Motorcycle won't run on choke

[jmint]

I can start the motorcycle overnight cold without the choke, but it won't start with the choke full on.

Over the summer, I could start it with the choke on, but now that temps have dropped a bit, it doesn't work anymore.  The slider is working on both sides, and all SE valves are being pushed.  The handle bar cable is difficult to move as expected, so I'm planning to do John Schmidt's choke cable delete here shortly and get that side of the system out of the way.

In the summer, the choke/enrichener system functioned from what I can tell as intended.  It idled at around 2k rpm with the choke on, then dropped to approx 900 - 1k when I took the choke off.

All of this started prior to a desmog.  If I need to pull the SE valves and clean, that should be something I can do with the carbs still attached to the motorcycle, right?  Any ideas appreciated.

[The emperor has no clothes]

A couple questions. Does the bike start without the enrichener ? If it does, will the "choke" raise the rpm's ? How many miles on the air filter ? (I guess it was 3)

[jmint]

A couple questions. Does the bike start without the enrichener ? If it does, will the "choke" raise the rpm's ? How many miles on the air filter ? (I guess it was 3)

The it will start without the enrichener.

The "choke" will kill it.

Maybe 2k miles on the air filter.

[Ricky-D]

I can start the engine, and the engine will run, if at first I first engage the enrichener circuit before cranking the  engine.

The engine will shut down,  if I have started it, without the enrichener engaged, but then engage the enrichener circuit.

The engine will run at higher rpms when cold and the enrichener engaged. As the engine warms, it starts to stumble a bit, however disengaging the enrichener circuit restores correct idling.

With a first start of the cold engine it may start without the enrichener engaged, but only with difficulty, and it wont idle worth a darn. It'll stall if I then engage the enrichener circuit.

I've at times have run the engine for long periods where I forgot to disengage the enrichener circuit. Didn't notice much until I have to stop and the engine strains to idle correctly.

The engine has without fail, on the first start, started immediately, with the enrichener circuit engaged, and idled up perfectly every time since I bought it new.

I have done no work ever on the carburetor system. Just drain a little from each float bowl every year or so.

My bike is ridden year around.

[jmint]

I can start the engine, and the engine will run, if at first I first engage the enrichener circuit before cranking the  engine.

The engine will shut down,  if I have started it, without the enrichener engaged, but then engage the enrichener circuit.

The engine will run at higher rpms when cold and the enrichener engaged. As the engine warms, it starts to stumble a bit, however disengaging the enrichener circuit restores correct idling.

With a first start of the cold engine it may start without the enrichener engaged, but only with difficulty, and it wont idle worth a darn. It'll stall if I then engage the enrichener circuit.

I've at times have run the engine for long periods where I forgot to disengage the enrichener circuit. Didn't notice much until I have to stop and the engine strains to idle correctly.

The engine has without fail, on the first start, started immediately, with the enrichener circuit engaged, and idled up perfectly every time since I bought it new.

I have done no work ever on the carburetor system. Just drain a little from each float bowl every year or so.

My bike is ridden year around.

1.  I cannot start the engine with the enrichener circuit engaged.

2.  Yes, the engine will shut down if the enrichener is engaged after the engine is started, however, this is new to cooler air temps.

3.  Yes, the engine will run at higher rpms when cold and enrichener engaged previously when air temps were warmer.  When the engine warmed up, I never had a stumbling issue.

4.  Starting a cold engine without the enrichener is difficult, and idle is terrible.  It will stall if I engage the enrichener.  I have to idle up with the throttle to keep it running.

[Bone]

98 Tourer

I put the choke on all the way.
Push the start button it cranks 2 or 3  revolutions and fires.
Then I can touch the throttle.
Touch the throttle while it cranks it will not start.

[gordonv]

Sounds normal, for a Valkyrie.

John's mod is great, but if you don't need the enricher, then don't bother.

I've had 3 different IS models already. Each was different. All you need to learn how to do is how to start it. If you don't need the enricher to start it, then don't. If you only need it to start it, then off, then do it. If you need it to run higher rpm till the engine warms in 1-2-5 minutes, then do it that way.

[Steel cowboy]

How old are the plugs. When I was living up north “Long Island”, worn plugs made for hard starting in colder weather.

[Jims99]

Mine was doing the same thing. Mine was slight vacuum leak. I desmoged, rebuilt carbs and replaced intake o-rings. Florida weather I don’t need enrichers unless it gets below 65 and she runs perfect. These bikes run on the rich side anyway, so if it’s set up right, most will start like mine (in hot climates). It’s nice to get on, hit the button and go any temp. Almost like fuel injection. LOL.

[jmint]

Plugs aren't bad, or at least they weren't bad when I checked them in March when I picked up the bike.  No fouling, but you're right, Cowboy, I should probably pull them again.

Jims, where did you find the vacuum leak?  I have to tear back down to fix a water leak at the block water pipes anyway.  I think the only thing left after the desmog would be the other (4) intake caps, right?

[Steel cowboy]

There are different ways to check to see if you have a bad vacuum line
you can use WD-40 sprayed behind the carburetors or if you feel reckless spray ether.
if there is a vacuum leak the engine RPMs will Rev up.
I believe carb cleaner will also work.

[..]

I can start the motorcycle overnight cold without the choke, but it won't start with the choke full on.

Over the summer, I could start it with the choke on, but now that temps have dropped a bit, it doesn't work anymore. 

My brain hurts.

[turtle254]

There are different ways to check to see if you have a bad vacuum line
you can use WD-40 sprayed behind the carburetors or if you feel reckless spray ether.
if there is a vacuum leak the engine RPMs will Rev up.
I believe carb cleaner will also work.

W D 40 changed propellent from propane to co2.
Doesn't work's that way any more.

[Toovalks]

I could be stupid here but.... I'd guess you are way rich in your idle circuit. Vacuum Ie. reduced manifold pressure drops the temperature (PV=nRT) of the incoming air. Cooler temps mean poorer atomization of the fuel load.  Hence poor ignition. When days were warmer even though you were still way rich with the choke on... the fuel was atomizing better in the warmer air in our very short manifold runners.

[jmint]

There are different ways to check to see if you have a bad vacuum line
you can use WD-40 sprayed behind the carburetors or if you feel reckless spray ether.
if there is a vacuum leak the engine RPMs will Rev up.
I believe carb cleaner will also work.

W D 40 changed propellent from propane to co2.
Doesn't work's that way any more.

After the desmog, what vacuum lines are left?  Not trying to be an ass, I'm concerned that I'm missing something that's obvious.  I've only had the Valk since March this year, still learning the ins and outs.

[Jims99]

Plugs aren't bad, or at least they weren't bad when I checked them in March when I picked up the bike.  No fouling, but you're right, Cowboy, I should probably pull them again.

Jims, where did you find the vacuum leak?  I have to tear back down to fix a water leak at the block water pipes anyway.  I think the only thing left after the desmog would be the other (4) intake caps, right?

my vacuum leak was a slight split in one of the emissions line (witch was removed with Desmog)
Also the vacuum caps can split and leak even if newer. Make sure they are ones that can handle the heat. Automotive ones can’t. I get mine from redeye.
Also the intake gaskets can cause the same issue, (again, redeye)
I don’t know why a vacuum leak causes it not to start on choke, makes no sense to me, but it does effect it in that way.

[yrunvs]

Here's my 2 cents.

My Valk will not start by first engaging the enrichener and then hitting the go button.

My Valk will start without engaging the enrichener but idles badly and then dies.

I have to start my Valk without the enrichener and then immediately rev it up while at the same time engaging the enrichener and then it will stay at high idle for the needed amount of time until I disengage it.

These fat lady's are all unique.

[Toovalks]

When you go to start your bike,with  "zero" throttle,(very small crack under the butterfly)... you are relying on the enrichner circuit in your carbs to provide both the air path around the butterfly and the fuel , if the vacuum created by your piston on the intake stroke can draw it air through a leak some where else in the system... it doesn't pull everything it needs to go boom.

[The emperor has no clothes]

When you go to start your bike,with  "zero" throttle,(very small crack under the butterfly)... you are relying on the enrichner circuit in your carbs to provide both the air path around the butterfly and the fuel , if the vacuum created by your piston on the intake stroke can draw it air through a leak some where else in the system... it doesn't pull everything it needs to go boom.

Yes, these constant velocity carbs miles ahead of the simple Mikuni's and Keihin's from early bikes.

[jmint]

Meathead, Toovalks, Jims,

Since I have to take it down anyway to fix that water leak, I'll go ahead and replace the other vacuum caps, petcock vacuum line and intake seals.  Gonna be down that far anyway, so might as well.

Thanks

[Toovalks]

I really don't believe that vacuum leak is the problem. If you can kill the cold engine by applying the choke...you are drowning the spark...TOO RICH... especially when the temps are cooler.

[Steel cowboy]

After the desmog, what vacuum lines are left?  Not trying to be an ass, I'm concerned that I'm
missing something that's obvious.  I've only had the Valk since March this year, still learning the ins and outs.

Answer to turtle, About using WD 40, I have 2 full older cans. Lol
After a desmog, If you are using the stock petcock, there will be a vacuum line from “normally” number 6 carb intake. That would be the only vacuum line left, all other intakes will be blocked off. If you were using a Pingle shut off valve, there would be no vacuum line’s needed.
[/quote]

[h13man]

I use the "choke" after winter layup otherwise, no. It seems to like absolutely none through the season even the other day when it sat for 2 weeks. Seems "enrichen" too much to the point of almost fouling a plug type scenario. Still likes its 2000 mi. B12 treatment thru the season. So far so good @ 21yrs./45,000 mi. though preventive maintenance is going to be implemented this winter on the fuel system along with fork rebuild.

[Jims99]

After the desmog, what vacuum lines are left?  Not trying to be an ass, I'm concerned that I'm
missing something that's obvious.  I've only had the Valk since March this year, still learning the ins and outs.

only line will be to stock petcock. Still have 5 vacuum caps that can split and leak. Also the intake o-rings can cause lean conditions along with loose clamps either side of carbs.

[beebeerown]

yrunvs's suggestion worked for me:

"Here's my 2 cents.

My Valk will not start by first engaging the enrichener and then hitting the go button.

My Valk will start without engaging the enrichener but idles badly and then dies.

I have to start my Valk without the enrichener and then immediately rev it up while at the same time engaging the enrichener and then it will stay at high idle for the needed amount of time until I disengage it.

These fat lady's are all unique."

If the weather is right (?80+ degrees F and not damp?) it will start without the choke on and not with the choke on.  But if the weather is not right then the following works every time:

1. Choke on til it meets high resistance boundary
2. Twist throttle a hair, hit starter button, immediately release throttle
3. Slowly push choke into high resistance area and warm up as necessary (usually not more than a minute)

Thanks for your help!

[h13man]

I forgot to mention that I use NGK Iridiums which are far superior to regular NGK and last much longer than stock. I've had to different plugs go bad just past 10,000 mi. each time and of course on cold starts. I've got 14,000 on the iridiums so far and no issues cold starting even after winter layup as it started immediately with enrichener applied within 3 seconds. BTW I think the manual states plug replacement every 8,000 mi.?

[Pappy!]

There are different ways to check to see if you have a bad vacuum line
you can use WD-40 sprayed behind the carburetors or if you feel reckless spray ether.
if there is a vacuum leak the engine RPMs will Rev up.
I believe carb cleaner will also work.

W D 40 changed propellent from propane to co2.
Doesn't work's that way any more.

Its easier than those anyway take a propane torch and do not light it but turn the valve on and use it around the carbs and intake runners. RPM will pick up if the propane hits a leak area