Topic: 1980 CB650c Rest-o by a crabby "old-timer"

[Frankenkit]

Yup, gas is getting to each of the carbs freely...  that's not the problem, I don't think.

[750goes]

Hi Kitsune,

It has to be either fuel, air, or spark.... no other choices available

What have you done/altered since you had it running roughly..

Make sure the carbs are mounted firmly and all connectors are nipped up..
make sure you are getting fuel to all carbs - if possible can you take off the bowls one at a time and check for constant, clean fuel flow and confirm.
make sure you have spark at the end of each plug and lead by individual tests..
can you check your points ?? - do you have points???

I'm sure it will be something simple.....keep at it.....

check on the operation of the choke cable/lever - is it binding or not closing/opening properly.
check your throttle cable/s for correct connection - does your bike have the return throttle cable as well ??

[Frankenkit]

TT- I'm using the choke, but I'll check to make sure it's not binding.  It seems a harder pull than it did when the bike was "new to me".

It was started once before the valve replacement/adjustment/head-gasket-replacement... I had it started once after that but the jets were clogged on 1 and 3 so I had the carbs off (again) to clean out the air passages.  Today I'm going to start with the intake manifold boots and move back.  The boots are kind of hard (think skateboard wheels-hard) and the PO had put some kind of cement all over them.  I'm wondering if the bike has a history of leaky boots and I'll need to cement them until I can replace them. (I'm dying to ride... )

Each plug has great spark.  No points. Clean fuel and a steady supply to each carb...  fuel just isn't making it to the plug somehow.

I have a feeling... a curiosity... that the plugs my friend got weren't the right kind.  I don't have the number right now, but they're not D8EA, so I'm wondering if, while the right diameter, they're too short and thus they aren't making it to the fuel to ignite it correctly?   It was a LONG day Saturday, so we'll see if that's it. I hope so.  It'd be a face-palmer, but if it ran, I wouldn't care.

[Frankenkit]

Thought I'd post a couple pics, albeit lousy low-res cell phone pics.

Took the carbs off after messing around with this and that.  Jets were clean and all, lots of fuel in the bowls, but the main body (mechanical slide, etc) was dry.  Opened up the only really available throttle pump assy. to find a big hole popped in one of the diaphragms.     Well, that would probably help prevent it from sucking 'n squirting gas where it needs to be.  Ordering all 4 from Honda, getting ready for my week-long wait.

In the meantime, I pulled the airfilter housing from a donorcycle waiting to be caféd, and replaced mine (which had been drilled full of holes to increase airflow, then duct-taped over because the airflow buggered the jetting, looked like hell, among other things...)  put my new honda bags on (original old stock hondaline bags, now 99% moss free!)  installed my heel-toe shifter (also from the donorcycle) and adjusted grips/pegs/mirrors.  Soon... soon... it will run.  Soon, she'll run out of things to throw at me and will *have* to start, right? 

[Hush]

Girl you rock, I don't know too many lady riders who could do all that (actually not too many guys either)!
Did you take the oil pan off at any stage, mine looked like the PO had been cooking tar in it and the little oil strainer thing was so blocked with varnish like substance I'm surprised my bike isn't siezed!

[Frankenkit]

Oh, I don't rock.  I'm just stubborn enough not to admit when I don't know what I'm doing, and gutsy enough to try anyway.

...and scrape enough money together to repair the resulting madness...

The fuel starvation problem has surfaced. Raven and I were looking over my carbs and realized we hadn't seen the problem because we hadn't been looking for that specifically.  The little o-rings that seal the passages between the carbs shrank to nothing with age  and I'd realized they were loose while rebuilding the carbs, but didn't realize at the time how vital that air-tightness was.  

I'm looking at my wallet and hemming and hawing wondering if I should order a couple of the $40 gasket sets (one for each carb would be ideal, but I wonder if I could 'get by' with two...) or if I could possibly get by with the carbs I have onhand from a '77 750k Supersport.  (no throttle pump but then again everything connects nice and tight, too...) I'm wondering if I can just screw in the right size jets and go?

Truth be told, getting a little frustrated.  There's not much I haven't fixed or replaced anymore:

tires (Bridgestone Spitfires)
fork seals,
shift lever, (donorcycle)
both clutch AND brake levers,(brake was busted, but both the replacement and the clutch lever went to the powdercoater...
handlebars, (orig. drag ones were too low)
grips, (Renthal)
one control pod,(lights/switches/horn)
 master cylinder, (other one sun/leak rotted)
 brake line,(SS)
New brake pads (ESB)
 air and oil filters, (Purolator)
 air cleaner, (Donorcycle)
 seat, (Rick in Oregon)
 coils (Thanks Paul!),
 starter relay,
 grab bar...
  "It's always something"... *sigh*  maybe something will work right for me soon.  God, I hope so. The bike's gonna be damn near new inside and out by the time I finish with it...

[Frankenkit]

Adjusted float heights.  By trial and error, I think I have them right now.  I overdid it the first time, carbs overflowed, motorcycle started briefly and then died again.

I'm wondering if I'm having problems with my accelerator pump (throttle pump?) it doesn't move much when I'm opening the throttle.

I realized how truly clogged the little passages are/were.  Spraying up the right lower throttle pump hole, I get a spray up the main carb body, right up the center, seemingly from whence the mechanical slide moves up/down on 1 and 2.  3 and 4 are still clogged.

Cleared the throttle pump cap (the four small passages at the bottom separated by the brass plug, their main feed, and the 2 interconnected passages) 

making slow progress, one step at a time.   

[CBJoe]

While your working on the carbs, don't forget to pull the slow jets to make sure that they're clean.

Be careful pulling them out.... Joe

[Frankenkit]

I'm having a seriously difficult time pulling them out.  I did as everyone said here and soaked their bases in WD40, then wrapped (in the case that worked) packing foam wrap around it, pulled/twisted.  Jet came out relatively easily AND was clean.  Any other attempts, I just couldn't get them out.  Any other things I should try beyond WD40? I don't want to mangle the outsides of the jets...

[Frankenkit]

Oh! I was so busy thinking about shop rags I didn't even think about leather!  Good idea!

Also, I see Z1 enterprises has Air Cut-off valve sets for half the price Honda sells them for.  The one I got off the side of my carb bank had two little slits in it, so I'm assuming it won't have the same vacuum-creating abilities it would normally.  I'd have to (probably) unrack the entire bank to get to the other three.  The throttle pump is mostly clean now, just need a little work yet. Would you recommend I replace the Air Cut-off valves, or don't you think it's entirely necessary to get a functional bike?

FWIW, I've had bad results ordering from Bike Bandit, etc, getting the wrong parts.  Does Z1 usually send the right parts?  Also, would the Air Cutoff valves keep my bike from running?  I'm figuring most of my problem starting is my idle circuit, but I want this bike to be 'right' when I'm done. I've put a lot of work in already.

I know not a lot of people have experience with the 650 mechanical slide carbs (the last post on this topic was kind of inconclusive and from 2006) but I was wondering if anyone had any more info now?

[Frankenkit]

It is making sense.  it's an '80 650, or "PD50B" carbs.  These valves are on the on the side of each carb, the diaphragm looking like this
under the cap.

Frankly, I'm kind of puzzled.  Honda parts fiche lists them as the 'air cut-off valve' but Clymer doesn't mention them at all. 

[Frankenkit]

Sure.

Due to a recent computer crash, I don't have my usu. image editing program, so please bear with me... These pics are from this summer when I had the choke plates off.

Boxed in in black are the covers for the air cutoff diaphragms, in red is a spring with an adjustment stud and locknut that, as far as I can see, doesn't actually adjust anything.    Didn't touch it when I rebuilt the carbs, didn't see anything it attached to then, either (but when I got the bike, the PO said the carbs had just been rebuilt by someone else, so there have clearly been too many hands on these things...

[Frankenkit]

I do have a throttle pump off #2.  I hadn't realized how clogged it was until just the other day. Still cleaning it out.  I think your suspicion about the third passage is right- I think it does go to the air cutoff...

going into the shop today, will try to come home with sufficient pictures.

[Frankenkit]

Today, unracked carbs and thoroughly sprayed out all the little passages.  Checked all the diaphragms, reracked.  only problem right now is that the choke seems to want to bind, so working on that.    I'd had enough for the day, though, and hung it up.  Next work day is either Wednesday or Saturday.  Midterms tomorrow mean studying tonight 

[BlindJoe]

I had the same problem with the choke binding, I  unscrewed a couple of the butterflys a little bit and it moved freely after that.

[Frankenkit]

I can see that working, just wondering how you lock it in place after that?  I'm using threadlock so it doesn't unscrew... just sayin' havin' one of the butterfly screws come out would ruin your day... 

[BlindJoe]

Ya, that could be bad  . They are still tight, just not so tight that the butterfly binds in the carb body. If you have the stock screws they should be peened at the ends to keep them from coming out. The thread locker should still do its job even if the screws aren't in as tight as possible.

[mystic_1]

Try loosening the screws slightly, opening and closing the choke a few times to let things settle into place, then re-tightening the screws.

mystic_1

[Frankenkit]

SHE'S RUNNING! SHE'S RUNNING!!!

 

Took the carbs home last night, sorted out the choke problems as mentioned here, took 'em in today and hooked everything up (took the time to lube my throttle cables a little, too, b/c my clutch cable's new and like buttah)

She growled a little even w/o the choke.

Pulled the choke and on the first try fired right up like she'd been running all day. 
Smooooooth as butter, sounded nice and clean. Needs some adjusting for the idle screws, synch the carbs, but hallelieuja, she's running!

She blew some white smoke out the left pipe (have 4-into-2) but that might be a mixture thing, or due to all the cleaner I've been putting through the carbs. 
 

Friday night I'm going over to put the airbox on, maybe adjust some things, then Saturday I'm taking the rear wheel in to get a new tire put on. (I did the 5-gal-bucket + two tire spoons method on the front and I just can't find it within myself to do that again)

...then a test run to make sure the tranny's working. 
This is a truly great day...
two years in the making...
the first time I've heard her run on all four!

[BlindJoe]

Good Job! It's a great feeling isn't it?

[Frankenkit]

 
Incredibly!

[mystic_1]

Excellent.


mystic_1

[750goes]

Hey Kitsune - knew you could do it - great work - now have some great riding and bask in the glory of knowing you "made it run" by yourself - with just a little help from friends......

[troppo]

It always feels so much better when you hear them run for the first time and you think "I made it run".
Kinda Dr frankenstein in a way lol "Life, I have created LIFE"

[Frankenkit]

Hey, bad news...

The kreem in my tank went to hell.  Bike ran great off  just a bit of gas in the carbs, put the tank on and performance got worse, and worse, and...
...

Took off the tank, realized several awful things about the kreem in the tank.

"somebody" kreemed my tank without taking the filter out because the filter fit so flush it was never seen, so it's not just f*cked but it was glued in there so my mechanic destroyed it trying to remove it.

The tank is going to the radiator shop to get cleaned out and sealed, (there's muddy looking rust all over under the peeling kreem) 

Pretty sure the carbs are ok, because all the gas had to go through an inline fuel filter before reaching them.   

Wondering if anyone knows where I can get an in-tank filter cheaper than the $25 from Honda (that still works)

going to powdercoat the tank after that.  Not sure what color.  Thinking maybe black.

Murphy's law owns this bike.