Cold idle problem - do i have my facts straight?

[Kiwi]

OK, my problem is that the bike wont idle when cold. It stalls.
idles fine when warm, and seems to run pretty good.
If i give it a little gas when cold, it idles fine. 
Also, if i put the choke on when the bike is nice and warm, it kills the engine.

So, if i understand this correctly.... The choke limits the amount of air to the engine, which results in a rich mixture.  I can adjust this mixture with the idle set screws (i think i called them the right name, recessed brass screws, back one is hard to reach).  If i screw them in, it limits the fuel flow, therefore leaning out the mixture?

So, if i have the choke on, but am giving it a little more air ( twisting the throttle ), i am effectively leaning out the mixture.
So... if i turn the screws in a bit, that should the right direction to help make the bike idle properly when cold? ( i assume this would raise the idle)
As it is now, the idle screw is quite far in, and is a little harder to turn than normal.

The carbs are synced ( i use the long plastic hose taped to a piece of wood), well at least pretty close.

Do i have the right idea?
Thanks !

[Rikugun]

You're understanding of a "choke" is correct. Unfortunately the term choke is a misnomer when it comes to certain carbs, Vision included. The Vision uses what is referred to as an enrichener. It doesn't move a plate to limit air but rather opens a passsage that allows a rich mixture of fuel to enter.

I'd start with the basics - clean carbs, clean air filter, proper float level, no vacuum leaks including YICS, etc. Then adjust the idle mixtures, idle speed, and sync when the engine is at operating temp. Everyone has their preferred method and number of turns on the screws. A reliable source claims 1.5 front/3.5rear as a good starting point for '82 carbs. Keep the engine barely running (very slow idle) when adjusting the mixtures. Turning the screw out gives a richer mixture, in leans it out.

How cold is it when it won't idle? On mine, as it gets colder outside it will start with the enrichener full on but idles seemingly slow 'til some heat develops  - a minute or so? Then the idle starts to climb and I have to adjust the enrichener lever towards off to maintain a reasonable idle speed. If you've had to turn your idle screw in further then its been to keep an idle, I'd think the carbs may have gotten some debris which is affecting the idle circuit.

[AdvRich]

You may still have clogged choke circuits in one or both carbs... The passage at the end of the plunger is rather small and should be chased clean with a very small section of wire ... also check condition of the rubber seals. If you didn't want to pull the carbs again, you could pull just the plungers and carb tops while still hooked up. I use a pair of new mechanics nitrile gloves to fill the throttle bodies while doing so to prevent an oops FOD moment from happening. If the carbs are out of sync enough and there is not enough enriching for the weaker cylinder than the bike will have a hard time running cold as it will be "dragging" too much from lack of fuel. Once warm, friction is less and it will idle... With a good ear, you can hear the engine working harder on one cylinder when idling cold vs warm. Your very close  to normal operation for it to be in this stage of idling. Some cleaning may be enough to get the bike to idle on choke when cold and get you through this stage of operation. Syncing is another matter.

Carb sync is more than the two plates opening close to one another; its a measurement of the vacuum within each venturi and that vacuum is created by the cylinders pulling the air through the carbs. So, if one cylinder is slightly stronger in suction it will have a higher flow rate even if the two throttle plates were set exactly the same. A set of vacuum sticks will get them dialed in, but it is best to make sure the valves are within spec, and other areas that effect flow, like compression, exhaust, etc., before more time and $ went into syncing.

Rich

[Rikugun]

Those are some good bits of advice Rich. It reminds me to mention the "well" in the carb body that a brass tube sits it. Apparently there is a small passage at the bottom of the well that is also vulnerable to partail or complete blockage and a small piece of wire is required there too. CdnLouie has talked of this and if you search his posts I'm sure you'll find more info.

edit: here's one of those discussions
http://ridersofvision.net/rovforum/index.php?topic=12894.msg117297#msg117297

[Lucky]

note that one of those orafaces is adjacent to the cast tube in the float bowl.  it's opening sits in the bottom of the bowl where all the crud collects. this is one of those passages that has a huge effect on starting performance...

[AdvRich]

Those are some good bits of advice Rich. It reminds me to mention the "well" in the carb body that a brass tube sits it. Apparently there is a small passage at the bottom of the well that is also vulnerable to partail or complete blockage and a small piece of wire is required there too. CdnLouie has talked of this and if you search his posts I'm sure you'll find more info.

edit: here's one of those discussions
http://ridersofvision.net/rovforum/index.php?topic=12894.msg117297#msg117297

Thanks, you too Gary. Yep, on cleaning the "well" as well. I was kind of thinking that Kiwi already went through the carbs before this run up, and a quick top off might get things sorted without R&R the carbs again, but perhaps I read too much into the post.

So Kiwi, how's it going?   

[Kiwi]

I've been at work, so no progress today.
I could swear the carbs are clean... I've doe it soooo many times.  The last cleaning was a 24 hour soak in pine sole, clearing out the passages w/ an air compressor.
Maybe another cleaning will also give me a better starting point.
I've been riding the bike to work like this.  I just let it warm up a bit, and jam the throttle slightly open while it warms up and i stand around...
I think i'll get her warmed up on saturday, play with the setting one more time, then do another cleaning if i dont have any results.
I have actually managed to go backwards in regards to reliability with this bike, it ran great last summer !

[AdvRich]

Yeah, the Vees and well any other 30 y.o. scoot offer up plenty to do to keep them top notch... either a little at a time or an all in one redo like Tiger's work. The initial price sure is right though and it does make a great commuter with the shaft, fairing and heated lowers for the edges of the riding season. Fuel milage is good too, mine used to get 50 to 52 mpg regularly on regular. Sounds like your not too far off from getting it back to last seasons performance.

I'll throw this in the mix as well for the cold running symptoms, I had a situation where the bike would drag one cylinder when firing from cold in the cold and then after a bit would start cutting in. Ran fine when warm and adding choke when warm was too rich, so I thought at least the chokes seem to be working. I switched the front plug cap to rear and vise versa... and the same problem only it was now the front that was not running. I bought two new plug caps (and plugs for good measure) for it and all was fine. Never had a plug cap go bad, so I never gave it much thought. Don't know if this could be part of the solution for your Vee as well.

[Kiwi]

Plug cap? I assume you mean the end of the spark plug wire that goes on the spark plug?.
My wires are about 2 years, maybe 3 years old.  How long do they typically last.  The spark plugs are the same age as well.

[AdvRich]

If you replaced the wires just two to three years back, as opposed to the original 30 y.o. units, then they are probably good to go. The plugs go by mileage, riding style, and look for wear and out of spec gap. I'm offering up that it may not all be the enriching circuit as you say it stalls out when warm when you add choke... and you've cleaned the carbs (at least once). If, when warm, it starts to lubber and smells rich when you add more choke (before it cuts out), than it's a good chance that both choke circuits are delivering the goods. Bummer the exhausts are mixed on most Vee systems as a quick sniff test and listen at each muffler would help with isolating/diagnosis.

Does your Vee sound like it is trying to idle on one cylinder when doing the cold, choke on idle startup/test?

Rich

[Kiwi]

If you replaced the wires just two to three years back, as opposed to the original 30 y.o. units, then they are probably good to go. The plugs go by mileage, riding style, and look for wear and out of spec gap. I'm offering up that it may not all be the enriching circuit as you say it stalls out when warm when you add choke... and you've cleaned the carbs (at least once). If, when warm, it starts to lubber and smells rich when you add more choke (before it cuts out), than it's a good chance that both choke circuits are delivering the goods. Bummer the exhausts are mixed on most Vee systems as a quick sniff test and listen at each muffler would help with isolating/diagnosis.

Does your Vee sound like it is trying to idle on one cylinder when doing the cold, choke on idle startup/test?

Rich

You know, it does kind of sound like it may be running one cylinder.  It's not smooth.  It has a tempo like swing music... Ba Bump, Ba Bump etc...
Thats kind of hard to explain in text...
The bike seems to vibrate a lot more when cold as well, more than i remember from last year at least. It's a visible vibration of the bike, again much less when warm.
Also, when cold, giving it a little gas does seem to smooth it out.    Bringing it up to 2k -2.5k revs

[AdvRich]

Well, if it is indeed only running on one cylinder, and it sounds like it from your description, then you should be able to also hear it "cut in" as that dead cylinder begins to warm up from mechanical friction and electric current trying to move along the ignition pathway. You can put your hands near the exhaust header and feel the heat or lack of to let you know which is not firing. This will help reduce the work load through isolation.

There are several different ways to go once you have isolated the problematic cylinder. As mentioned, a simple plug cap switch test (while the bike and exhaust are still cold) will let you know if the same cylinder is dead or it has reversed. Before pulling the suspected cap, push down on it to ensure that it was correctly seated on the plug. If so then, perform the switch and don't let the caps warm up too much in your hands when switching. If the cap switch test proves a bad cap, then remove & replace it (or both for good measure). If no change, pop in set of new plugs and test again. If still no change, then pull tank, and check ignition lines from cap back to coil, and the primary side connections for the coil. If you have a multimeter, you can further check the primary and secondary paths for the suspected coil. The coil and cap will need to be room temp for the measurement, I think it is about 68 degrees, to verify correct resistance. In my experience coils usually are fine, but the input and output side are the problem areas.

Hopefully it is as simple as a bad cap, or loose, corroded connection. If not, the journey continues...

Have you done much in cleaning electrical connections on the bike like the TCI terminals, grounds, side stand switch, fuse block, etc? At the least, they all have to be visited at some point to rid the gremlins of places to hide on these aging scoots.

Cheers, Rich

[Kiwi]

From a previous test, both cylinders seem to warm up at the about the same rate.
I pulled the spark plugs from both, pictures included.
Both were dirty on the outside ( of the engine ) with an oily/dirt residue.  I am going to buy some new spark plugs anyway, they are cheap.


Here are two videos
http://www.youtube.com/watch?v=21EOZ-iB30A  - I'm giving it gas to keep it running in the beginning.

http://www.youtube.com/watch?v=pyXP2Njl49g    1.5 turns on the front, 3.5 on the back, works better but still dies.

[AdvRich]

From the sound of the vid, don't worry about ignition as it is running on both. The amount of oil on that one plug though is puzzling, is that valve cover leaking down into that area? Otherwise, make sure the spark plugs are tight, as loose will cause lower compression and some blow by to creep up the threads, all leading to more challenge for that cylinder.

Take the front carb out another .5 turn and see if that improves it as it sounds like a bit of fuel starvation along with being out of sync.

Don't like the sound of that "tinny" tapping when the camera came around to the left side. Hard to differentiate for sure with the way sounds bounce around for recordings... when was the last valve adjust?

I also hear what sounds like the origins for you ROV handle "Kiwi"?

Rich

[Kiwi]

Well, i did find one possible problem, a bit of the gasket has broken off.
I have never touched the valves, i sense a future project....
Can you do the valves on the bike? any special tools/parts i need to start looking for?

As to the accent, i was born in NZ, lived there for about 13 years and am now in the U.S.

[AdvRich]

Yeah, that gasket popping out will create several different problems.
Yes on valve adjustment in the bike, but it is a bit of work getting to the covers and getting them off. You will need the valve adjustment tool when the time comes. I have one or perhaps someone more local to you would also loan it out. If you've not done a compression test, it would be good for reference.
Better ears will be able to chime in on the "tinny" tap, incase it is by chance the tick, tick sound the starter clutch bolts make when backing out. I've not heard that sound yet, but it could be a possibility too.

I stopped over for a 10 day campervan self tour of the South Island back in '08 when moving back to the states from Australia. I had a great time and look forward to returning to do some of the treks and rent a bike next time round.

Cheers, Rich

[Kiwi]

It shouldn't be the bolts backing out, i followed the recommended procedure on that when i got the bike ( 2-3 years ago )

[Re-Vision]

You can use my valve adjustment tool whenever. Carb gaskets are simple to make.     BDC

[Rick G]

Check for tight valves or an air leak