Is there a red line (max RPM)

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Kenora

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My 97 VMAX 600 XTC (twin) runs wide open at about 8000 RPM... I don't see a red line on the tach though, whats the max recommended RPM (red line)...
 
Engine designers work around max piston speed when designing engines bore and strokes,
The average safe piston speed is considered to be 3500 ft/min with the max being 4000 ft/min[this is for run of the mill engines...not exotic designs]

Your 97 600 SX has a stroke of 68mm which is approx 2.68"
at 8000rpm your piston speed would be :
[2.68 + 2.68] x 8000 /12
42880/12 = 3573 ft/min
so 8000 would be pretty safe but over the 3500 ft/min

9000 rpm would be approx 4000 ft/min the absolute max!

Notice Yamaha specs 7800 RPM as target RPM...under the 3500 ft/min
 
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Kenora said:
I'll treat that as the red line then, thanks.... funny they don't mark it on the instrument though
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Unlike a vehicle with a transmission that uses an array of gears for torque multiplication, your sled has a CVT, or Continuously Varible Transmission. The clutch parts (weights, springs, helix) and overall design dictate peak rpm, not the rider shift points.

There is no need for a warning (redline) to the rider on a sled if the CVT is functioning properly. Since the rider has no active control over upshifts or downshifts, the tach is only used to ensure you aren't above or below the recommended peak torque RPM at WOT.

Find a copy of Olav Aaen's clutch tuning handbook. You'll get a better understanding of how the CVT works. If you're like me, you'll need to read it a dozen times or so but it's a good read.
 
I think a good measure if it goes past 9000 rpm and it isint made to back off or wait for the gut wrenching ka-BOOM!!! :o|
 
nelsonhouse said:
whats the math on the red head
Click to expand...

600 + 700 SX have a 59.6mm[2.346"] stroke

[2.346 + 2.346] x 8500 rpm/12
4.692 x 8500/12
=3334 ft/min

so the 600 + 700 SX tripples are plenty safe at the recommended 8500 RPM

9000 RPM on these engines is still only 3519 ft/min piston speed

This is one reason manufacturers went to multi cylinder short stroke engines so they could run more RPM safely and pump more air...more air more HP.

Back in the day Honda had 6 cylinder 250cc gp bikes that had a very short stroke and tiny pistons and multi valve cylinders for very high rpms...that is the engine design that the 1979 Honda CBX 1050cc six cylinder street bike was hatched from.
 
bluemonster1 said:
take a marker and draw a line on the tach face where you figure red line is..simple as that..
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Or do what a lot of us do and twist your tach so that your desired shift-out rpm (7800) is at the 12 o'clock position and also mark it if you like.

For me - it's been easier to see if the needle is pointing straight up at speed than trying to see if it corrisponds to the rpm I'm shooting for.

Actually, I use the memory feature on my Digitron after each pass and concentrate on keeping the shinny side up during.
 
snomofo said:
Or do what a lot of us do and twist your tach so that your desired shift-out rpm (7800) is at the 12 o'clock position and also mark it if you like.

For me - it's been easier to see if the needle is pointing straight up at speed than trying to see if it corrisponds to the rpm I'm shooting for.

Actually, I use the memory feature on my Digitron after each pass and concentrate on keeping the shinny side up during.
Click to expand...
that is a good idea actually rotating the tach for easier viewing... ;)!
 
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