Engine Life

prettyricky218

prettyricky218

Location
Minnesota
I'm wondering what kind of engine life to expect with these jetskis. From my understanding a stock 701 could last quite a long time, however as soon as you get into a big bore motor we're talking about a tear down to inspect it at 30 hours and overhaul at like 60 hours? Does this sound right? That seems like a pretty short period of time and I was looking at the XScream website where they have top end kits for sale which range from like 1-4 thousand dollars depending on how big of an engine you have.
I've been saving up and am about to pull the trigger on a sweet ski, but I need to know what I'm getting myself into as far as cost to maintain it, and just the knowledge to actually keep it maintained.
To me the more power the better, but does it really have to come at such a cost of high maintenance?

Is there a powerful motor set up that requires far less maintenance than I'm thinking?
Perhaps something that isn't stroked and running high compression heads?
Any info on what to expect and perhaps a set up that will give me more than one season of riding on an engine would be appreciated. I'm trying to learn all I can about these things.
 
Freakrider

Freakrider

X247
Location
Tampa Bay area
I've been told by an XS rider that they have gotten 200 plus hours out of a XS1200RR motor. If you run high performance, use only a high quality full synthetic oil. Currently at approximately 130 hours on a XS900R using R50 oil.
 
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S

SanoWK

Location
60014
Original bore on my 06 62t/61x superjet. Kept stock till 08 and installed bpipe, head, msd and still has perfect compression! Premium @ 40:1 klotz I'm thoroughly impressed
 
V

Vortex

Location
Southeast
I ran the poop out of a stock 701 from 2003 until 2015 until it ate a reed and it still had 145 compression. This was weekly closed course racing practice and occasional freeriding.

Higher power engines I would expect to have apart once or twice a year. At that time i would at least inspect and likely replace the reeds, that is a main moving part that can tear up your engine (not so much with composite reeds) and needs to be in good shape. Some people hone and replace pistons at that interval to keep it fresh. Cast pistons can last a long time until they crumble, forged will eat up the cylinders before they crumble...so for a h.o. motor on cast pistons I would have an hour meter on it and replace pistons at no more than 100 hours. Turning 7k+ rpm will also wear the crank out faster, so I'd estimate a replacement about every other season.

I'd run race fuel and 32:1 high quality oil like klotz or castor oil. That's what I'm going to do with my ported 701 at over 200psi that is run wide open. High quality fogging oil after every ride

And always change plugs or fuel mix if it's not hitting clean off idle.

I've ridden another ported 701 that was a very strong surf motor that had been together about 5 years, but it was very well tuned and cared for so it's a very case by case thing.
 
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OCD Solutions

OCD Solutions

Original, Clean and Dependable Solutions
Location
Rentz, GA
The X-Scream motors are using a stock OEM crank which is now handling over 900cc's for multiple seasons just fine. That being said, a well cared for 701 or 760 based engine, even if piped, ported and rode hard is still going to be beyond the 500hr range with minimal maintenance in between. Use good oil, don't ever overheat it and keep water out of the engine and you are golden.

I ran a piped and ported 61X 701 for several years before it required a rebuild. I lived on a lake for that period and rode from the day the ice came off the lake to the day it froze over again and the only thing I ever replaced was the battery and the Bendix. The only reason I rebuilt it in the end was because it ingested a stock reed petal and I tore it down to find it. It was still running great but I figured it deserved a rebuild after all it's years of service.

You can always buy more power but you can also build cheap power if you know what you are doing. I currently have an SS865 in my ski and a ported 760 in my wife's and am currently building a second 760 to drop in my ski this season. I can build a solid 760 for 1/5th the cost of my X-Scream motor and have just as much fun. It's not that much less power either. Granted i'm older now and not chasing the ragged edge anymore so I can make cheaper decisions. ;)
 
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prettyricky218

prettyricky218

Location
Minnesota
Freakrider said:
I've been told by an XS rider that they have gotten 200 plus hours out of a XS1200RR motor. If you run high performance, use only a high quality full synthetic oil. Currently at approximately 130 hours on a XS900R using R50 oil.
Click to expand...

Is that because that particular motor is stock stroke? Do I understand it correctly that you can get a bigger motor, as long as it's not stroked out and get over a hundred hours likely?
 
SUPERJET-113

SUPERJET-113

GASKETS FOR CHAMP BRAP!
Site Supporter
Location
Lake Havasu City, AZ USA
When i first moved here to Havasu 13+ years ago I worked for a ski/boat rental place for 6 months and they still had 2 stroke Yam 701 61X or 62T based sit downs with hour meters and they could 700-800+ hours on one before a rebuild was needed, and thats a rental with morons, spring breakers, etc. holding it WFO for miles at a time on a 3 seater Waverunner. So in a stand-up, stock can last a REAL long time.. You gotta pay if your gonna play!
 
V

Vortex

Location
Southeast
prettyricky218 said:
Is that because that particular motor is stock stroke? Do I understand it correctly that you can get a bigger motor, as long as it's not stroked out and get over a hundred hours likely?
Click to expand...

It's generally thought that larger pistons absorb more heat during the combustion process so 89mm plus is a bit more on the ragged edge so to say.

Longer stroke increases the rod angle so things have to be set up very carefully to handle that.

That's why the 771 was/is a popular choice
 
tntsuperjet

tntsuperjet

Tntperformance-engineering.com
Location
Georgetown ca
My square
Nose had a 6mm stroker 785cc total loss motor with 210psi comp in a race boat.
Motor was installed in 93 and ran till 2010.
Never rebuilt never inspected.
Gas oil run the crap out of it.
But in 2010 it was a total loss of everything but the cases.
32to1 oil.
80/20 pump race gas mix.

Boat ran 61mph in square nose no pump stuffer, long race plate.

But I built 223 of that same motor back in the day and customers blew them up within 5 hours.
The average life span was about 130hrs.
But the endurance race guys got over 200hrs and they held them wide open for miles.
So being a new rider I would say expect short life span from your first big motor.
Just because you will most likely over rev it hard trying new things and unload the motor at heavy throttle and the shock loads kill them faster then anything.

There was a comment made about cast Pistons crumble and forge Pistons eat up bores.
Cast Pistons if left in past there service limit will fail carastrophic.
I have taken head off and found a rod with a pin and no part of piston bigger then a dime. And poored the piston out the exhaust pipe.
But if you have the proper piston clearance and nickel content forged piston to your Cyl growth pattern and proper cooling your piston to Cyl clearance can be setup at .004-.0045 and they won't eat up bores.
Sloppy forged Pistons eat bores. Most setup forged Pistons .0055 to .0065. That will scuff bores much faster then .004 clearance motor.

Example. Cr250 race motors back in 2000 one set up with flat top wiseco 702ps piston at .002 clearance had 80hrs and no scuffing or intake wear.
Same motor setup at .0035 would have heavy intake port wear in 4hrs and need to be replaced

When you have open loop cooling system engine clearances have to be loosened up do to inconsistent cooling water temps and pressures.
That being said you have piston growth issue that few solve so they just take easy way out with
.0055-.0065 clearance. And that eats bores.
 
V

Vortex

Location
Southeast
tntsuperjet said:
My square
Nose had a 6mm stroker 785cc total loss motor with 210psi comp in a race boat.
Motor was installed in 93 and ran till 2010.
Never rebuilt never inspected.
Gas oil run the crap out of it.
But in 2010 it was a total loss of everything but the cases.
32to1 oil.
80/20 pump race gas mix.

Boat ran 61mph in square nose no pump stuffer, long race plate.

But I built 223 of that same motor back in the day and customers blew them up within 5 hours.
The average life span was about 130hrs.
But the endurance race guys got over 200hrs and they held them wide open for miles.
So being a new rider I would say expect short life span from your first big motor.
Just because you will most likely over rev it hard trying new things and unload the motor at heavy throttle and the shock loads kill them faster then anything.

There was a comment made about cast Pistons crumble and forge Pistons eat up bores.
Cast Pistons if left in past there service limit will fail carastrophic.
I have taken head off and found a rod with a pin and no part of piston bigger then a dime. And poored the piston out the exhaust pipe.
But if you have the proper piston clearance and nickel content forged piston to your Cyl growth pattern and proper cooling your piston to Cyl clearance can be setup at .004-.0045 and they won't eat up bores.
Sloppy forged Pistons eat bores. Most setup forged Pistons .0055 to .0065. That will scuff bores much faster then .004 clearance motor.

Example. Cr250 race motors back in 2000 one set up with flat top wiseco 702ps piston at .002 clearance had 80hrs and no scuffing or intake wear.
Same motor setup at .0035 would have heavy intake port wear in 4hrs and need to be replaced

When you have open loop cooling system engine clearances have to be loosened up do to inconsistent cooling water temps and pressures.
That being said you have piston growth issue that few solve so they just take easy way out with
.0055-.0065 clearance. And that eats bores.
Click to expand...

I want that 6mm motor!!!

I had started a kawi 1100 sj but I'm having second thoughts and thinking about selling that in favor of a high power twin.
 
jo5hi3

jo5hi3

Location
Charlotte NC
I had 2 seasons on my dasa 1000, which was probably close to 500 gallons of fuel if not more. I pulled it down once and replaced the top end bearings just to be safe. But it really comes down to how well you treat them, how much water they ingest, etc. But on anything with an aftermarket cylinder I would consider a tear down and inspection at the end of each season at a bare minimum.
 
tntsuperjet

tntsuperjet

Tntperformance-engineering.com
Location
Georgetown ca
Vortex said:
I want that 6mm motor!!!

I had started a kawi 1100 sj but I'm having second thoughts and thinking about selling that in favor of a high power twin.
Click to expand...
I haves 6mm 860 dasa 7 port complete. TNT ported
Haven't even finished it yet.
Fresh bore,new piston
Boysen reeds with dasa 48mm carbs
So head,Cyl, cases, crank complete intake.
All one needs to make run is coupler, starter and electronics
5,100.

Crank has about 12hrs on it
 
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