Author Topic: Finally she runs well kinda (Read 4306 times)

Bowman · « **on:** December 18, 2006, 12:50:40 PM »

I finally got her to start now I am fighting with the adjustment.

When the choke is pulled all the way out it idles at 500 to 1500 but if I try to push it in even after warm up it jump to like 4000rom and I have to either yank the know out again or kill the engine.I also have white smoke coming out the number 1 and 2 exhaust.

I have no clue where to start to tune these thing since the clymer manual is kinda confusingabout the 81-82 carbs.

Any suggestions?

kettlesd · « **Reply #1 on:** December 18, 2006, 02:36:25 PM »

Yes, i'd agree that it sounds like you have a very lean condition in those carbs - and are quite likely out of sync as well. White smoke is probably water vapour, but be careful its not actually a light shade of blue - it can be hard to tell sometimes. Check it in good light.

Start with your usual tuneup procedures. Check the Valve clearances first, ignition timing, spark plug condition, and do a compression check. All good?? Then move on to those carbs.....

Constant Velocity carbs are no harder to work on than the older-type Slide Piston carbs, but they are more sensitve to airleaks. Just try running them with no airbox & filter and see what i mean. Be SURE the carb boots are fitted properly and tightened, and that you have a good, clean airfilter in place.

Read the FAQ's on complete carb service - the principles are the same for your CV's, only you have a spring and diaphramn under the top caps instead of the linkage-actuated pistons. But clean is clean no matter the carb type. Be sure the jets, jet nozzles, airways, needles, are all SPOTLESSLY CLEAN!!!!!! Be sure your float height is correct, as having it off will cause that particular cylinder to be rich or lean.

Now put in some fresh gas, start it up and marvel at that awesome early 80's technology...... lol. Set your idle speed and after its warm you can balance the vaccuum - but only if everythign above is perfect. Syncing the Vacuum is the last thing you do.

Let us know how you make out.

TwoTired · « **Reply #2 on:** December 18, 2006, 03:58:19 PM »

Unless you like tuning the carbs twice (or more), always begin carb tuning with a thorough tuneup, so you know all the valves are opening the same amount and the spark is happening at the right time on properly sparking plugs.

But, it sounds like you just got the bike running after a long sit. Correct?

If so, the smaller slow jet orifices may still be clogged on one or more carbs. One diagnostic technique is to monitor the head pipe temps. Cold ones indicate lack of firing and possible fuel starvation. If they are clogged, you can get a hot pipe at high throttle setting and a cold one at low throttle setting.

I use the flash touch method to compare the temps.

White smoke is steam, usually, vaporizing the condensation inside the exhaust pipe. Sounds like one and two are heating up.

Er, you can get it to idle at 500 RPM?

It's always nice to have the year and model of the bike. There are significant differences between the SOHC4 models.

Cheers,

Bowman · « **Reply #3 on:** December 19, 2006, 12:31:46 PM »

I am slowly working through the list now as for the smoke there is alot of it and it doesn't seem to stop I am reseating the boots now and then I and going to set the choke adjust jets and everything is to the clymer defulat so I have a good starting point.. Yhea it with hold at 500 it is not happy about it but it does do it.Weirdest thing I have ever seen

kettlesd · « **Reply #4 on:** December 19, 2006, 12:37:12 PM »

Keep us posted. No way my machines will idle at 500 btw. - at least not very long......

jdpas29 · « **Reply #5 on:** December 19, 2006, 04:25:27 PM »

set your valve clearance

set your carb float height (if needed on this model) and clear out the main jets/emulsifier tubes. synch carbs. set mixture screws on carbs (if there are screws on this model)

make sure your carb to intake boots and airbox to carb boots are tight and don't leak (good way to check is to spray them with carb cleaner and listen for a change in RPM

set breaker point gap and clean breaker points

check/clean plugs or replace if super old and crusty

set timing chain tension

Bowman · « **Reply #6 on:** December 20, 2006, 11:16:02 AM »

OK thats it I give up I can only take messing with carbs so long before I have to walk away or blow up at said thing and beat the mess out of it.This thing is possed Get it to idle poorly (popping and chugging at 1,500) then turn it off come back 1 minutes later crank it it jumps to straight 4000 before I can get to the kill switch.Noting I do to the carbs from checking for leaks to adjusting seems to be making any difference.I like my bike but my nerves have finally given out.I have worked on vw beetles with less attitude than this darn thing and that is saying something.

750goes · « **Reply #7 on:** December 20, 2006, 12:22:08 PM »

are your throttle cables a bit sticky as well......??

Bowman · « **Reply #8 on:** December 20, 2006, 12:30:30 PM »

Ok after a brew I went at it one last time got it idleing a 1,450 choke off 2,000 choke off.Timing cam chain valves cables all cleaned and factory set.I cleaned the cars 3 times out of frustration so I got them shiney in and out.Now idles decent with a light popping sound and a occasional light back five ever 5 minutes or so.I Beleive I have it down to just needing to be synced really really badley.
I am currently trying to find a shop that will A work on a cb650 and B not quote 400 bucks to adjust and sync the carbs.

P.S. I ran dual iso carbs on my bug so it was almost the same as having quad carbs.Then again it also had a sync tool you could buy for 24 bucks

hcritz · « **Reply #9 on:** December 20, 2006, 12:31:28 PM »

Hey Bowman....
I'm in Starkville, MS....Pretty fair mechanic here...all else fails...load it up and bring it down...I can give you a hand.
Can't be anything too awful...these are really pretty simple machines.
ED

hcritz · « **Reply #10 on:** December 27, 2006, 02:02:56 PM »

Hey Bowman...
did you ever get your bike sorted out???

Bowman · « **Reply #11 on:** January 07, 2007, 05:24:01 PM »

I am currently sans carbs I have them off for the 4th time to clean and try my hand at rebuilding them.

hcritz · « **Reply #12 on:** January 08, 2007, 01:30:53 PM »

If you need help...let me know..
I have the carb sync tools etc here.

Bowman · « **Reply #13 on:** January 11, 2007, 11:49:22 AM »

Ok quick update I reinstalled the carbs and airbox today carbs completly rebuilt.After priming the carbs nothing I can't get it to start man I really stink at this carb stuff on this bike. $:-\$

mlinder · « **Reply #14 on:** January 11, 2007, 12:25:14 PM »

Quote from: Bowman on January 11, 2007, 11:49:22 AM

Ok quick update I reinstalled the carbs and airbox today carbs completly rebuilt.After priming the carbs nothing I can't get it to start man I really stink at this carb stuff on this bike. $:-\$

Got yer killswitch turned to the 'on' position?
Just wondering, I've exhausted my right foot trying to kick over my bike a couple times, then realized the killswitch was off .:/ (shhh, don't tell anyone, ok?)

Bowman · « **Reply #15 on:** January 11, 2007, 12:28:26 PM »

Switch on battery charged it just spits like it wants to fire but doesn't

BobbyR · « **Reply #16 on:** January 11, 2007, 12:49:41 PM »

Quote from: TwoTired on December 18, 2006, 03:58:19 PM

If so, the smaller slow jet orifices may still be clogged on one or more carbs. One diagnostic technique is to monitor the head pipe temps. Cold ones indicate lack of firing and possible fuel starvation. If they are clogged, you can get a hot pipe at high throttle setting and a cold one at low throttle setting.

I use the flash touch method to compare the temps.
Cheers,

I actually have a less painful method for checking pipe temps. Put a drop of motor oil on each pipe near the flange and see how long it takes to burn off. If 3 go quick and one does not, that pipe is running much cooler. Nice visual check and no burned fingers.

Bowman · « **Reply #17 on:** January 11, 2007, 01:08:48 PM »

I probably flooded it in my excitement to try and start it I am giving it a chance to dry out now.

TwoTired · « **Reply #18 on:** January 11, 2007, 01:11:24 PM »

Quote from: BobbyR on January 11, 2007, 12:49:41 PM

Quote from: TwoTired on December 18, 2006, 03:58:19 PM
If so, the smaller slow jet orifices may still be clogged on one or more carbs. One diagnostic technique is to monitor the head pipe temps. Cold ones indicate lack of firing and possible fuel starvation. If they are clogged, you can get a hot pipe at high throttle setting and a cold one at low throttle setting.

I use the flash touch method to compare the temps.
Cheers,

I actually have a less painful method for checking pipe temps. Put a drop of motor oil on each pipe near the flange and see how long it takes to burn off. If 3 go quick and one does not, that pipe is running much cooler. Nice visual check and no burned fingers.

Oil on hot chrome will often turn the chrome blue/black. Flash touch works well for those who don't wait to feel heat before removing their fingers.

The IR temp guns are getting pretty cheap these days. I think I saw one for $19. I can't expalin why I don't own it, though.

Cheers,

hcritz · « **Reply #19 on:** January 11, 2007, 01:24:49 PM »

Hey Bowman...
I'll be on the coast working on the sailboat...but next week and weekend...I should be here.
If you don't get things straightend out...I'll give you a hand.

ED

Bowman · « **Reply #20 on:** January 11, 2007, 08:50:48 PM »

Ok quick update tried her again it sounds like it really wants to start just not quite getting there.
What should I set the pilot screws (my limiter caps have been removed),idle adjust screw ,and the synchronizing adjustment screws .I think if I can get a base line setting on everything it will start then I can dial them in.

kettlesd · « **Reply #21 on:** January 12, 2007, 04:00:15 AM »

Pilot Screws should be set at 1 1/4 to 1 1/2 turns out from lightly seated. Idle screw, set to desired rpm after she lights - no biggie.

CV-carbs..... my advice is don't frig with the sync screws until it is running and you can do a vacuum test using the proper guages!

You've heard of "bench-syncing" probably - where you adjust the screws so a 1/8" drill bit will just slip under the slides. This applies to the older slide-piston carbs and not your CV's. On the CV's the sync screws do not raise the slides at all, they actuate the plate. As long as your throttle plates are all opening/closing to the same degree you have a good baseline to start.

Bowman · « **Reply #22 on:** January 12, 2007, 06:59:19 AM »

Well I am started back tinkering this mourning all I have gotten so far is a flaming backfire

kuyarico · « **Reply #23 on:** January 12, 2007, 07:13:36 AM »

Quote from: Bowman on January 12, 2007, 06:59:19 AM

Well I am started back tinkering this mourning all I have gotten so far is a flaming backfire

Are there actual flames coming out your exhaust?

kettlesd · « **Reply #24 on:** January 12, 2007, 07:16:57 AM »

Flaming backfire is raw gas being burned inside the exhaust. Sounds like your flooding still. Are you sure float heights are set right and the needles are sealing properly?? Bowls could be overflowing into the intakes.

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Author Topic: Finally she runs well kinda (Read 4306 times)

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