Engine braking?

[rattlesnake_06]

I was jut reading on a different post about something else, when some one throws that you shoudnt engine brake. I use the engine alot to slow me down on hills and whenever. Am i harming this bike by doing so??

[Indawoods]

What post? I engine brake.... always have.

[jad628]

I was jut reading on a different post about something else, when some one throws that you shoudnt engine brake. I use the engine alot to slow me down on hills and whenever. Am i harming this bike by doing so??

Must be somebody with stock in a brake pad company.

[rbates9]

The only possible issue that could arise (that I can think of) is if you "engine brake" too fast for too long I could see how you might be able to run the cylinder dry due to the engine rpm's being high and the throttle closed not allowing the fuel oil mix to run in to the cylinder and lube every thing.
I also engine brake when I ride, not sure why but I picked up the habit of clutching or holding the throttle open a little. I'm not sure why I do either one but I do.

[scheckaet]

The only possible issue that could arise (that I can think of) is if you "engine brake" too fast for too long I could see how you might be able to run the cylinder dry due to the engine rpm's being high and the throttle closed not allowing the fuel oil mix to run in to the cylinder and lube every thing.

+1

[KDXrider1989]

I always engine brake, doesn't harm the bike at all. Only problem I can see with engine braking is if you downshift too soon, like rbates9 said

[Julien D]

Yep. It's recommended on long descents to keep the clutch pulled and give a little throttle once in a while to shoot some lube into the cylinder.

Also, if you had it pinned on a long stretch of open road, and then you slow up by shifting down through the gears, that can cause big problems. A little engine braking on a brief downhill is not going to destroy the engine though.

[OLHILLBILLY]

I usually pull the clutch in on downhills. 2 stroke doesn't have much for engine braking anyway, so to avoid any chances of the "no fuel/oil" problem, I've just gotten in the habit of free wheeling on some decel and most descending.

[Mr. Wibbens]

If there's no fuel/oil, how's the motor running?

[OLHILLBILLY]

If there's no fuel/oil, how's the motor running?

It's being, umm,, driven by input from the rear wheel.. Engine braking, that is the topic here.

[curtisa]

Not sure what postyou were reading, but if you're racing on say an MX track, you should n ever be coasting, you're either on the gas or on the brakes. If you're coasting you're a newby racer.

Yes, I have heard that you can harm a 2 ST on long downhills . . . the lube is mixed with the gas.

[Mr. Wibbens]

If there's no fuel/oil, how's the motor running?

It's being, umm,, driven by input from the rear wheel.. Engine braking, that is the topic here.

The motor is still running when you are engine breaking

Otherwise the rear wheel would be locked up no?

[Tedh98]

I usually pull the clutch in on downhills. 2 stroke doesn't have much for engine braking anyway, so to avoid any chances of the "no fuel/oil" problem, I've just gotten in the habit of free wheeling on some decel and most descending.

+1

[Tedh98]

If there's no fuel/oil, how's the motor running?

It's being, umm,, driven by input from the rear wheel.. Engine braking, that is the topic here.

The motor is still running when you are engine breaking

Otherwise the rear wheel would be locked up no?

If you wind out the engine to 9K rpm and then cut the throttle but don't pull in the clutch, the engine is spinning at 9K but only has enough fuel entering the engine to sustain idle, which shouldn't be enough to properly lubricate.

But when you pull in the clutch, the rpm's drop and the rpm's then better match the fuel entering the engine.

At least that is how I look at it.

[Mr. Wibbens]

It's being, umm,, driven by input from the rear wheel.. Engine braking, that is the topic here.

The motor is still running when you are engine breaking

Otherwise the rear wheel would be locked up no?

If you wind out the engine to 9K rpm and then cut the throttle but don't pull in the clutch, the engine is spinning at 9K but only has enough fuel entering the engine to sustain idle, which shouldn't be enough to properly lubricate.

But when you pull in the clutch, the rpm's drop and the rpm's then better match the fuel entering the engine.

At least that is how I look at it.

Thats a little more extreme than typical engine braking dontcha think?

[Tedh98]

Sure, most of the time my 9K example is extreme. But what is typical?

But if you get going downhill in the wrong gear you get the rpm's up pretty quickly.

One of the places we go riding has a drag strip, I hear a lot of guys wind up through the gears and then hear them chop the throttle and engine brake down to 10 mph. My son had the nasty habit of doing this when he first started riding.

I guess the problem really becomes how many rpm's and for how long can a motor spin beyond a given level of fuel before the oil can't provide protection?

[OLHILLBILLY]

The motor is still running when you are engine breaking

Otherwise the rear wheel would be locked up no?

If you wind out the engine to 9K rpm and then cut the throttle but don't pull in the clutch, the engine is spinning at 9K but only has enough fuel entering the engine to sustain idle, which shouldn't be enough to properly lubricate.

But when you pull in the clutch, the rpm's drop and the rpm's then better match the fuel entering the engine.

At least that is how I look at it.

Thats a little more extreme than typical engine braking dontcha think?

Anytime the throttle is closed and the engine is turning above idle RPM, there is "insufficient" (that's probably the word I should have used instead of "no") fuel/oil coming into the motor to lubricate the bottom end at that rate of motion. There is enough residual oil on the bearings to last for a period of time. How long that period of time is, is what your comfortable with.
Kinda like the 60:1 mix folks, if your comfortable with it, hey.. it's yours.

[Mr. Wibbens]

I've never worried about it yet, and we actually have hills to ride down here

[SS109]

I read some where, can't remember where, a 2T engine holds oil in the lower part of the crankcase that has fallen out of suspension. That oil is then "splashed" onto the crank bearings and even up to the piston pin. So, oil in suspension is not the only lubrication the bottom end receives.

[rbates9]

I read some where, can't remember where, a 2T engine holds oil in the lower part of the crankcase that has fallen out of suspension. That oil is then "splashed" onto the crank bearings and even up to the piston pin. So, oil in suspension is not the only lubrication the bottom end receives.

I have not heard that, not that I'm arguing that. But say you are going down a very long down hill, how long would that oil stay in there?
I belive that this is one of those personal preference type things. Could it hurt your engine? Yes. Will it destroy your engine the first time? No. I would have to say that it greatly depends on how long, how fast the engine is turning and what the oil mix is.