Topic: ferrarcj 1980 cb650

[ferrarcj]

Ok so i pulled the air circuit for the carb on the end, I forget if its the number one or four.

There was all this white/yellow powder in it. The air valve looked good to me, no cracks or anything. So on monday im bringing the carbs all stripped apart to my work to soak them and give them a good cleaning and to check the other 3 air valves.

Hopefully they all are in great shape.

Well i ordered the boots... 70 bucks for rubber! OUCH!
But hey it needed it.
One of my old ones is still in OK condition if anyone wants one. Let Me Know.

I also have a front fender and the chain gaurd and prolly some other pieces that im not going to be using, So if anyone wants these for cheap tell me.

[ferrarcj]

O yeh

I think my accel pump isnt working the way it should.

The long metal rod that sticks out of the bowl, It seems like it should push down when throttle is applied. But i can open the carbs all the way and it just makes contact with the thing pushing it... But it dosent seem to push enough to move it?? Ill post pictures when i get these things cleaned up.

[Hush]

Those carb isolators are near on 30 years old so the new ones you are buying will last another 3 decades (makes you wanna keep the bike for your grand kids eh).
The accelerator pump can be checked by putting the #2 bowl on and filling it with gas, now just push the rod up and down a few times, I got hit in the eye with gas when I did this but it was worth it to know they worked.
If your doesn't seem to work it can only be either the spring is broken (or has been put back on the wrong side of the diaphram...don't ask long story, still makes me blush) the diaphram is torn (not much chance of that) or the carb linkage is not on square and the cam to push the rod down is not lined up right.

[ferrarcj]

Ok cool, Im thinking the carb linkage isnt on correct. Today im going to mess with the carb and the accel pump.

Boy this is turning into a can of worms lol

[manjisann]

Boy this is turning into a can of worms lol

Welcome to vintage bikes. While you're sorting it out and paying unreal amounts of money you'll ask yourself if it's worth it, but once she runs and you ride her, you'll know the answer is YES! Anyone can buy a bike from a dealership and ride it around and pay someone to maintain it, but it takes a special person to take and old bike that someone else has !@#$ed up and sort it out and get it to not only run, but run well. Keep at it, you'll get her running soon enough.

Brandon

[ferrarcj]

Ok so i got them all cleaned up, They look GREAT. The air circuit was good on all 4 of them, The accel pump was clogged but i cleaned it and it works now. So now im onto sync'ing them.

I found the bench sync page and had a few questions. When sync'ing Do i move the number 2 carb slide to about 1/8 of an inch and then make the other 3 the same?

Or do i leave the number 2 slide shut and sync the other 3 to 1/8 inch?

Im guessing i sync them all to 1/8 but am a little unclear.

[ferrarcj]

Nevermind i found what i needed

Heres a link to bench sync thats helpfull.

http://forums.sohc4.net/index.php?topic=52536.0

[Hush]

Sounds like you are getting close to solving your initial running problems and look at how much you have learned!
When the bike is running, do yourself the hugest favour and pay to get them vacuum synced by an expert, this will give better engine performance, economy and will quieten the clutch chatter most of the SOHC4's display when they are put back together after long periods off the road.
Or alternatively buy a carb sync machine and do some more learning.

One thing, in your first post your photo shows the chain side of the bike, what's your chain condition like? It just looks a bit lumpy (stuck with gunk) you can clean it by using spray cans of engine clean and then re-greasing it.
If it is an "O" ring chain (has no visible joining link and has wee rubber rings on every link) don't remove it unless you are going to replace it and use the special spray on chain grease.
If it has a standard joining link you can just unclip it and take it off for cleaning.

[manjisann]

When the bike is running, do yourself the hugest favour and pay to get them vacuum synced by an expert, this will give better engine performance, economy and will quieten the clutch chatter most of the SOHC4's display when they are put back together after long periods off the road.
Or alternatively buy a carb sync machine and do some more learning.

Since Hush is on the wrong side of the world, he has to pay a mechanic who can balance upside down on his head to do the carb sync, otherwise the fuel falls out of the carbs  But since you are in the US (ie the Right side of the world) you can balance them yourself if you get a vacuum sync tool, it's really not as hard as it initially sounds and it is amazing the difference it makes.

Brandon

[Frankenkit]

But since you are in the US (ie the Right side of the world)

oh how rarely we are really right.

[manjisann]

oh how rarely we are really right.

BUT I'M AN AMERICAN I KNOW ALL AND AM ALWAYS RIGHT!!!!!! 

Brandon

[The_Crippler]

Since Hush is on the wrong side of the world, he has to pay a mechanic who can balance upside down on his head to do the carb sync, otherwise the fuel falls out of the carbs 

Don't forget that he needs to adjust them in the reverse order and turn screws counter-clockwise.

[ferrarcj]

Ok so i got it all togather with the old cracked carb boots.


SHE RUNS!!!!


However....

I have a slight fuel leak from the brass line going from number 1 to the number 2 carb....

So im going to pull it tonight and check it out.

[Frankenkit]

sometimes the fuel line itself weeps there, too.  That bugger had me freakin' confused and PO'd for awhile.

[manjisann]

Kit's got a point, especially if you used 1/4" ID instead of metric. Metric is a very tight fit the english one is a little looser.

Brandon

[Hush]

There is a bit of movement in that brass fitting, shouldn't leak though, I thought mine was today but found it was the #2 carb leaking across to the #1 carb via the wee galley way.

[ferrarcj]

Ok well i got the carbs all figured out.

Ive got a stockpile of parts coming by tuesday, So im getting excited.

Header wrap, Clutch, gears, and springs, fork seals, paint, carb isolaters, and new grips,  just to name a few things..

Ill post some pictures of the process thus far.

I almost have the tank all preped and ready for paint.

[ferrarcj]

O yeh one more question, Is there any companys that make aftermarket gauges? Im looking for smaller ones than stock, That will bolt right up.

[The_Crippler]

No frills chrome gauges are pretty easy to google up.  I, of course, didn't bookmark any of them on this computer.  Also, JC Whitney has some nice-looking after market stuff.

[mongolianfireoil]

This thread has been helpful. I have a very similar problem with my own 80 cb650. The number 4 cylinder appears to be dead kind of. It backfires through the exhaust but the compression is in line with the other 3 cylinders. Spark is good so I know it's not electrical so I'm fairly certain I have it narrowed down to the carburator on that cylinder. It has been sitting for 25 years and I've pushed about 3 cans of carb cleaner through the carburators and 120 lbs of air pressure also. I've taken off the bowls and cleaned the jets. It is getting gas to that carburator. The only thing I haven't done other than a complete rebuild is seperated the carburators and checked the air cutoff valves. Could that be what is causing the 4th cylinder's issues?

Thank you,

[Hush]

Dead kind of is a strange term, like is Senator Kennedy dead kind of?
I wouldn't be pulling your carbs apart yet, some simple tests will help narrow your problem search.
Put a jar under your #4 drain tube and open the drain screw, do you get a decent amount of gas in the jar? is the gas full of bits and pieces?
What did the emulsion tubes (longish copper necks main jet is screwed into) look like, are the wee holes clear all the way up?
What is the mixture screw (at rear of carb and set outside the bowl) set at, is it the same as the other carbs?
Have you had the carbs synced?
Does that pipe get hot to the touch same as the others when the bike is idling?

[mongolianfireoil]

by dead kind of... with the choke pulled out, the exhaust stays cool to the touch. i know, i burned by thumb on the exhaust next to it when i checked but... when the bike starts to bog down with the choke out, you can push it in and rev it way up, it will run smooth and appear to fire for about 20 seconds and then it starts backfiring through the exhaust.

i've pulled the fast jet and it is clean all the way up. slow jets also clean. the float is close to where it needs to be, i need to bend it back down a little ways because it is leaking through the bottom right now. it wasn't leaking yesterday because i just bent the float tonight to see if it wasn't getting enough gas in the bowl. the gas is good gas with a pint of cleaner mixed in.

the mixture screw is now set at 1.5 turns out, it was set at 2.7 turns out yesterday before i adjusted the float.

i have not had the carbs synched yet. i was hoping i could leave it at the settings it was when i got it and just clean it up but i know i will need to synch them now since i've messed with that 4th carb so much this week.

on the bright side, the exhaust doesn't have a spec of rust on them.

[Frankenkit]

Make sure 1 and 4 are timed right and firing when they should.  If it's truly just 4, I would really consider if the whole slow jet passage is really, really clean.  Sometimes it can be tricky blasting all of it out.  I only say that because it smooths and runs when you have the throttle way open.

The mixture screw on our 650s is a strange animal.  It regulates the amount of mixture, but the mixture ratios stay roughly the same.  So compare it to getting a teaspoon of 30:70 fuel/air mix vs. getting a tablespoon of 30:70 fuel air mix.  My bike's pipes etc are all stock and I believe I'm 1.75 turns out (uhhh don't quote me on that) but beyond that in either direction it wouldn't idle correctly.  We could rev it way up, and get it to run, but it wouldn't idle right.

Another PITA thing to check is whether or not you cleaned and blasted out the orifices where those screws screw into. Mind the tiny spring, the wee brass washer, and the ittybitty o-ring that are all crowded in there.  They're scary easy to lose.  Don't ask how I know this.
 
Clogs and #$%* in there could be messing with otherwise great attempts at setting the carbs.

Good luck, man! Report those findings!

[mongolianfireoil]

tonight i removed the fuel mixture screw in front of the bowl and made sure i could blow through it. shot some carb cleaner in for good measure. i paid more attention to the cylinders, with the choke on, it runs almost smooth. the 1 and 3 cylinders exhaust get very hot while the 2 and 4 cylinders remained much cooler, i was able to touch the 2 and 4 cylinders about a foot away from the head for more than a second where the 1 and 3 were hot enough i couldn't. i think what i need to do is just do a bench sync on the carbs and then work from there. the number 4 cylinder still backfires through the exhaust though not as much. i did get the float back to where it needs to be. i basically bent it a little by the brass pin, held the bowl to the carb, opened the valve and watched to see if it came out the overflow. after the 3rd bend, it stopped overflowing.

I see on ebay a carb set for about 110 dollars off an 83 84 honda 650. i'm tempted to buy that for the bike since i understand them to be better carburators?

thnx for all the input.

[Hush]

If you have that much difference in the heat coming from your pipes then it is definitely a fuel mixture problem.
The one's not getting hot are running "lean" and this also explains your backfire on #4.
When you try to rev a motor and don't supply enough gas it will cough (backfire) as it attempts to do what you are asking of it.
The supply of gas to the lean cylinders is not sufficient to allow for constant even running so they don't heat like the one's getting good gas supply, hope I have explained that OK.
A really good guage of what your motor is doing is by removing all 4 plugs, yeah I know it's a PITA but gives you a real feel for what's happening inside your combustion chambers.
A good sync job should cure most of your problems unless there is a physical blockage somewhere.

Buying carbs off Ebay is like Russian roulette, you still wont know who stuffed with them or how long they have been sitting around off the bike......in saying that I have a rack of duplicate 79 carbs I use for parts and learning when my bike plays up, your call but $110 would buy a damn good carb sync from an expert.