key switch and the headlite switch and check the plug for power.