700 VES max RPM? - Snowmobile Forum: Your #1 Snowmobile Forum

Jimboat · 12-31-2012, 08:11 AM

What should my 2004 700 VES (Edge Classic) engine turn at top RPM? I am getting about 8000RPM. is that about right?

guitarman69 · 12-31-2012, 01:53 PM

8200 should be your max,

Jimboat · 12-31-2012, 02:40 PM

Quote:

Originally Posted by guitarman69

8200 should be your max,

thanks, guitarman69. it sounds like we're in the right range. do you know if the engine has a limiter to 8200 RPM or does it just self-govern to a max of 8200? (ie - what happens at 8200? Do i need to be sure to keep RPM below the max? or will the engine keep be in safe RPM?)

thanks for your advice!

**BC_Dan** · 12-31-2012, 05:57 PM

The flyweights set the maximum RPM of the engine. You use the weights needed to achieve the RPM required. The max RPM is near the peak torque value for the engine and usually just past the peak HP. If you were to go to 8300, there won't be any damage to the engine, but HP will be off significantly. 2-stroke engine HP and torque drop like a rock once the max. numbers are reached, there's no advantage to increasing RPM past the maximums.

Greatly increasing RPM, such as to 9000, will prematurely wear the engine and can cause engine damage. Unless other modifications to the engine are done to move the peak HP and torque, stick with the factory numbers.

Jimboat · 01-01-2013, 08:31 AM

Quote:

Originally Posted by BC_Dan

The flyweights set the maximum RPM of the engine. You use the weights needed to achieve the RPM required. The max RPM is near the peak torque value for the engine and usually just past the peak HP.

thanks BC_Dan.

Brummo · 01-01-2013, 09:33 AM

I'm always worried about running max RPM's. Should I be? It's the "red line" that scares me, I mean, red is bad...

Jimboat · 01-01-2013, 09:40 AM

Quote:

Originally Posted by Brummo

I'm always worried about running max RPM's. Should I be? It's the "red line" that scares me, I mean, red is bad...

i have the same worries, Brummo. that was the exact reason for my question. i wanted to know if i had to watch my tach closely when i am in that "redline" region, or whether the engine would simply prevent itself from over-reving!

i wondered what i would "notice" or "feel" wrt performance if i got to or 'past' the 'redline'?

Brummo · 01-01-2013, 10:41 AM

I mean we have DET built in to help prevent the motor from things happening to it but things can still go wrong at 8200 RPM.

**BC_Dan** · 01-01-2013, 11:09 AM

When you are at WOT, the theory is to set up the primary to give you near max. torque and HP. The primary will allow the engine to spin to that RPM and then stay there as the secondary senses the torque and shifts to higher gear ratios. Certainly, there will be more wear at WOT than at medium RPM, but the engine doesn't come apart like a 4-stroke. There's no danger in it coming apart if it hits the theoretical "red line" every time you run it. Mountain riders do that often, it's how you keep the sled going forward on the steep stuff and in the powder. And there really aren't many moving parts in a 2-stroke, there's no valve train and valves to get sucked in. It's easy to turn 10k, but not useful if the power drops off at 8k. You usually aren't at the max. RPM for very long, on the flats you will be going way too fast if you pin it and hold it and in the mountains, you run out of hill eventually and have to stop at the top or turn out (or get stuck!!

)

Brummo · 01-01-2013, 12:00 PM

I understand that. Makes sense, but freaks me out.. LOL

Jimboat · 01-01-2013, 03:24 PM

Quote:

Originally Posted by BC_Dan

When you are at WOT, the theory is to set up the primary to give you near max. torque and HP. The primary will allow the engine to spin to that RPM and then stay there as the secondary senses the torque and shifts to higher gear ratios. Certainly, there will be more wear at WOT than at medium RPM, but the engine doesn't come apart like a 4-stroke. There's no danger in it coming apart if it hits the theoretical "red line" every time you run it. Mountain riders do that often, it's how you keep the sled going forward on the steep stuff and in the powder. And there really aren't many moving parts in a 2-stroke, there's no valve train and valves to get sucked in. It's easy to turn 10k, but not useful if the power drops off at 8k. You usually aren't at the max. RPM for very long, on the flats you will be going way too fast if you pin it and hold it and in the mountains, you run out of hill eventually and have to stop at the top or turn out (or get stuck!!

)

thanks for your great explanations, Dan!

So, if i were to just "pin" the throttle and let the engine go all the way up to as much RPM as it wanted to go to (gives me the willies just thinking about it!), then what sensation or what response would my engine give me as it gets to max RPM? or above?

**BC_Dan** · 01-01-2013, 04:26 PM

The weights set the max running RPM. Once that RPM is reached, RPM doesn't go higher. If you were to pin it with no-load, RPM may climb higher, that would not be wise. So if you pin it under load, the clutches shift out until there's no more HP to drive the sled faster. RPM remains the same with speed being variable; if you were to hit some deep powder or a steep spot, the RPM stays the same but the secondary senses greater torque on the track so the clutches shift to a lower ratio. On a long pull on smooth snow or ice, the RPM may climb a bit over the intended RPM, but not by much.

Most 2-strokes have a very narrow power band, with some sleds only having max. HP/torque for about 200 RPM so it's important to keep the RPM in the powerband. Some of the newer engines have a much greater powerband and will pull harder for longer but are still limited by the clutching.

**RJ Gleason** · 01-01-2013, 05:15 PM

When both units are balanced properly, the engine will never exceed peak rpm by more that 200 and will always drop back and maintain the desired peak.
The preload of the spring and the angle of the helix in the secondary will determine how fast it achieves that peak and how well it holds with out backshifting under load.

rbrumm · 01-02-2013, 08:19 PM

So other than the speed, I should not be too worried about WOT once in a while.

joshkidner · 01-03-2013, 12:54 AM

exactly. i mean i still wouldnt suggest WOT even on straight shots for long periods without letting it rest a little, but holding it down for some seconds for that rush of speed or to get up a hill wont hurt.