View Full Version : Friction Zone in the Cold


Sykes92
December 15th, 2013, 03:28 PM
Is the friction zone supposed to be very weak in cold climates?

Unless, I have the choke on, my bike struggles a lot to not stall when playing with the friction zone. With choke on, bike feels like what I'd expect it to.
Is this normal or is it a possibility my bike is too lean?

This is in 30°-45°F weather.

csmith12
December 15th, 2013, 06:27 PM
Hmmm.... Some riders change the tune of their bikes for cold weather, high altitude and other reasons. The 250 is lean in stock form. If your bike don't like the cold, you may have to richen the mix for it to be happy.

Assuming everything is right with the tune.
What happens to oil when it gets cold? As a rider, you can be sensitive to the feel of such things. Just takes a bit more throttle to not stall or use a thinner weight oil in cold weather.

Also, the friction zone is pretty small anyway. It could be just your first time around in the cold. Don't change anything until your sure there is really a problem with the machine. Use this chance to get a good feel for how the friction zone really feels as the weather changes and go from there. Also, be mindful that the friction zone can vary between bikes, even of the same model.

Motofool
December 15th, 2013, 09:08 PM
Is the friction zone supposed to be very weak in cold climates?

Unless, I have the choke on, my bike struggles a lot to not stall when playing with the friction zone. With choke on, bike feels like what I'd expect it to.
Is this normal or is it a possibility my bike is too lean?

This is in 30°-45°F weather.

If this only happens when the engine is cold, everything is fine, just use the choke until the engine has reached normal temperature, which should happen about 3 miles of normal riding at those temperatures.

If this happens even after the engine is warmed up, then your mix may be too lean for those temperatures and higher density of the air (not enough flow of fuel through the jets to mix with so many molecules in the aspired air).

Sykes92
December 15th, 2013, 09:23 PM
This is even after she is warmed up. I may downshift to enter my driveway and only use the clutch to navigate to my backyard and it struggles to pull the bike along. I can feel where my friction zone is, because with the choke it will actually pull the bike without throttle, like I had assumed the friction zone should've. I feel maybe the bike is running lean going off of what you guys have said. Things like weak throttle response and low idle RPM fix themselves once the bike is warmed up, but the friction zone still barely pulls. Which I want to practice slow maneuvers without throttle, just to master the friction zone. So I may see about making it richer. So quick question: I found the snorkel that was removed by the OG owner of my bike. Should I reinsert it, or rejet the bike to account for its removal? I know which one is probably easier, but I'm curious as to what will be better down the road. Does my bike actually gain that much without a snorkel?

corksil
December 15th, 2013, 10:49 PM
Being a 250, I don't think you will be gaining much real power by re-jetting. But it seems to be a well-documented fact that you should not remove the snorkel without doing simultaneous work to richen the mixture.

As stated, these bikes seem to run lean atleast during midrange acceleration, which would be exacerbated by removing the snorkel, increasing airflow/oxygen content. I'm not sure how things would be affected around idle, but I've read that midrange AFR can be dangerously lean -- so it's not a stretch to assume that idle could be moderately affected by snorkel removal.

As for clutch friction zones, I notice that my clutch is a little more 'grabby' further out on the lever when the bike is quite hot after a brutal ride.

When riding around normally/cold, the clutch seems to grab sooner with less "out" on the lever, but after beating the bike around and really getting things hot, the clutch seems to grab a little more sharply, further 'out' on the lever.

Hopefully this helps.

Boom King
December 15th, 2013, 11:42 PM
When riding around normally/cold, the clutch seems to grab sooner with less "out" on the lever, but after beating the bike around and really getting things hot, the clutch seems to grab a little more sharply, further 'out' on the lever.

The clutch can expand with heat if you're really beating on it which means more free play at the lever. Check your clutch cable and freeplay.

Note to self, I need to do this in the spring.

Sykes92
December 16th, 2013, 06:09 PM
I'm going to try adjusting my idle speed and see if that helps get the bike to move without throttle with choke off and after being warmed up. If not, I'll try looking adding or removing a washer from the carb. I was told the bike had its carb shimmed, but no mention of the amount of washers.