how not to kill your 2 stroke

[LaLongueCarabine]

After 7 builds and 9 engines, I've come to a couple of conclusions.

1. Some of these engines are beasts and run flat out for years.

2. Some of these engines die after a few months.

3. Proper breaking in of the engine is not just a good idea, but necessary.

4. When an engine starts to die, nothing seems to help. The vibrations get worse and the top speed drops.

5. After all of this I'm still not sure we know what we're doing.

6. Running flat out down hill will get you amazing speeds but seems to damage these engines. I had two die under me while going downhill, there was a shudder and a slight pop. After that the top speed was 3-4 mph lower and the vibration at speed was terrible and I had to wear gloves and hold my hands replaxed.

Why? I know it has high RPM but no load it's falling down the slope. The bearing surfaces shouldn't be hotter that normal. The throttle is lower so maybe there isn't enough oil?

 

[Theon]

Sounds about it.
if your motors doing high revs and your throttle is off then it cant pull the necessary oil.

 

[xseler]

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7. Just when you thought you've got it all figured out, something will happen that'll snatch you back to reality.

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[Will122391]

I broke my engine in real gently for 200 miles and have run it near WOT ever since with no problems. I think going downhill while revving high is a bad idea because there is no load. The engine is being dragged along for the ride.

 

[The_Aleman]

The 2-strokes oil themselves under load, this is why it's long been said in the forums to pull the clutch in when going downhill.

If you do that and don't allow the engine to rev much over 6K RPM ever, it will last a lot longer.

 

[2door]

The 2-strokes oil themselves under load, this is why it's long been said in the forums to pull the clutch in when going downhill.

If you do that and don't allow the engine to rev much over 6K RPM ever, it will last a lot longer.

Ditto:

Downhill? Pull in the clutch and don't try to see how fast you can go. Over reving the engine, any engine, is asking for trouble.

Tom

 

[Theon]

6000 Rpm is probably a good Idea, but my motors come to life around there,
Guess it depends, on what you want your bike for.

 

[Goat Herder]

My Morini ''Not a Happy time motor lol''
I stay buried into the throttle uphill downhill and sideways... Till I get to speed then I mix it up a little. I am tuned for what I am doing too which helps oiling. Carby is over sized and tuned on the rich side. Like a little dragster engine @ 12k rpm..

What these folks are saying is very true pull your clutch in and do not over rev it! it will last a lot longer! the little China HT engines are not built precision. They are still a ton of fun and can be reliable if taken care of.

Mine on the other hand hitting the big 20K now OK lol about 15000. who's counting

 

[LaLongueCarabine]

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7. Just when you thought you've got it all figured out, something will happen that'll snatch you back to reality.
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Amen to that! Thanks for the responses, the last two engines we are not running flat out down hill and they are still running great after 6 months.