2 stroke technique

Stinky

Stinky

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We had a 2 stroke blow this week.  It clatters like crazy....rod bearing?

Anyways, some of the folk around camp said that the driver blew it up because he didnt periodically let.off the gas and that you need to do this on a 2-stroke.  

You ever heard of such a thing?

 
I have heard it.  Not sure if it's 100% true.  Something about high RPM cooling/lube when on decel.

I used to ride my old 250R from Gecko to GBS pinned damn near the whole way.

 
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Two-stroke motors are not meant to be revved at constant high RPMs. 
 

On the gas off the gas on the gas off the gas… and constantly shifting gears to hit those peak RPMs.

 
Stinky said:
We had a 2 stroke blow this week.  It clatters like crazy....rod bearing?

Anyways, some of the folk around camp said that the driver blew it up because he didnt periodically let.off the gas and that you need to do this on a 2-stroke.  

You ever heard of such a thing?
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I ride a modern one (fuel injection) but I still find myself hitting the kill switch a couple seconds every once in a while while holding wide open. Old habits are hard to break and I don't want to seize up at speed. 

 
impropper oil ratios or wrong jetting is what causes failures typically not high rpm specifically. thats just when you happen to find out theres an issue since the oil ratio and jetting are more critical at high rpms.

look at other 2 stroke engines like weed eaters, outboard boat engines.. which i have a 2 stroke outboard on my eliminator daytona and i run that thing pinned for miles at a time when i head up river to topock.

 
What is the engine size?    

Most of the time it comes down to correct jetting   (Always just a hair “fat” for the dunes.)

Look for air leaks even crank seals can be the problem 

 
Indian Joe said:
What is the engine size?    

Most of the time it comes down to correct jetting   (Always just a hair “fat” for the dunes.)

Look for air leaks even crank seals can be the problem 
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THIS 

Remembering to jet fat for sea level if you're normally jetted for higher elevations can be overlooked too. Ask me how I know

 
He was duning? Almost have to let off in the dunes. Not like flat open desert where you can hold it steady for miles and miles. 

There is definitely a technique to riding cool in glamis. Hard to explain but its a much smoother approach. You can carve sharp lines but it adds resistance and works the motor harder. When my bike starts getting hot i will take wider turns. Maintain momentum. Its not as fun riding that way. 

 
Kat-A-Tonic said:
This also works at 3:00 am in wash 6...
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That's what I was taught as a kid....LOL

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Stinky said:
We had a 2 stroke blow this week.  It clatters like crazy....rod bearing?

Anyways, some of the folk around camp said that the driver blew it up because he didnt periodically let.off the gas and that you need to do this on a 2-stroke.  

You ever heard of such a thing?
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Fake news. I’d hit 110mph 6 gear pinned for miles at a time racing the old 250r.

The old wives tale was don't hold it wide open then chop the throttle off (no fuel/oil suddenly at high rpm).

 
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What bike is it? If it’s an oil injected bike, like a blaster, you need to ditch the oil injection and premix the gas yourself. 

 
I recall reading my first Banshee manual (first ever bike, learned to ride on it) and it mentioned not staying in the same throttle position for extended periods of time.

But I think that was for initial break-in period.

 
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I was taught, a long long time ago that you use the clutch when slowing down and blip the throttle. The theory is since the motor only has lubrication when fuel is moving through the motor when you close off the throttle but let the wheel spin the engine it’s bad for the crank bearings. If you constantly engine brake when riding downhill it could take a toll over time. 
More likely it’s a little lean on the main jet or mix is off. 

 
We raced CR125's in our shifter karts at Daytona for Kart Weeks - pinned for at least 3/4 of the time.  Probably ran it too lean for the weather like Pennywise said - main or fuel.  When "the air is good", it can catch you off guard if you're too lean.  Conversely increased elevation or increased water vapor/humidity can cause it to be too "fat".  Most people run two strokes safe to cover a variety of weather conditions unless you know what you're doing.

 
Sausage450r said:
Fake news. I’d hit 110mph 6 gear pinned for miles at a time racing the old 250r.

The old wives tale was don't hold it wide open then chop the throttle off (no fuel/oil suddenly at high rpm).
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Holy crap, that R must have been one hell of a build!

 
Durning my stretched out Toomey built days I would reach down and flip the choke on for the ride down the hill and clear out at bottom.  

 
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