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

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! :lol:

 

[earlfor]

Must be the ol duck on a June bug affliction.

Earl

Earl - you beat me to it! :lol:

 

[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 thepissoutofany 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!

 

[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.

no, i am not on a tangent, you assume that i am, but that is a false assumption,i am trying to make a comparison in order to understand how these motorcycleengines can take the higher RPM abuse.,

now i do know you dont care, you should have just told me in your first response. i think that you give up easy,or just dont have much of a temper,


thanks
though,

 

[AOD]

there's a really simple way to look at this. heck i'm a mechanical engineer, and i rather have it simple sometimes. general rule of thumb, the smaller an engine, the higher it can rev. simple as that.

now when you're comparing a GS450 vs a GS550, you have two more cylinders in the mix, and the size of the 550 cylinders is quite smaller. that being said the 550 should be able to rev a bit higher then a 450.

4000 RPM and no higher...wow.

my 79 550 makes no power below 4000 RPM. i shift into a higher gear as soon as i i hit 4000 RPM if i have to slow down. i sometimes ride it out from 2-4000 RPM, but its quite bogged down. that is the result of pod filters and 4-1 exhaust, but once i hit 4000 RPM the engine takes off.

how can these engines take more then 4000 RPM? pretty simple answer. small valvetrain, and over-head cam setup. 4000 RPM is high for most cars of the past, yes. but that's because they were pushrod engines. the 1970's DOHC technology on our bike engines is the current standard of engines today!! the small engines are made to rev higher and handle it just fine. i've driven my 78 550 on the highway at 7000 RPM for over an hour...no problems whatsoever.

when i'm cruising around town...i like 5000 RPM on my tach.

~Adam

 

[AOD]

fast, i hope that i explained enough why the engines can handle more revs.

honestly if suzuki wouldn't want you to rev that high, they'd set the redline to 5000. the basic idea behind the small inline engine is high-revving power. its the exact opposite of a big v-twin pushrod engine, low-revving torque power.

my Ford shifts at 4200 RPM - but its a pushrod V8 - that is expected.

when you move the cam up on top of the engine, you have a lot less moving parts and distance to cover in the valve train. this equates to more power and higher revving capabilities.

take your bike out once, on a clear road from a stop. ride the clutch out at 3000 RPM and go full throttle till 8000 RPM, clutch, and sink it into 2nd and take it up to 8000 RPM again. your bike will shift like glass, smoother then you've ever felt. and you'll probably have a big grin on your face.

~Adam

 

[Hap Call]

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!

Okay, my turn to take a swing at this! Honestly Fast, I am still not convinced that you're not pulling our collective leg but what the hey...There are two basic reasons why a motorcycle engine can rev higher than a car engine. One is that the mass of the car engine pistons and rod assemblies are MUCH greater than a motorcycle thus forces produced are much greater. Second, due to the mass inherent to a push rod valve assembly, valve train separation (different parts losing contact with each other) increases and thus the chance for valve collision with the piston increases.

4000 RPM is too slow. If you want to keep you engine below 4000, that is fine, but I advise you to stay off any highways, interstate freeways, and any place that requires you to accelerate to stay out of harms way.


Hap

Hap

 

[moto_dan]

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!

Okay, my turn to take a swing at this! Honestly Fast, I am still not convinced that you're not pulling our collective leg but what the hey...

I think we've been baited. Wheres Dom?????????

 

[Anonymous]

there's a really simple way to look at this. heck i'm a mechanical engineer, and i rather have it simple sometimes. general rule of thumb, the smaller an engine, the higher it can rev. simple as that.

now when you're comparing a GS450 vs a GS550, you have two more cylinders in the mix, and the size of the 550 cylinders is quite smaller. that being said the 550 should be able to rev a bit higher then a 450.

4000 RPM and no higher...wow.

my 79 550 makes no power below 4000 RPM. i shift into a higher gear as soon as i i hit 4000 RPM if i have to slow down. i sometimes ride it out from 2-4000 RPM, but its quite bogged down. that is the result of pod filters and 4-1 exhaust, but once i hit 4000 RPM the engine takes off.

how can these engines take more then 4000 RPM? pretty simple answer. small valvetrain, and over-head cam setup. 4000 RPM is high for most cars of the past, yes. but that's because they were pushrod engines. the 1970's DOHC technology on our bike engines is the current standard of engines today!! the small engines are made to rev higher and handle it just fine. i've driven my 78 550 on the highway at 7000 RPM for over an hour...no problems whatsoever.

when i'm cruising around town...i like 5000 RPM on my tach.

~Adam

awesome!
now we are really gettingn somewher,e yes simplicity is sometimes the best, sometijmes, like right now, so now i feel better after your responses, i thought no one here was understanding where i am coming from and how i am feeling in regards to this subject, at least you and about only one other person seem to understand what i mean really.
so techniclaly it is because of the smaller cylinder bores AND because of the OHC design, ok, now i see.

its just crazy in my mind that an engine thats not 2 cycle can take and handle so much RPM, i suppose that i will need to try this 450 out at a higher RPM band

can anyone agree with higher RPM not being good overall? or does it depend on how often you run higher RPM- with these bike engines* ?

thanks

 

[Anonymous]

hap and moto, ok i see where you two really stand...
i dont even know why you two replied to this, since you two dont believe, you know,...
i amnot joking here,i really was not seeing how or why any 4 cycle engine could run so freaking fast and not go kaboom !!! but i am getting there... slowly.... even though its really crazy, my 450 sounds like its going 9k at 4k, im just afraid to go past that 4k... or kaboom ! and i guarantee that if i do run it over 4k all the time- like you guys are all saying is ok to do- then everyone i ride with or ride by will say damn you run that way high RPM.
because.. well.. thats what it sounds like !


so basically super high RPM is way better than lower, more normal RPM- even if at the lower RPM that sounds better for the engine- that i run mine at- doesnt lug or chug or anything like that for me ?
pretty crazy..
then whats the point of 2 cycle engines then ?
the RPM you can run them at constantly seems like about the same as what you guys are running your 4 cycle engines at.


thanks for trying and making false assumptions regarding myself and this thread, how about i go and make false assumptions about you ? would you like that ??

.......

i thank those ofyou who are taking time to understand and explain to me this RPM phenomenom

 

[bgmart450]

I run my 450 on the freeway at 6-7k regularly. I rev to 8-9k on fun little bursts. I think the occaisional missing of the 1-2 and sometimes the 5-6 ( I really need to look into that one)......well I don't even want to speculate where the needle falls... I have owned the bike for a little over a year and it had 22k on it when I got it.

I have experienced no issues relating to reving the engine over 4k. I used to keep it under 4-5k, and still do when I want to be quiet (its LOUD), but I couldn't even imagine NEVER taking it any higher. I am with everyone else, they built these with the intention of using everything up to the redline. With as many as we have just here on this site still on the road should somewhat attest to the superior engineering of Suzuki.

Rev it up... you'll enjoy it (and your bike really won't hate you for it either)

 

[Anonymous]

I run my 450 on the freeway at 6-7k regularly. I rev to 8-9k on fun little bursts. I think the occaisional missing of the 1-2 and sometimes the 5-6 ( I really need to look into that one)......well I don't even want to speculate where the needle falls... I have owned the bike for a little over a year and it had 22k on it when I got it.

I have experienced no issues relating to reving the engine over 4k. I used to keep it under 4-5k, and still do when I want to be quiet (its LOUD), but I couldn't even imagine NEVER taking it any higher. I am with everyone else, they built these with the intention of using everything up to the redline. With as many as we have just here on this site still on the road should somewhat attest to the superior engineering of Suzuki.

Rev it up... you'll enjoy it (and your bike really won't hate you for it either)

i hope that it wont hate me for it, that would be a b*tch ! but damn i bet its insanely fun, its already fun enough as being a 22k miles 450 but damn thats at 4k rpm and under, man.. what about upto 9.5K ?? insane!@
why would anyone need anythingover this largeof abike then ?
its frickin fast enough get upand go as it is how i even drive it!

wild....

thanks

 

[lhanscom]

It also helps to 'Clean the carbon out' when you rev it up. Yeah, that's why I do it. :roll: :lol: