Sbt cranks longevity?

superjetincairns

superjetincairns

Location
Cairns Australia
I've read quite a few horror posts regarding rebuilt sbt cranks but most of them are 3-4 years old now ( the posts). What's the current opinion of these? Im about to begin a full rebuild of my 701 engine. 82mm pistons, cleaned up ports, msd enhancer & Ada head with 35cc domes. Am i asking for trouble with an sbt crank or should i go with an inspected oem replacement. I want it fast but more importantly reliable.
 
Scraggly

Scraggly

Location
hhh
Oem is best but pricey. If I was going to buy another sbt crank i would only buy one from @JetManiac he has had an impeccable record with them. He must test personally and reject the bad ones.
 
Roseand

Roseand

The Weaponizer
Site Supporter
Location
Wisconsin
I'm running one in my 701 with a b pipe, ada head with 180 psi and rev limiter set to 7800. I'm at 4 gallons of oil gone, so around 50 hours or so of pounding it pretty hard and it obviously must be doing okay! Has had water ingestion once already. I purchased mine from Jetmaniac as well.
 
superjetincairns

superjetincairns

Location
Cairns Australia
I would imagine and hope they have their s$!t together by now or the company(sbt) would have gone broke if their cranks were continually failing. I'm looking at buying from another vendor on this forum so I'm hoping all the sbt cranks are coming from the same place and are of the same quality. I dont want to have to chase a warranty claim from Australia.
 
Vumad

Vumad

Super Hero, with a cape!
Location
St. Pete, FL
I have a 718 limited, 170 PSI, B-pipe, lightened flywheel, pro-X pistons, my ski frequently sees sustained 5000+ RPM and it's not uncommon for WOT (Recreational riding, some racing when the guys who do race are practicing, less since I hurt my back, but not just blip blip blip for a trick).

52 hours on my tach. I'd have to check my log but I believe that's 45-50 hours on my crank. Ski has had water ingestion a few times. Sunk it a few weeks ago. Using Yamaha lube 45:1. Peak RPM WOT is 7250.

The way i see it. OEM cranks are much better, but at 3-4 times the cost, I'd rather just take my engine apart every 2-3 years, clean it real good, maybe paint it, swap out the crank and pistons.
 
Vumad

Vumad

Super Hero, with a cape!
Location
St. Pete, FL
superjetincairns said:
I would imagine and hope they have their s$!t together by now or the company(sbt) would have gone broke if their cranks were continually failing. I'm looking at buying from another vendor on this forum so I'm hoping all the sbt cranks are coming from the same place and are of the same quality. I dont want to have to chase a warranty claim from Australia.
Click to expand...

Yes and no.

I don't believe there is a question about their cranks for stock applications. I am sure a large portion of their sales comes from stock couch rebuilds. My superjet was about 6000 RPM WOT stock, now it's 7200 RPM WOT stock. That significantly changes the situation involving crank wear and durability.

The question is not do their cranks hold up. The question is do they hold up to *your* application. I hope I get the results Jetmaniac has, but my motor will see much higher sustained RPM than his freestyle ported motors.

As far as I know, all SBT parts come from the Clearwater, FL center. Also, the warrenty only covers the crank. If it grenades your motor, you only get a crank.

Not saying to not go with SBT. I did and so far I have been satisfied. Just passing on the research I obtained during my purchase.

Also, I did speak to the guy at SBT, forgot his name, sorry, very bad with names. I questioned the crank bearing quality. If I understood him correctly, he said the bearings come from Japan, not china.
 
superjetincairns

superjetincairns

Location
Cairns Australia
If mine lasts 2-3 years of whipping I'll be pretty happy. Jetski engine rebuilds are a piece of cake compared to motorcycle engines that im used to working on. No gearboxes, clutches etc but i just dont want to be pouring my money down the drain every few months. My ski wont be raced but i do want to be able to hold it wot without having to swim home when I'm riding on glassy lakes now and then.
 
Scraggly

Scraggly

Location
hhh
I've owned one and I didnt buy it from a reputable seller just a sbt dealer shop. It lasted about 30 seconds. There customer service was great after that sbt's not the shop. And want to send me another one for replacement. But it still killed my new top end and Ada head domes.

After that I went with oem for the new top end. It's never fun paying for two engines before you even get to ride.
 
MikeyB

MikeyB

H2O-Addict®
Location
Michigan
Scraggly said:
I've owned one and I didnt buy it from a reputable seller just a sbt dealer shop. It lasted about 30 seconds. There customer service was great after that sbt's not the shop. And want to send me another one for replacement. But it still killed my new top end and Ada head domes.

After that I went with oem for the new top end. It's never fun paying for two engines before you even get to ride.
Click to expand...

What was the failure mode?


Sent from my iPhone using Tapatalk
 
Quinc

Quinc

Buy a Superjet
Location
California
753cc 61x/61x ported 190 psi, all the bolt ons. Only have about 10 hours so far but all is good. Lots of wot.

Edit: also purchased from JM.
 
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superjetincairns

superjetincairns

Location
Cairns Australia
The main reason i asked was because most of the threads i read about sbt cranks going bang.were from around 2010. May have been a bunch of bad bearings or an alcoholic apprentice working in the factory for a while. There doesn't seem to be many other options over here in Australia either and for your info an sbt crank with a core exchange is $695 plus postage both ways in Australia. I hope jet maniac can give some insight into why his cranks have such a good reputation.
 
BruceSki

BruceSki

Formerly Motoman25
Location
Long Island
I've put together a few with SBT cranks from Jetmaniac. One was a stock stroke 865, one a jetworks 771 and the one I'm currently running is a stock bore/stock port 701 with msd all the way up, b pipe, Ada head with 33cc domes. I wring it's neck everytime I ride and it seems to be holding up well. 1 season old in a few weeks.

I have started fogging my motor a lot more midseason if I know I won't ride for two weeks. I think that should help me with rust issues and bearing life.

Almost all my engine blow ups have been due to water ingestion then small end rod bearing failure due to to rust on the bearing.
 
smoofers

smoofers

Rockin' the SQUARE!!!!
Site Supporter
Location
Granbury, TX
I have an SBT crank (from JetManiac) in a 62t/61x running a limited setup and have probably about 70 gallons through the motor, no issues.

I also have a sport spec HX that has been raced 3 seasons plus been the "beginner ski" for anyone that comes to ride but can't get up on the SJ. It has ingested tons of water and been raced HARD. I tore the motor down after 2 seasons of racing and the crank was in excellent shape. I don't expect to have any issues with it.

While I don't doubt that SOME people have had issues with SBT cranks I would be willing to bet 90% of the haters either have never used SBT parts or wouldn't admit to their own fault with blowing up a motor. SBT is an easy scape goat, but I have had nothing but positive experiences with their products and service.
 
cookn

cookn

Kamikaze
Location
where you live
I also have an sbt from JetManiac that has three hard seasons on it with no issues. I also checked it myself before installing it, incase it was bumped during shipping and it was well within the oem specs. I will be buying another this winter for a big bore build
 
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