so...uhm...what's the redline on these things?

[Anonymous]

shorter stroke is faster movement of piston,ifyou thinkabout it, longer stroke takes longerto travel at a given RPM than a shorter stroke, 4k RPM is alot for a stock engine, and definitelyin a car engine, 5500 or 6000 ios redlineon stock crank and rods in a car engine,

4k in a littlelightweigt engine has to be alot, its justplain racing big time at 4k, in 6thi can be 4k at 45 maybe 50 tops mph

thats plenty of rpm, i dontlike going over that,.

i wantto see actual suzuki RPM HP and torque curve bands,
youguys all have bigger engines, so maybe 4k doesnt sound liek engine is about to blow up inyours, butinmy 450it soundslike about too explode the bottom end, and no its not high miles and abused engine, i wantmy engine to last, unlike yours, mine has plenty of get up and go under 4k atall times,. you guys are nuts with a larger engine and saying 4k is way not enough,.,

crazy.... !

[terry]

125MPH @ 12000RPM, in third gear. (1100 Yoshimura pistons and stage 2 cams) It would have kept revving but I would have had to clean my undies with a shovel........

That was 18 months ago, bike still runs fine but the cops are like Iraqi snipers on my favourite roads, plus I'm getting older and scared-er, ha ha! :twisted:

[Anonymous]

You don't ever go faster than 50mph? Man, get it over with, sell your GS and buy a moped.

Ever seen one of these: http://www.conleyprecision.com/sohc.htm ?
How about 13,500RPM out of an engine with a displacement of just 3.5ci.

From http://www.suzukicycles.org/1980-1989/1981b.shtml :
GS450L: 43hp (31 kW)/ 9.000 rpm, 35 Nm (3,55 kg-m)/ 7.500 rpm.

[argonsagas]

Never over 4000RPM?

I have never bee on a GS 450, but others have given their top speeds/RPM's, and that suggests you must do only city driving, as you won't reach the speed limit on the highway at 4000RPM

My '82 Honda CM450 will run at 5000 until it runs out of gas, then, after a refill, it will do it again, and again. It has a redline of 9300....but (I have been told) that is where the redline "zone" starts...not where it ends.

I have also been told it has pretty high numbers for top speed, at really high RPM's, but I am not about to check that out.

[earlfor]

Quite the opposite. 4000 rpm in a short stroke engine is a slower piston speed than 4000 rpm in a long stroke engine. Some small two stroke alcohol/nitromethane powered engines rev as high as 30,000 rpm, but if you multiply their stroke by their rpm, you will find the piston speeds (in ft/sec)to be within normal limits. Also, pulling a high gear with the engine lugging at low rpm is much harder on the engine and will increase engine wear.

Earl

[quote="fast68"]shorter stroke is faster movement of piston,ifyou thinkabout it, longer stroke takes longerto travel at a given RPM than a shorter stroke, 4k RPM is alot for a stock engine, and definitelyin a car engine, 5500 or 6000 ios redlineon stock crank and rods in a car engine,

4k in a littlelightweigt engine has to be alot, its justplain racing big time at 4k, in 6thi can be 4k at 45 maybe 50 tops mph

[Anonymous]

shorter stroke is faster movement of piston,ifyou thinkabout it, longer stroke takes longerto travel at a given RPM than a shorter stroke

Rev limit your motor at any RPM you wish but, you are wrong on this. The shorter the stroke, the slower the piston speed.

[Anonymous]

Earl - you beat me to it!

[earlfor]

Must be the ol duck on a June bug affliction. :-) :-)

Earl

Earl - you beat me to it!

[Anonymous]

im not quite seeingh ow longer stroke at a given RPM makes faster piston movement than a shorter stroke engine at the sameRPM, theres something im not realizing today thats blocking how this can be,
my 450 i stoppedout at about 50,maybe 55 max, thats right on about 4200rpm, i tried it again today, thats all the engine sounds like it needs to go,its just plain screaming,i just cannot believe a stock 4 cycle engine can routinely go way more than 4k rpm ever andnot blow the bottom end out of it,

how can a little 4 cycle engine take so high of RPm so much and even remotely survive ?


where is the actual stock powerband on these things, and does it matter if its GS or not ? and if so then how ?

it screams for next gear at 4k, at max, i cant stand taking it much over 3k for next shift, its just plain screaming for next shift up way before 4k, i dont go over 50 max, sometimes i find it at 55, but that was only twice so far, oops

someone neeeds to find factory stock RPM vs. MPH info for the GS450 bikes, i need to know whats going on here. this bike is definitely not a highway bike at all, but is great in town, its fast enough acceleration for a 450, for sure

i cant see how constant high RPM is good for any 4 cycle engine, the car engine guys would cry opposite than you all are..
i cant see whats any different from one 4 cycle engine to another as far as normal and recommended RPM goes.


thanks

[Anonymous]

Envision a circle. The connecting rod big end will travel around this circle for each revolution of the crankshaft. The longer the stroke, the larger the diameter of the circle. With me so far? Now, if the circles diameter is increasing with stroke, then the distance around the circle is also increasing with stroke.

Now, RPM means revolution per minute (sorry, but I can't assume you know that given your previous posts). This means that the circle must be traversed in the same amount of time for a specific RPM.

If the distance around the circle is increasing with the stroke and the distance must be traversed in the same amount of time, then at any given RPM, the connecting rod big end must travel at a greater velocity around this circle to complete the circle.

Finally, since the piston is attached to the connecting rod, it too must travel at a higher velocity for a longer stroke engine at a specific RPM.

4k RPM's is nothing for a modern 4-stroke engine. I can't help what it 'sounds' like to you. Trust me on this.

[Anonymous]

ok i did some thinking for a minute or two just a second ago trying to get to sleep, and although a shorter stroke means less piston travel i dont yet see how or why it means any slower piston movement- travel and movement being two different things but related depending on certain things of course,
only way i can think of this all is by comparision to engines i know such as a chevy 327 or 307 in which both have same strokes, and then to the chevy 350 in which has longer stroke in which is same as the chevy 305 engine stroke. 327 engines were made to be a little higher revvers than a 350, but so also are 350 witha 400 crank, the 400 crank being longer stroke than a 350, of course.

i cant see how any change of stroke can mean that its safe to run the*@%^$*@%^$*@%^$*@%^$outofany engine,and that beingonlybecause the rod bearings still are around the journalsof a crankshaft,
a given higher rpm has to mean more wear at that given rpm than that occuringin an engine spinning at a lower RPM- at the rod bearings and even piston pin and crank mainn bearings also.

why run an engine at excessive RPM and therefore cause excessive wear ?


thats all im saying, i cant see that anyoneneeds to run these(450 engines at least) muchmore than even 3800 RPM, i cant see and have found noneed to run any higher than this on my 450

it doesnt lug or anything like that for me, i dont want it to and i dont, but i also dontover run it like it seems everyoneelsedoes ?
its running alot of RPM as it is just running it in town for fun.

now i will read the abovce reply just before this one and any others after my last reply,i had to make this reply before i forgot what i was gonna say, this info just came to me a minute ago, so,.,.



thanks

[Anonymous]

OKAY, It works like this. You measure in FPS, or Feet Per Second. Lets say our suzuki's have a 2.2 inch stroke, which my 1978 GS750E does. That's .18333333 feet. In each revolution, (The R in RPM) The piston moves up once and down once, or the piston travels .366666667 feet. My redline is 9000 RPM. Which means I am turning 150 Revolutions Per Second. This means that in 1 second, the piston has traveled a total of about 55 feet. Neglecting the strength of the wristpin, and expansion rates of the metal, or any safety margin that Suzuki may have incorporated, this is the point at which the piston will fuse to the sleeve, or tear the rod in two. Now lets look at a 2003 Honda CBR 600RR (a fast, modern bike). It has a stroke of about 1.7 inches, or .1416666667 feet. The piston moves .28333333334 feet per revolution. Lets pretend that 55 feet is the separation point for the CBR600RR too, like there was no advancement in metalergy or the strength of any internal part. This means that the bike can turn 194 revolutions per second, putting red line at 11647 RPM instead of 9000. And THAT is a simple way of what a red line is (CBR600RR Actually has a redline of 13500, due to stronger, shorter rods, stronger wristpins and a better alum alloy piston.) THAT is why a LONGER stroke means the piston moves FARTHER per Revolution. Go ahead, check my math.

[Anonymous]

Envision a circle. The connecting rod big end will travel around this circle for each revolution of the crankshaft. The longer the stroke, the larger the diameter of the circle. With me so far? Now, if the circles diameter is increasing with stroke, then the distance around the circle is also increasing with stroke.

Now, RPM means revolution per minute (sorry, but I can't assume you know that given your previous posts). This means that the circle must be traversed in the same amount of time for a specific RPM.

If the distance around the circle is increasing with the stroke and the distance must be traversed in the same amount of time, then at any given RPM, the connecting rod big end must travel at a greater velocity around this circle to complete the circle.

Finally, since the piston is attached to the connecting rod, it too must travel at a higher velocity for a longer stroke engine at a specific RPM.

4k RPM's is nothing for a modern 4-stroke engine. I can't help what it 'sounds' like to you. Trust me on this.

yes ive known what RPM technically stands for, no need to assume that i dont., ive been tearing down and have built and installed and run tons of GM engines for years now, motorbikes are something i have not known very well in the past,but i learn fast and willl earn this real quick like,


thanks

[Anonymous]

I give up. When you start talking about 327, 350, and 400 Chevy engines you are off on a tangent. You are basically confusing yourself with information that has no bearing on the subject.

I'm done on this topic. There is now way to convince you, that I am sure of. Sad part is, I don't care.

[Anonymous]

OKAY, It works like this. You measure in FPS, or Feet Per Second. Lets say our suzuki's have a 2.2 inch stroke, which my 1978 GS750E does. That's .18333333 feet. In each revolution, (The R in RPM) The piston moves up once and down once, or the piston travels .366666667 feet. My redline is 9000 RPM. Which means I am turning 150 Revolutions Per Second. This means that in 1 second, the piston has traveled a total of about 55 feet. Neglecting the strength of the wristpin, and expansion rates of the metal, or any safety margin that Suzuki may have incorporated, this is the point at which the piston will fuse to the sleeve, or tear the rod in two. Now lets look at a 2003 Honda CBR 600RR (a fast, modern bike). It has a stroke of about 1.7 inches, or .1416666667 feet. The piston moves .28333333334 feet per revolution. Lets pretend that 55 feet is the separation point for the CBR600RR too, like there was no advancement in metalergy or the strength of any internal part. This means that the bike can turn 194 revolutions per second, putting red line at 11647 RPM instead of 9000. And THAT is a simple way of what a red line is (CBR600RR Actually has a redline of 13500, due to stronger, shorter rods, stronger wristpins and a better alum alloy piston.) THAT is why a LONGER stroke means the piston moves FARTHER per Revolution. Go ahead, check my math.

yes i understand that longer stroke equals more travel of the piston, yes

im just stuckon how everyone seems to constantly run their bikes at or near redline, this is notgoodon engines in general, i cant see how anything over mid 4k or maybe 5k is not considered excessive in a 4 cycle engine ? is it only because its a motorcycle engine that it can take this abuse, am i too used to car 4 cycle engines,or ? if you run a car 4 cycle engine like you guys are running motorcycle 4 cycle engines well then you wouldnt have a running car engine for very long.

what makes motorbike engines thismuch abuse resistant ?
this would be the whole pointand question i have been trying to get at, and well is the point of the thread, basically, is it not?
it must have to do with FPS, but i need to work on that aspect and i need sleep right now,so..
i am more mechanically inclined than i may seem like and that you apparently assume, there is just something here i dont understand, and its to do with a whole new "breed" of engines and their safe capabilities,.


thanks!