just wondering when shifting to a lower gear.using the engine as a brake to slow down is bad for the motor.im not saying from a too high rev but a moderate rev
engine brake
- Thread starter Antec1200X
- Start date
As long as you don't coast for a quarter mile with the throttle closed, you'll be fine. Engine braking isn't necessarily good for a 2-stroke, but it won't kill it as long as you get back on the throttle quickly.
Jist of engine braking..........try to avoid it at all costs as it loads up the engine. Not saying your engine will blow up if you do it from time to time, but you don't want to do it as it's just dumb to do as you are unnecessarily carrying RPMs that you don't need to be carrying and putting more wear and tear on the engine at higher RPMs than you need to when you could just pull the clutch in and solve the problem. Everybody engine brakes to an extent, but I try to avoid it whenever I can control it.
gotta think about this for a minute guys.....
while engine braking you are only using the pilot circuit (assuming the throttle is closed) so you're not putting much fuel into the cylinder vs. the RPM the engine is running at. this is going to run it pretty short on lube......and we all know what happens then
while engine braking you are only using the pilot circuit (assuming the throttle is closed) so you're not putting much fuel into the cylinder vs. the RPM the engine is running at. this is going to run it pretty short on lube......and we all know what happens then
lots of good info to keep in mind
i was thinking if u use the engine to brake too much,wouldnt that throw the crank/rod bearings out of wack? or timing
i was thinking if u use the engine to brake too much,wouldnt that throw the crank/rod bearings out of wack? or timing
Pre-mixed or auto lube its getting plenty of oil.
As long as you not over revving it will not hurt anything at all. Thats why the pilot circuit is always jetted richer then then rest of the circuits so when you close the throttle it actually loweres the EGTs and cools the engine.
As long as you not over revving it will not hurt anything at all. Thats why the pilot circuit is always jetted richer then then rest of the circuits so when you close the throttle it actually loweres the EGTs and cools the engine.
The problem is not jetting richer to cool the engine. It's the windage picking up the excess pool of oil laying in the bottom of the crankcase and pulling into the top end and burning it without enough being pulled in through the carb to replenish what's being burnt.
On the flip side to engine braking, you don't want to coast down from top speed with the clutch pulled in either. It will weld the ball to the clutch pushrod.
I try to do everything on the blaster in moderation. You don't want to hold the engine at high rpm and high speed for too long, when you let back off you'll lean it out and can mess it up. I don't want to engine brake for too long and run out of lubrication. I don't want to coast in neutral too long and mess up the clutch. Everything in moderation...
On the flip side to engine braking, you don't want to coast down from top speed with the clutch pulled in either. It will weld the ball to the clutch pushrod.
I try to do everything on the blaster in moderation. You don't want to hold the engine at high rpm and high speed for too long, when you let back off you'll lean it out and can mess it up. I don't want to engine brake for too long and run out of lubrication. I don't want to coast in neutral too long and mess up the clutch. Everything in moderation...
you should re-think you lubrication and jetting if your having isseus like that....
There is no pool of oil laying in the crank case when the engine is running where do you get that from?
PROPERLY JETTED, when you let off you dont lean it out... in fact you do the oposite, you richen it.
thats why when you set up your jetting you start with the main and work your way down. each circuit overlaps the next... making the one above it slightky richer... no fear of being to lean...
if your using a WB F/A meter or EGT you ALWAYS jet the lower circuits richer.
for instance if you main jet is running an EGT off 1050 degrees, at 1/2 throttle you want it 950 and at 1/4 throttle 850-900 and so on. If your lean on the lower circuits your going to blow the engine eventually.
welding the bearing to the push rods is a lack of lubrication or poor quality oil
Amsoil 75w-90 end of problem...
this stuff is designed to work in limited slip differentials for millions of miles in everything from race cars to tractor trailers. the lil blaster cant even begin to wear this oil out. ** if you want to you never need to change this oil, simply drain it, filter it through a coffee filter to remove any water an grit and re-use it for years*** it is just that good
Burning 2 stroke oil or oil breaking down at low combustion pressure or burning is a sign of an oil with a low flash point and poor film strength. (caster and petrol)
Again use a true synthetic engine oil at the proper ratio. If the engine is loading up and fouling plugs then your running to much oil, plain and simple
no extended high speeds.... what do guys like phragle do that race blasters in 24 hour endurance races?
I used to run mine 13 miles each way everyday on a groomed railroad bed flat out. with 22" tires, 14 40 gearing it would rip right along at 60mph all day long.
I used to average aprox 10,000 MILES a year on my Blaster. Riding it to work, running my trap lines, and riding to town to hang out with my friends. 95% of my riding was open gravel roads, paved roads and railroad beds stretching from Parry Sound to Huntsville.
sorry but thats about the most silly thing I have heard.....
There is no pool of oil laying in the crank case when the engine is running where do you get that from?
PROPERLY JETTED, when you let off you dont lean it out... in fact you do the oposite, you richen it.
thats why when you set up your jetting you start with the main and work your way down. each circuit overlaps the next... making the one above it slightky richer... no fear of being to lean...
if your using a WB F/A meter or EGT you ALWAYS jet the lower circuits richer.
for instance if you main jet is running an EGT off 1050 degrees, at 1/2 throttle you want it 950 and at 1/4 throttle 850-900 and so on. If your lean on the lower circuits your going to blow the engine eventually.
welding the bearing to the push rods is a lack of lubrication or poor quality oil
Amsoil 75w-90 end of problem...
this stuff is designed to work in limited slip differentials for millions of miles in everything from race cars to tractor trailers. the lil blaster cant even begin to wear this oil out. ** if you want to you never need to change this oil, simply drain it, filter it through a coffee filter to remove any water an grit and re-use it for years*** it is just that good
Burning 2 stroke oil or oil breaking down at low combustion pressure or burning is a sign of an oil with a low flash point and poor film strength. (caster and petrol)
Again use a true synthetic engine oil at the proper ratio. If the engine is loading up and fouling plugs then your running to much oil, plain and simple
no extended high speeds.... what do guys like phragle do that race blasters in 24 hour endurance races?
I used to run mine 13 miles each way everyday on a groomed railroad bed flat out. with 22" tires, 14 40 gearing it would rip right along at 60mph all day long.
I used to average aprox 10,000 MILES a year on my Blaster. Riding it to work, running my trap lines, and riding to town to hang out with my friends. 95% of my riding was open gravel roads, paved roads and railroad beds stretching from Parry Sound to Huntsville.
sorry but thats about the most silly thing I have heard.....
There is a film of oil that pools up more and sits in the crankcase. This tends to be most noticeable after the quads sit for a while and the oil resides down there and they smoke like all holy hell when you start them and you have to rev them after they are warmed up to blow some of it out of the system. Just a simple matter of gravity as to why it is there. This occurs on pistons as well, but almost all of it is expelled after the combustion process and exited. Over time, even the piston will get carbon deposits though. The crankcase doesn't have this luxury of combusting the remainder out. It's not like a 4 stroke where you have some sump of oil laying around....it's just a small layer of film that remains down there in most cases.
Oil separates from the fuel as soon as the fuel and air charge hits the crankcase. The oil falls out of suspension and flys around the crankcase. 99LRD, you are correct, it's usually a film coating everything and only pools after the engine has been shut down.
An oil film is required both on the bearings and the piston. Figure a mostly stock blaster has a RPM limit of about 7k which is a piston speed of ~2500 fps. If you are using the engine to do your braking, you are still turning the engine at high RPM's (guess 6K which is about 2,300 feet per second that piston is sliding over the surface of the cylinder).
Now think of a premix engine (we'll exclude autolube from the discussion because most eliminate the autolube) which is running off the different jetting circuits. The jets don't work by diameter so they are hard to compare directly but most of us have seen a pilot jet and a main jet. A main jet has a hole in it big enough to stick a pencil lead into (maybe .080" or maybe a little larger). A pilot jet has a hole in it you can barely stick a hair into (maybe .015"). Now if the lubrication your piston is relying on being replenished is trying to pass through those two holes, you're hurting to get enough lube through the pilot circuit if you are constantly letting your engine brake down from high rpm's.
I will agree that the pilot circuit is jetted richer (so cooler) than the other circuits but my concern with engine braking has less to do with cylinder temperatures and more to do with lacking lube.
I don't remember who it was (I think it was PaulieB but I'm not sure) that welded the ball to the rods. They pulled the clutch in at top speed and let it coast down to a reasonable speed. The clutch didn't work right again. Any metal can gaul given the proper amount of load (which is why the late model YZ250 engines used a thrust roller bearing instead of a ball between the rods) despite the type or quality of lube used. It has less to do with the type of transmission lube as the situation at hand. In the situation I've heard of, the ball may have had burrs on it and was just waiting for the right moment to go out but if you put even a perfectly smooth ball under enough load you can get it to weld to the shafts.
An oil film is required both on the bearings and the piston. Figure a mostly stock blaster has a RPM limit of about 7k which is a piston speed of ~2500 fps. If you are using the engine to do your braking, you are still turning the engine at high RPM's (guess 6K which is about 2,300 feet per second that piston is sliding over the surface of the cylinder).
Now think of a premix engine (we'll exclude autolube from the discussion because most eliminate the autolube) which is running off the different jetting circuits. The jets don't work by diameter so they are hard to compare directly but most of us have seen a pilot jet and a main jet. A main jet has a hole in it big enough to stick a pencil lead into (maybe .080" or maybe a little larger). A pilot jet has a hole in it you can barely stick a hair into (maybe .015"). Now if the lubrication your piston is relying on being replenished is trying to pass through those two holes, you're hurting to get enough lube through the pilot circuit if you are constantly letting your engine brake down from high rpm's.
I will agree that the pilot circuit is jetted richer (so cooler) than the other circuits but my concern with engine braking has less to do with cylinder temperatures and more to do with lacking lube.
I don't remember who it was (I think it was PaulieB but I'm not sure) that welded the ball to the rods. They pulled the clutch in at top speed and let it coast down to a reasonable speed. The clutch didn't work right again. Any metal can gaul given the proper amount of load (which is why the late model YZ250 engines used a thrust roller bearing instead of a ball between the rods) despite the type or quality of lube used. It has less to do with the type of transmission lube as the situation at hand. In the situation I've heard of, the ball may have had burrs on it and was just waiting for the right moment to go out but if you put even a perfectly smooth ball under enough load you can get it to weld to the shafts.
Lack of lubrication at more than an idle is a VERY good reason for the thrust washer to come out without the piston gouging. Running lean (or lacking oil) while under power will usually cause the piston to gouge the cylinder wall first because of the heat build up.
Running the engine at high RPM's without throttle (engine braking) doesn't generate the heat (as YFS101 pointed out the pilot circuit usually runs richer AFR's) but it still turns the same RPM's as though you are getting full fuel (and oil)
Running the engine at high RPM's without throttle (engine braking) doesn't generate the heat (as YFS101 pointed out the pilot circuit usually runs richer AFR's) but it still turns the same RPM's as though you are getting full fuel (and oil)
