Surfriding What has been your best and worst experience with crankshafts in your motor builds

[masterblaster]

good post..there are always variables in any failure,but many of the failures we are starting to see are looking the same way. Brokin rods,Ive yet to see a locked up bearing that caused it,im sure it may have happen,but no where near as often as the random rod failures, I dont hear about many bearing issues recently,the rod usually goes long before the bearing wears out.Have seem some sloppy wrist pin bearings cause rods to break.With these big SS motors, cage-less bearings and checking them more often is the best maintenance you can do for your setup.

 

[BIGRED Z]

I just bought a BB motor last year that had a New SBT crank in it. Rode the ski all season with two trips to wave daze and countless hours of local riding. I fogged the motor and pulled the engine in october. Normally I would just reassemble the ski and hit the start button and she would have fired right up but I did a full inspection on the parts and turned the motor over by hand. I felt an odd (very small) bind or catch feeling. Because I was in the same boat the year before and lost a Crank with took out the top end as well I chose to break the motor all the way down and do a full inspection. What I found was the center crank bearings were rust coated and the center rear bearing (pto side) was binding badly. The point is I could have fired it normally and ran it with most likely a crank failure sometime during this season at a high repair cost. I would have most likely said at that time it was the SBT crank that failed and added my 2 cents to a bad review. The fact of the matter was I sucked in some salt walter (maybe more than a little ) and the motor doesn't like salt water then it sat for 5 months.

A little preventative maintenance goes a long way, it may take a little time but far less $$ if things are check out right.

just my opinion.

 

[masterblaster]

Strange,it had enough salt water still in it to rust the bearing that badly if you put it away for 5 months running,blownout and fogged also.

 

[rossthaboss11]

I have had a stock crankshaft bearing lock up on me. It was the rear bearing, and possibly the middle bearing I cant remember. This crank had many years of riding on it but it was pretty crazy how it happened. The ski sat on the beach for an hour or so with some water in the hull. Fired it up, idled for 10 seconds and rode off and 20 feet later it just died on me. The motor totally locked up due to the bearings. Probably had some water intrusion. With over 50 ft-lbs on the flywheel the thing didnt budge.

 

[Scraggly]

i had an oem crank come loose and destroy a top end and set of cases. it was weird though. rode all week in sc on hartwell. put the ski up and came home. day or 2 later me and will head to the lake. got in the water and clunk! it must have done it as it reved down from a blow out in sc. but no strange noise or anything.


edit: it did have A LOT of hours on it and i dont think it failed me in anyway i just pushed it a little longer then i should have.

 

[BIGRED Z]

Strange,it had enough salt water still in it to rust the bearing that badly if you put it away for 5 months running,blownout and fogged also.

Strange is exactly what I thought. Still had fogging oil in the cases when I cracked them.

 

[JetManiac]

I just bought a BB motor last year that had a New SBT crank in it. Rode the ski all season with two trips to wave daze and countless hours of local riding. I fogged the motor and pulled the engine in october. Normally I would just reassemble the ski and hit the start button and she would have fired right up but I did a full inspection on the parts and turned the motor over by hand. I felt an odd (very small) bind or catch feeling. Because I was in the same boat the year before and lost a Crank with took out the top end as well I chose to break the motor all the way down and do a full inspection. What I found was the center crank bearings were rust coated and the center rear bearing (pto side) was binding badly. The point is I could have fired it normally and ran it with most likely a crank failure sometime during this season at a high repair cost. I would have most likely said at that time it was the SBT crank that failed and added my 2 cents to a bad review. The fact of the matter was I sucked in some salt walter (maybe more than a little ) and the motor doesn't like salt water then it sat for 5 months.

A little preventative maintenance goes a long way, it may take a little time but far less $$ if things are check out right.

just my opinion.

This is the cause of many crank failures in my opinion. It is important to fully dry out a ski before storage.

 

[extreemthrottle]

i just tore down a kawasaki 1100 because it wasnt running correctly and i wanted to change crank seals. what i found still kind of baffles me. the labrynth seal was shot to hell and both bearings on either side were still good. the seal has approx 2mm of play in it both side to side and vertical. the crank is a wsm, and i would love to completely tear it down and see where the failure has happened. the rest of the crank still looks pretty good too.

being a yamaha tech for years, i can say ive seen many failures on oem yamaha cranks, mostly due to lack of oil, or pm. my favorites were motors that still ran with a rod that sawed the motor in half. sad to say but most customers thought it just needed a tune up.

 

[masterblaster]

lol tune up huh...serious tune up.. When you refer to lack of oil,do you mean not mixed at the right ratio,or none at all?

 

[masterblaster]

Strange is exactly what I thought. Still had fogging oil in the cases when I cracked them.

what brand did you use to fog the motor

 

[Matt_E]

This is the cause of many crank failures in my opinion. It is important to fully dry out a ski before storage.

If I don't tear the motor down for inspection during storage, then I at least remove the plugs, crank a few times, put oil in it, and leave the hood off.
Usually I tear it down, though. The high performance motors are too expensive to be cheap on preventive maintenance.

 

[BIGRED Z]

what brand did you use to fog the motor

Not sure of the exact brand? I picked up a few cans three or four years ago which the labels aren't the most legible anymore. The only the I remember about that cans was they had a black label w/ a yellow background behind red lettering. I' m pretty sure I grabbed them from my shop when another guy left them ?

 

[Jet Set Performance]

Any of you experienced bad thing with SBT crank ?

I'll never use an SBT crank again. Wish I would have taken a pic of the carnage on the Ultra 150 engine the SBT crank caused before I scrapped it.