Starting to get cold here in the mornings (33-38) and my girls kinda acting funny, but it's not ha,ha funny. Here's the deal. When leaving out (only when its cold) , after a short choke, I will be riding along,after about a mile or so , she starts to backfire, stutter, and even attempt to stall while moving along at a good clip. This is with the the choke off ofcourse. After she is finished with her dramatics (5-8 seconds), she runs like a champ for the rest of the ride. And I mean really good! So my question is ..... Is this a normal thing? It only started after it started to get cold round here. To be fair though, I will tell you that I made the following mods around the same time. 1.Removed the AIS. 2. Added a barons manifold 3. Drilled ten 1/2 inch holes in my stock airbox. Jetting remains the same as before : DJ175 main , DJ needle 4th groove , stock spacers in the stock location, stock pilot, pms 3 turns out. Doc , I have not had a chance to do a real (interstate) WOT test yet. Anyway, This is my first yamaha motorcycle and my first aircooled twin, so you could see where I might have some questions. Bear

Bear
Sounds to me like she's still cold.. takes a while to warm up
At those temps the full choke for about half a min then half choke for about
2 1/2 min and then choke off and she may still cough a little til warmed up.. its a cold blooded v-twin with a cv carb
Runs like a piece of $#@&* til warmed up then runs good

Mine acts the same way.... so did the Hardley

See what Doc has to say..<br><br>Post edited by: Pop Rivet, at: 2006/11/02 15:11

Little bit of ice forming or trying to go through once you get going?
This time of year I keep Seafoam in my tank just so I don't get iced up. Just a blind ass guess.

sounds like you have a borderline lean condition made worse by 10 holes and cold weather suggest richer pilot setting and maybe one notch on needle look ay your plug color these bikes are on the lean side to begin with . jb

I agree with PopRivet. I get similar symptoms this time of year when the temps are the same.

When it's that cold you're going to have to use the choke a bit longer. I start with a full choke, put my gloves on, push the choke in halfway and take off slowly. About 1 mile (little above freezing) to 2 miles (little below freezing) later, I push the choke in all the way.

If I don't leave the choke on until the bike is reasonably warmed up, it will buck like a bronco with the slightest throttle input.

It's best to tune your bike at the time of year that you do most or your riding (summer I hope ). Then in the fall turning your PMS out a bit helps (you're almost at the limit).

Doc

I will be riding along,after about a mile or so , she starts to backfire, stutter, and even attempt to stall while moving along at a good clip. This is with the the choke off ofcourse. After she is finished with her dramatics (5-8 seconds), she runs like a champ for the rest of the ride.

In search of enlightenment hihack. If it needed the choke on wouldn't it run bad right from the start? If after a mile it acts up for only a few seconds at a steady pace wouldn't that be something else? Maybe not ice but why would it only do it for a few seconds and after the bike has warmed up some?

Thanks

Musky wrote:
In search of enlightenment hihack. If it needed the choke on wouldn't it run bad right from the start? If after a mile it acts up for only a few seconds at a steady pace wouldn't that be something else? Maybe not ice but why would it only do it for a few seconds and after the bike has warmed up some? Thanks

In most cases, for the limited info usually provided, it's hard to pinpoint exactly what's happening, so I try to generalize.

As the air gets colder (probably as we speak in MN ) it becomes denser. The cold air temps result in a longer time before the engine reaches it's operating temp so you need to use the choke a little longer. The bike will still be cold after a mile at 33-38 degree air temp. The choke enriches the lean condition until operating temps are reached.

If the carb is really lean then you will have to use the choke for a long time.

But you may be correct ... it could also be carb icing, especially under humid conditions. That's not to say it cannot occur in the summer.

Doc

Musky

Pilots are aware

When the temperature is between
20?F and 70?F with visible moisture or high humidity, one
should be on the alert for carburetor ice. During low or
closed throttle settings, an engine is particularly susceptible
to carburetor icing.

A motorcycle travelling along is is in an open throttle position

When flying an airplane and on descent you put on carb heat to avoid carb icing

I doubt very much if this is what is happening here<br><br>Post edited by: Pop Rivet, at: 2006/11/03 04:10

i started to have a bit of a problem with carb icing last winter. first time ever, but it was sitting around -5 to -10&ordm;c during jan to feb. the carb heaters aint working quite right, and shame on me, i ain&acute;t sorted it.

as doc said, cold mornings the old girl does need a couple of miles of choke before she&acute;s happy enough for some banjo string throttle cable games.

benson48 wrote:
sounds like you have a borderline lean condition made worse by 10 holes and cold weather suggest richer pilot setting and maybe one notch on needle look ay your plug color these bikes are on the lean side to begin with . jb

Okay which is it, do these bikes usually come new lean or rich? Seems every day I read something contrary to what I read the day before.