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Some folks on the forum have no starting problems. Others report hard starting. My bike (rejetted) was a bear to start before rejetting and somewhat easier afterwards. I'm talking fairly cold weather 10-40F. Once we're into good weather, never a problem. There's a variety of opinions on the Forum that describe how to start your bike (choke position, allow the carb 'heaters' to warm things up, etc) which may or may not help your specific machine.

One thing most of us agree on is .... don't give the bike any throttle when starting cold ..... has to do with the starting circuit having enough vacuum to function, I believe.

I also have two other carburetted bikes in the garage, the old R100GS, and the Kawasaki W650 (also equipped with Keihin carbs like the Bonnie, but without heaters), and either of these bikes start much easier in very cold weather than the Bonneville. The FI equipped ST1300 .... well, obviously, she starts like a car, even after sitting for two months. (I may find she drives just like a car, too, come springtime ...hope not).

When I get ambitious, I'm going to ck out fuel levels in the float bowls. Because when cold-starting even in slightly warmer weather, she wants to stop a few times before going into a steady idle mode, and shaking the bike back and forth when the engine starts to slow brings the idle speed back up, and she continues to run. I think it may have something to do with sloshing the fuel around in the bowls .... maybe getting fuel a little higher in the bowl. Mystery to me.

Bob
 

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With stock pilots (40) in this cold weather mine would take 7-10 tries before starting.
I just re-jetted to 42 pilots for open pipes, and whaddaya know, it starts first time just like it did in the summer
G
 

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Yeah, 10 - 12 starts in NJ too. So if we get a reading from Maryland then North Carolina and Maine, we can calibrate the number of starter pushes to the latitude. Divide by a constant times the temperature and we'd know what size jets to use, then convert to metric. Uh.. wait...
 

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nacho -

What kind of bike do you own? My bikes have a heater element on the carbs that kick in when the temp falls below 40 degrees. The key is to pull out the choke, turn on the key, and then wait at least 10 - 20 seconds (for the carbs to warm up) before pressing the starter button.
 

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Yeah, mine started acting up this winter, although it was OK last year. Eventually diagnosed the ignition coil arcing out when there was any damp in the air. Replaced it and no problems since.

Best mechanic I know, Paddy, reckons that the insulation in Triumph coils starts to break down after 3-5 years. I've learnt to trust his judgement over the last 25 years... :cool:
 

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Takes me between 5-15 tries when the weather is between 10 and 40 degrees. Turning the ignition on for the "carb heaters" doesnt seem to help. I just chalk it up to the cold, although it is annoying. My bike is brand new.
 

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Had the same problem (5 to 10 prods of the electric leg before she'd idle when cold). Easily fixed by removing the covers from the idle mixture screws and backing them out a bit.

From the factory the left carb was turned out 2 turns from seated, the right carb 1 1/4 turns from seated. Now they're both in the 2 1/2 to 3 turns out, she starts FIRST time every time now, even when it's cold. :upthumb:
 

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The idle screws and pilot jets are the key. Even if you do not modify the pipes or airbox, you are well served to back out the idle mixture screws a bit and put a couple of washers under the flange at the end of your carb needles. It makes up for the lean condition that plagues all bikes that must meet EPA standards. It costs less than a couple of bucks and a little of your time, but makes your bike much better.
 
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