RX DI Violent Shaking

[daniel12]

I was out on the lake with my RX DI when after about an hour, it out of the blue stated shaking. I shut the motor off to avoid further damage and towed it back to shore. I am not getting any maintenance lights and the machine still starts fine but when it does start it shakes and sounds very bad. Where would I start diagnosing this problem?

Driveshaft and pump removed, problem persists.

Compression is 125 PSI in front and 129 in rear

 

[SabrToothSqrl]

Compression test. Verify engine mounts are good.

 

[mikidymac]

I would see if you have something stuck in the pump.

 

[daniel12]

Compression test. Verify engine mounts are good.

Compression is 125 PSI and 129 PSI. Tried shaking the engine by hand and it doesn't move.

I would see if you have something stuck in the pump.

Checked the impeller from the bottom and rear, it is clean. I believe the issue is engine related. I just started it up again for a second and now its making a noise that almost sounds like the piston is hitting something. I'm going to check the RAVE valves and make sure the piston isn't hitting those.

 

[daniel12]

Update: I removed the RAVE valves and noticed one of them has a bit of damage right at the lip. I’m not sure if this is what is causing the issue.

 

[Digdog]

I wonder if the counter balancer has somehow failed.

 

[daniel12]

I wonder if the counter balancer has somehow failed.

Is there a way to check this without ripping the whole engine apart?

 

[tobytd]

check piston / rings, look down rave slot

 

[daniel12]

check piston / rings, look down rave slot

I did that. They look okay, but i can only see a small portion.

 

[jhjesse]

Pull the pump and check for a rock in the impeller/bent driveshaft.

 

[daniel12]

Pull the pump and check for a rock in the impeller/bent driveshaft.

I have checked the impeller and pump, they both are clean. Here is a video to help better diagnose the problem.

 

[Digdog]

You're going to have to start somewhere, so remove the pump and driveshaft then see if it still makes the same noise/vibration.

 

[Digdog]

I have checked the impeller and pump, they both are clean. Here is a video to help better diagnose the problem.

Almost sounds like a piston had too much side clearance and the skirt hooked a port and broke off.

 

[mikidymac]

Yes, that sounds bad. Also someone has already had the head off because the gasket isn’t painted like it was from the factory.

 

[daniel12]

You're going to have to start somewhere, so remove the pump and driveshaft then see if it still makes the same noise/vibration.

Just finished removing the pump and driveshaft. Still the same thing.

Yes, that sounds bad. Also someone has already had the head off because the gasket isn’t painted like it was from the factory.

Yes, I bought these off my uncle who had a guy rebuild them 2 years ago. He didn't ride them for 2 years after the rebuild because he didn't have time for them anymore. I bought them and put ~10 hours on them and now this. Anyways, we know its not the drive system now!

 

[jhjesse]

Ugh...
I guess pull the head and check for excessive cylinder slap.
Counter balance....

 

[daniel12]

Ugh...
I guess pull the head and check for excessive cylinder slap.
Counter balance....

Any special way to test this stuff? Will I have to depressurize the fuel system first? I will tackle it tomorrow.

 

[jhjesse]

Nope. Just disconnect the battery and remove the hoses at the fuel rail by removing the Allen screw/keeper.

 

[Digdog]

Pull the engine, there are parts and pieces where they shouldn't be.

 

[daniel12]

Nope. Just disconnect the battery and remove the hoses at the fuel rail by removing the Allen screw/keeper.

In the process of pulling the head right now. How would I check to see if the counterbalance has failed?

 

[SabrToothSqrl]

I bought a XP someone rebuilt, and it shook horribly. Was the counter balance shaft.

 

[daniel12]

So, cracked the engine and found this... crank and counter balance gears both destroyed

 

[Digdog]

Ouch!! I have always been an advocate for synthetic oil in two strokes (any engine actually) costs a little more while it's operating but I believe it saves engines in the long run. Did you notice if there was any oil still in where the gears are? Or did it leak out?

 

[daniel12]

Ouch!! I have always been an advocate for synthetic oil in two strokes (any engine actually) costs a little more while it's operating but I believe it saves engines in the long run. Did you notice if there was any oil still in where the gears are? Or did it leak out?

There was oil coating the case walls. I know Bombardier only calls for 30-40mL of oil in there so I'm not actually 100% sure if there was enough or not. I would say not. I'm unsure if there was a leak

 

[Digdog]

Looks like the guy who rebuilt it forgot to add oil to the gear case since it has been 10hrs after the rebuild.