Paranoid with 2T

[1gr8bldr]

How do most do it? I am paranoid about descending a hill without the clutch pulled in. Even for short distances, I always pull the clutch with the 2T, worried that the motor is working without fuel/oil. I noticed in a video, a particular rider who seemed to bump the throttle every second and seemed to be engine braking?? I wonder if I am right on or overly paranoid? Sometimes I miss my 4T here, no worries. 

[Singletrack_rider]

 Shift up a gear or 2  . Treat the hill like any other section of the trail. or twist the throttle and go faster . 

[1gr8bldr]

8 minutes ago, GreenMT_Rider said:

 Shift up a gear or 2  . Treat the hill like any other section of the trail. or twist the throttle and go faster . 

I should clarify, we ride for fun, never raced. Often the downhill pace is set by the riders in front, or like this week, had to go slow waiting for the wife to keep up. 

Edited April 13, 2017 by 1gr8bldr

[David C]

How do most do it? I am paranoid about descending a hill without the clutch pulled in. Even for short distances, I always pull the clutch with the 2T, worried that the motor is working without fuel/oil. I noticed in a video, a particular rider who seemed to bump the throttle every second and seemed to be engine braking?? I wonder if I am right on or overly paranoid? Sometimes I miss my 4T here, no worries. 

How could it be running, even with the clutch in, and not getting any fuel?

[TheKX500boi]

1 hour ago, 1gr8bldr said:

How do most do it? I am paranoid about descending a hill without the clutch pulled in. Even for short distances, I always pull the clutch with the 2T, worried that the motor is working without fuel/oil. I noticed in a video, a particular rider who seemed to bump the throttle every second and seemed to be engine braking? ? I wonder if I am right on or overly paranoid? Sometimes I miss my 4T here, no worries. 

Holding your clutch in like that wears it out. And if its revving really high just shift up. And even at idle the bike is still sucking in fuel ( so oil as well ). And since you're not "accelerating" there is not really any load on the motor. I dont think twice riding down on my two stroke and not pulling in the clutch. 

[EmpireofDerp]

The only way to know if you're &%$#@!ing it up is to try and &%$#@! it up.

[RawbW]

I usually just go up a gear or two, if I'm going for speed I'm on the gas anyway,  but I know people who don't care as long as it ain't overrevving  they don't care.i don't worry too much about it, it would take a long descent with high rpm closed throttle for that to come into effect, honestly just go up a gear or two if your worried.

[1gr8bldr]

So, most of you engine brake in a higher gear??? Is it still called engine braking even if your not slowing? This is my first 2T. 

[The Spanky]

The oil film that is coating all of the engine parts doesn't just suddenly disappear as soon as you start down a hill. The engine is also under zero load in that situation. Stop worrying about it, you aren't going to hurt anything by going downhill with the throttle closed.

Edited April 13, 2017 by The Spanky

[1gr8bldr]

1 hour ago, The Spanky said:

The oil film that is coating all of the engine parts doesn't just suddenly disappear as soon as you start down a hill. The engine is also under zero load in that situation. Stop worrying about it, you aren't going to hurt anything by going downhill with the throttle closed.

So.. ok to just ride it like you would a 4T??

[Bron-Yr-Aur]

Imo it is something I keep in the back of my mind. The bike goes lean with the throttle closed and the rpms staying high. But a 2t is useless with engine braking anyways. So I usually pull the clutch and ride the brakes. A lot easier to replace pads, and rotors for that matter, than a top end. Maybe I'm over thinking it, but at least I'm happy ?

[The Spanky]

 

So.. ok to just ride it like you would a 4T??

Well no, you don't ride a two-stroke like a four-stroke LOL...

 

But as far as situations like the OP is asking about, yes. Coasting a two-stroke with closed throttle isn't going to harm it. When there's no airflow through a two-stroke, there's also virtually no oil migration. The oil that's already on the parts stays there. And no load means no heat production, so you're not causing a thermal overload to the piston that could result in a seizure.

I suppose if you coasted all the way down Pikes Peak, in theory the rings would eventually scrape enough oil from the cylinder to do damage, but in the real world...

[The Spanky]

 

The bike goes lean with the throttle closed and the rpms staying high.

Irrelevant, as their's no load on the engine, therefore no heat production. Lean mixtures during large-throttle high-load situations are bad because there's not enough fuel to keep the piston crown from overheating. But there's zero load while coasting.

[Truman Sparks]

 On Two stroke cars like the Saab And Trabant, top gear is free wheeling, this prevents going down a long hill at 60mph and starving the engine of oil.

 That said on a Two Stroke bike just blip the throttle every 30 seconds or so while descending the hill. 

Not sure what ratio you are mixing at but my IT510 is mixed at the factory ratio of 20-1.

[temporarily_locked]

I was sure it wouldn't seize back when I was on two stroked and purposely tried to get it too. It never did and I've never heard of it happening in practice. You don't have to worry about it.

[1gr8bldr]

 

 On Two stroke cars like the Saab And Trabant, top gear is free wheeling, this prevents going down a long hill at 60mph and starving the engine of oil.

 That said on a Two Stroke bike just blip the throttle every 30 seconds or so while descending the hill. 

Not sure what ratio you are mixing at but my IT510 is mixed at the factory ratio of 20-1.

My Freeride is 80:1, not sure if this makes it more likely or less likely.

[1gr8bldr]

OK, then, I sure will enjoy not pulling the clutch every time I coast. I will likely blip the throttle as I mentioned in the video that  I saw. I will also try gearing up on the longer downhill coasts. Will make the 2T more enjoyable, LOL, was seemingly a lot more work trying to do this so much. 

[ossagp]

On 4/12/2017 at 6:14 PM, 1gr8bldr said:

How do most do it? I am paranoid about descending a hill without the clutch pulled in. Even for short distances, I always pull the clutch with the 2T, worried that the motor is working without fuel/oil. I noticed in a video, a particular rider who seemed to bump the throttle every second and seemed to be engine braking? ? I wonder if I am right on or overly paranoid? Sometimes I miss my 4T here, no worries. 

There is a misconception about what happens when you roll down a hill throttle off.  Some say it goes lean.   No.  To "go lean" you need some air.  Quite a bit.  Roll down the hill and when you get to the bottom (throttle off all the way) apply the brake and kill your bike.  You probably will find that the plug is pretty darned moist.  Not the sign that it was lean.  You create the highest vacuum the engine will ever see.  That pulls very hard on the low speed jetting.  No much combustion heat is being produced so very little of the oil is being burned,  and with flow greatly restricted not much is being blown out.  That is why long downhills will flood or "load" your bike up.   This myth seems to follow the "my bike went lean when I turned the throttle off at the end of the sandwash" fable.  

Edited April 14, 2017 by ossagp
correct misspelling

[mx4god]

There is a misconception about what happens when you roll down a hill throttle off.  Some say it goes lean.   No.  To "go lean" you need some air.  Quite a bit.  Roll down the hill and when you get to the bottom (throttle off all the way) apply the break and kill your bike.  You probably will find that the plug is pretty darned moist.  Not the sign that it was lean.  You create the highest vacuum the engine will ever see.  That pulls very hard on the low speed jetting.  No much combustion heat is being produced so very little of the oil is being burned,  and with flow greatly restricted not much is being blown out.  That is why long downhills will flood or "load" your bike up.   This myth seems to follow the "my bike went lean when I turned the throttle off at the end of the sandwash" fable.  

I have found this to be accurate. I would consider my ktm 200 to be jetted well as it has crisp throttle response at virtually every RPM and throttle opening. And yet, the only time I really find myself pulling in the clutch on downhills is when I need to "clear it out" because the RPM starts to drop on a long descent because I have it in a higher gear at a low RPM.

 

 

Edited April 13, 2017 by mx4god
spelling error

[ossagp]

It doesn't tell you exactly what the combustion chamber is doing,  but if you put a temp gauge on you can see what your coolant is doing.   Lots of us were around when there was a proliferation of road bikes that were two stroke.   The oil injected versions shut the oil off to what would have been 80-100 to one.  Even on the old oils we NEVER saw one of our triples come back to the shop because of seizure or bearing failures.  Cuesta grade was pretty long and steep,  and right out the front door so to speak.   

I was around two saab two strokes and never realized they freewheeled,  but it seems REALLY counter intuitive that they would freewheel in high when rpms would be on the lower side but allow you to keep the car in a LOWER gear at a higher rpm.  I am not doubting the freewheeling,  but wonder about the reason.  I can think of at least two where it might be advantageous enough in high only.  

Edited April 13, 2017 by ossagp
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