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Offline ashpeat

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2 Stroke Rev Limits
« on: January 26, 2013, 04:20:25 PM »
Ok so i was wondering exactly how far can you rev your 2 stroke, i know they dont have rev limiters as such, to what point can you keep the throttle on full before you need to change up a gear?

I find i probably change gear way to early cos im conscious of blowing the engine (if thts possible), just after its been in the powerband for a few seconds, i know this is not right as when you listen to pros riding two strokes they maintain that really high revving sound, and you cant even really tell when they have changed gear, its like a continious noise.

So at what point do you all change gear, ive heard of people saying a technically sound engine can rev up to 20,000 rpm. what are your thoughts?
« Last Edit: December 31, 1969, 04:00:00 PM by ' »

Offline _X_

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2 Stroke Rev Limits
« Reply #1 on: January 26, 2013, 04:26:42 PM »
you shift just before it falls off the pipe, if it keeps pulling to your braking point no worries. but you should feel when it runs itself out power, it will just stop pulling and flatten out(just make noise).
« Last Edit: December 31, 1969, 04:00:00 PM by ' »

Offline ashpeat

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2 Stroke Rev Limits
« Reply #2 on: January 26, 2013, 04:31:00 PM »
you shift just before it falls off the pipe, if it keeps pulling to your braking point no worries. but you should feel when it runs itself out power, it will just stop pulling and flatten out(just make noise).

ok so what your saying is don't worry about it, as long as it theres no risk of damaging it i think thats the best option as it is limiting my riding, im gonna just strangle it frm now on!
« Last Edit: December 31, 1969, 04:00:00 PM by ' »

Offline _X_

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« Reply #3 on: January 26, 2013, 05:38:40 PM »
right, once you get a feel for where it falls flat you will be shifting before it reaches that point. good luck ash.
« Last Edit: December 31, 1969, 04:00:00 PM by ' »

Offline SachsGS

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« Reply #4 on: January 26, 2013, 08:18:27 PM »
Limit used to be 4000 feet per minute piston speed. Not sure what it is now with modern materials.
« Last Edit: December 31, 1969, 04:00:00 PM by ' »

Offline Stusmoke

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2 Stroke Rev Limits
« Reply #5 on: January 26, 2013, 08:48:47 PM »
Really you've just got to get a feel for the bike. My 01 CR125 is, by 125 two stroke standards, quite forgiving. I started out by taking it "slow" and listening to my motor and combining that noise with when it felt like it was pulling hardest. Now for me that zone was quite up there but your bike could be different. Anyway like everyone else says, you want to shift just before it falls off the pipe. I always say go slow to learn fast and its good here too.

I would suggest that you find a nice flat long patch of dirt and practise keeping it in the sweet spot when its wide open. Its harder than it sounds, even in a straight line on flat ground.

Good luck, don't stress. IT takes hours of practise for anyone.
« Last Edit: December 31, 1969, 04:00:00 PM by ' »

Offline msmola2002

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2 Stroke Rev Limits
« Reply #6 on: January 26, 2013, 10:10:33 PM »
I ran my RS125 GP bike (cr based engine) to 14k by the tach.
« Last Edit: December 31, 1969, 04:00:00 PM by ' »

Offline motoman356

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« Reply #7 on: January 26, 2013, 11:24:04 PM »
most modern bikes have rev limiters. i believe 125s are limited to about 12500 and 250s 10500? dont quote me on those figures but manufacturers generally put a rev limiter in just as peak horsepower starts to drop
« Last Edit: December 31, 1969, 04:00:00 PM by ' »

Offline 2T Institute

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2 Stroke Rev Limits
« Reply #8 on: January 26, 2013, 11:43:35 PM »
Ok so i was wondering exactly how far can you rev your 2 stroke, i know they dont have rev limiters as such, to what point can you keep the throttle on full before you need to change up a gear?

I find i probably change gear way to early cos im conscious of blowing the engine (if thts possible), just after its been in the powerband for a few seconds, i know this is not right as when you listen to pros riding two strokes they maintain that really high revving sound, and you cant even really tell when they have changed gear, its like a continious noise.

So at what point do you all change gear, ive heard of people saying a technically sound engine can rev up to 20,000 rpm. what are your thoughts?

36,000 rpm is no problems. all depends on the bore and stroke of the engine to get your rpm ceiling


https://www.youtube.com/watch?v=5aBCQGq5Al4
« Last Edit: December 31, 1969, 04:00:00 PM by ' »

Offline Stusmoke

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2 Stroke Rev Limits
« Reply #9 on: January 26, 2013, 11:57:11 PM »
Ok so i was wondering exactly how far can you rev your 2 stroke, i know they dont have rev limiters as such, to what point can you keep the throttle on full before you need to change up a gear?

I find i probably change gear way to early cos im conscious of blowing the engine (if thts possible), just after its been in the powerband for a few seconds, i know this is not right as when you listen to pros riding two strokes they maintain that really high revving sound, and you cant even really tell when they have changed gear, its like a continious noise.

So at what point do you all change gear, ive heard of people saying a technically sound engine can rev up to 20,000 rpm. what are your thoughts?

36,000 rpm is no problems. all depends on the bore and stroke of the engine to get your rpm ceiling


https://www.youtube.com/watch?v=5aBCQGq5Al4

Holy crap... That sounded like a big arse mosquito. thats a high revving engine alright...

And to ashpeat, alot of people shift when they're in mid air and hold a gear on the ground. If they have to shift on the ground they shift with no clutch while wide open. Hence the continuous noise.
« Last Edit: December 31, 1969, 04:00:00 PM by ' »

Offline TMKIWI

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2 Stroke Rev Limits
« Reply #10 on: January 27, 2013, 07:53:33 AM »
85's rev to 14k
125's 12k
250's 9k
500's 7k

MX bikes that is. Road racers will rev more.

Hold it open till just before it falls flat.
« Last Edit: December 31, 1969, 04:00:00 PM by ' »
If you don't fall off you are not going hard enough

Offline Stusmoke

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2 Stroke Rev Limits
« Reply #11 on: January 27, 2013, 08:00:36 AM »
85's rev to 14k
125's 12k
250's 9k
500's 7k

MX bikes that is. Road racers will rev more.

Hold it open till just before it falls flat.

Are you talking about redlines or when the power falls flat?
« Last Edit: December 31, 1969, 04:00:00 PM by ' »

Offline TMKIWI

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« Reply #12 on: January 27, 2013, 08:05:12 AM »
When the power drops off.
« Last Edit: December 31, 1969, 04:00:00 PM by ' »
If you don't fall off you are not going hard enough

Offline shanes

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2 Stroke Rev Limits
« Reply #13 on: January 27, 2013, 10:21:35 AM »
85's rev to 14k
125's 12k
250's 9k
500's 7k

MX bikes that is. Road racers will rev more.

Hold it open till just before it falls flat.

Sounds about right
My TZ 250 GP bike reved to about 13,000

The NSR 500 I tested stopped making power about 11,000
« Last Edit: December 31, 1969, 04:00:00 PM by ' »

Offline metal_miracle

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2 Stroke Rev Limits
« Reply #14 on: January 27, 2013, 03:44:36 PM »
Think that the tm 85 max out at 15000

and that the cr125 prototype dual was max 20000
« Last Edit: December 31, 1969, 04:00:00 PM by ' »