Topic: 2 stroke engine problem

[2wheels]

I have a 500 cc 2 cylinder, liquid cooled, 2 stroke.

It runs fine at idle and midrange, has the expected power there as well.
Anything past half throttle there is just nothing. 
The motor still sounds fine power does not change.  No coughing and sputtering.  Just no increase in power.

Any ideas?
Carbs have been cleaned several times, but I'm not saying I did it right.
Ignition is CDI

[CycleRanger]

I have a 500 cc 2 cylinder, liquid cooled, 2 stroke.

Oh oh I'll guess it's a....Rotax?   A... Suzuki?  A... Bimota???

[2wheels]

Rotax
In a a 20 year old Ski Doo

[CycleRanger]

Hah! First guess!

Are you sure the throttle cable is adjusted correctly? Sounds like the carbs might not be opening all the way.

[2wheels]

It sure feels like they are not opening up.  But I checked and they are.
I was thinking the main jets are sized wrong (they may be) but I think with the throttle wide open the mixture would be so far off the engine would run really bad. 
But that is not happening.

I should add this is a franken-machine / barn find.  So anything is possible.
Probably not a good choice for my first 2 stroke repair experience.
But hey,  it was free and we are having fun.

[CycleRanger]

It sure feels like they are not opening up.  But I checked and they are.
I was thinking the main jets are sized wrong (they may be) but I think with the throttle wide open the mixture would be so far off the engine would run really bad. 
But that is not happening.

I should add this is a franken-machine / barn find.  So anything is possible.
Probably not a good choice for my first 2 stroke repair experience.
But hey,  it was free and we are having fun.

It doesn't have some kind of governor on it does it? 

Free? That's the best price!

[2wheels]

89 ski doo Clutch

here is a video of the clutch operation,  we were thinking this may have been the problem but now I am not sure.
Anyway with the back end of the machine tied in the air we could open it right up.
It does say something that it will open up when there is no load on it.

There is no speedometer so I'm not sure what a governor would look like.

[CycleRanger]

89 ski doo Clutch
There is no speedometer so I'm not sure what a governor would look like.

Well, I know nothing about these engines but there may be an electronic module that limits RPM.
Just guessing.
I'd go googling for a shop manual. If it's that old there's bound to be one online somewhere.

[strynboen]

mine yamaha dt..have same problem,, it vas the ignision coil extern..took one from a china dirt bike..and it runs super fine

[2wheels]

I never thought of a governor before you mentioned it. 
It is a good possibility so I wil check into that.

[2wheels]

strynboen
I was hoping it is not ignition.  All these parts are so expensive.
But as you discovered it can be.
I may need some spare parts I can swap to find this problem.

[mrrch]

If it was actually stored in a barn check the exhaust for blockage (mouse nest/ happens alot with snowmobiles )

[faux fiddy]

If it was actually stored in a barn check the exhaust for blockage (mouse nest/ happens alot with snowmobiles )

+1

Mud daubers  and wrens can work in the holes , too.

[2wheels]

Thanks
The expansion chamber is off right now.  I will put some large nuts and bolts in and rattle them around.

[Retro Rocket]

Rotax
In a a 20 year old Ski Doo

Put it in a bike......