Cold start in winter 2-stroke

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BlueSmoker

New Member
May 7, 2016
31
0
0
Finland
How is it to cold start those 66cc 2 stroke engines in between -0 and -20 celsius (35F to -4F)?
Do i need to have the bicycle inside at winter? Do cold start harm the piston and cylinder badly? Do the piston easily freeze and stuck? Is it hard to coldstart?
 
Aug 17, 2011
313
8
18
Springfield IL.
If the carb is properly tuned, you will have no issues at all.
You may/may not even need to choke it.
I think its beneficial to let it idle for 30 seconds or so to warm up, but on my daily driver, I just start up and go!
 

crassius

Well-Known Member
Sep 30, 2012
4,032
158
63
USA
engine should work OK with a bit of slow warm up - you probably won't enjoy the ride tho

in the early 60s I sometimes had to ride a motorcycle to work on 0F to 20F days - hurts a lot and with snow on ground one falls down a lot - cover your ears well, as that's where I took some frostbite
 

sbest

Member
Nov 3, 2015
343
2
18
Nova Scotia
How is it to cold start those 66cc 2 stroke engines in between -0 and -20 celsius (35F to -4F)?
Do i need to have the bicycle inside at winter? Do cold start harm the piston and cylinder badly? Do the piston easily freeze and stuck? Is it hard to coldstart?
I have 40 years of snowmobile experience mainly with piston port type 2 strokes. Always kept the sleds outdoors. They will start and run even at -30, but of course, will start better if kept indoors. The oil tends to thicken up on the cylinder walls making initial start hard unless you are using a snowmobile type synthetic injector oil, which is formulated against this. Sled oils are your best choice for near freezing temps.

Forged piston (we have cast) are at large risk in cold temps. Cast not so much but always allow a warm up in any temp. Idling, especially with choke on, tends to foul the plug, so start up and start away on light load, taking choke off when you can.

Yup, coldstarting can be hard. Strong spark, good compression and right gas mix is essential.

Jetting NEEDS to be adjusted for temperature. Jetting that is spot on at 20c will destroy pistons at 0c. Need to richen up considerable for cold temps. Hard to believe that -20c will burn up pistons but it will. Every 10c requires a different jet setting.

This is from last winter:


I run sheet metal screws in the knobs of my MX tires on my KTM in the winter for traction on ice.



Hand guards, "lobster" gloves and full face visored helmet help. As do knee and elbow pads for the inevitable falls on ice. Hips take a beating too.
 

Kioshk

Active Member
Oct 21, 2012
1,152
10
38
Connecticut
What SprinfieldScooter sez: make sure your carb's tuned and you won't have problems, I find that the choke can come in handy on particulary cold days too. The coldest I've run on regular cruisings is 15-degree F. Let the engine warm up for about 30-secs before loading it up.
 

Allen_Wrench

Resident Mad Scientist
Feb 6, 2010
2,784
26
36
Indianapolis
Been there, done that. As they said, tune it and it'll do fine. Last winter I think mine took maybe 10 or 20 seconds longer to get nice and warmed up. After that, she ran like always.