Freestyle Terrible vibration

SmittySX

SmittySX

Location
Cleveland, Ohio
I will try and explain this the best i can. This ski vibrates really hard right above idle then goes away for the most part but during higher RPMs you can still feel it vibrate more than normal.

-First i change out my lightened flywheel for an OEM, same thing.
-I disconnected the engine moving it forward of the couple and running it, it still has the vibration. Essentially, this rules out engine mounts, pump, and midshaft.
-Checked squish and its fine.
-Ive now taken the head off and inspected for anything un usual and it looks like new in there...

This is what ive narrowed it down to.. Im running a "new" SBT crank.. Im guessing its out of wack. Has anyone ever had this with them? Ive been lucky so far with what ive gotten.
Also i noticed when i popped the head off that the dome o rings were pinched in between the cylinder and the sleeve. What does this mean..?
 
Blue

Blue

Judging your cheapness
Location
St Cloud Florida
I have not seen this with any of the sbt cranks i have installed in our motors. But it is possible if its not aligned properly before its welded. Have you checked the compression to make sure one cylinder is not doing all the work? Do both piston tops look like they have an even burn pattern? And if you checked the squish that would rule of a bent or kinked rod.

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Fro Diesel

Fro Diesel

creative control
Location
Kzoo
What type of motor mounts?

How does slidding motor forward rule this out? Only swapping mounts will acheive this result.
 
SmittySX

SmittySX

Location
Cleveland, Ohio
Blue said:
I have not seen this with any of the sbt cranks i have installed in our motors. But it is possible if its not aligned properly before its welded. Have you checked the compression to make sure one cylinder is not doing all the work? Do both piston tops look like they have an even burn pattern? And if you checked the squish that would rule of a bent or kinked rod.

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Click to expand...
190 psi each


Fro Diesel said:
What type of motor mounts?

How does slidding motor forward rule this out? Only swapping mounts will acheive this result.
Click to expand...
Brand new OEM couch mounts. I guess your right in a way. The engine still vibrates the same attached or unattached as far as i could tell..

Working on other skis so i can ride today. Will tinker with it today or tomorrow.
 
Ducky

Ducky

Back in the game!
Location
Charlotte, NC
SmittySX said:
Correct. The pump is aligned perfectly.

I just noticed that my PFP chamber was touching the hull... Could be transitioning the vibration of the pipe to the hull..? Thatd be an easy fix.. lol.
Click to expand...

My PFP chamber was rubbing on the side of my hull, but I didnt experience any vibrations from that.
 
JRock637

JRock637

Location
Annapolis, MD
I have nearly the same problem. I get a loud vibration just over idle or on decel just before idle. Been chasing it all season, started when I pulled the motor over winter an put in new OEM mounts. Aligned perfect, with the tool, nothing's loose, and the ski ran all season last year never did this till I replaced mounts to new. Mines a 15 edge, checked the rails with the motor out not long ago they are tight, bolts even have locktite on them. Put motor back in still get the vibration.


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SmittySX

SmittySX

Location
Cleveland, Ohio
cookn said:
What hull. A guy in our group was fighting serious vibrations in a rickter and it turned out to be the engine plates that hold the motor mounts and bolt to the hull were slightly loose.
Click to expand...
RIP hull.


JRock637 said:
I have nearly the same problem. I get a loud vibration just over idle or on decel just before idle. Been chasing it all season, started when I pulled the motor over winter an put in new OEM mounts. Aligned perfect, with the tool, nothing's loose, and the ski ran all season last year never did this till I replaced mounts to new. Mines a 15 edge, checked the rails with the motor out not long ago they are tight, bolts even have locktite on them. Put motor back in still get the vibration.


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Click to expand...

Thats exactly where mine is. So did you ever change the engine mounts?
 
JRock637

JRock637

Location
Annapolis, MD
I changed from SBT ones to oem ( tore SBT's )that started the vibration problem ever since. Had the motor out twice an re-aligned twice. I'm thinking it's mid shaft or bent drive shaft. Possibly pump bearings?

I know one thing the vibration is so loud you hear an feel it rattle the fire wall loud as hell.


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Blue

Blue

Judging your cheapness
Location
St Cloud Florida
I had a similar loud noise in my freak once. It was due to the steering cable being routed under the motor. My problem went away when it was revved up mainly just at idle or lower rpms.

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