Reliability/Maintenance of freestyle Superjets

S

SMP

Location
Denton, TX
I am curious about how often a modded (pump gas) freestyle boat needs top-ends/cranks. What other maintenance issues can I expect from one of these (i.e. MSD's needing replacement every X months). Sorry if this has been covered, I tried searching it out to no avail.
 
stanton

stanton

High on jetskis.
Location
atascadero,ca
thats a very broad question. whats your definition of modded?
i would assume even the sickest flatwater rider would try to keep it once a season. ive heard of racers going 8-10hrs a topend.
 
D

danjrowan

does top ends mean little bits and bobs like bearings and seals?
i think that this depends on the engine
if you are running like a 1000cc in a freestyle boat at a mad compression its gonna need doing every few hours
if you got a great engine builder, they can build you a ski with tonnes of power but doesnt need to run super high comressions and stuff meaning that your engine will last much longer.
for example: my ski is a full freestyle motor and its only running at like 175psi.
the engine has been built to such a spec that it doesnt need to run any more as the power i have now is brillaint!
it was overhauled at the end of last year and i will be changing the little ends once a year from now on ( it was bone stock last year)
the point i make is that in my opinion, if you have a good engine you dont need to push it so hard that it will always need rebuilding
cheers
Dan
 
W

wydopen

Guest
i think my ski was built in 2001...it been getting ridden quite a bit..no complaints yet..but mine isnt a full flatwater freestyle boat
 
SuperJETT

SuperJETT

So long and thanks for all the fish
Location
none
2-3 seasons for a complete rebuild for me, but it does depend on your amount of riding and who did the porting. More aggressive porting will lessen ring life so you will need topend jobs more often.

In other words, "it depends".
 
S

SMP

Location
Denton, TX
Sorry for the vague question, it was late when I posted.

I should clarify, I'm wanting to run as much as a pump-gas boat will allow - ported, piped (wet, B spec), aftermarket head (pump gas domes as mentioned), MSD/Advent ignition or similar, case porting, maybe stroked?, maybe on bb sleeves? I love a hard-hitting boat, but don't want to buy race gas and I won't run avgas. I am also only going to be running on fresh water (flat).

I've had problems with a race motor in the past, but some of the issues I had may have been as much my fault. But I did 2 top ends in 2 seasons (one of them was a "4-corners" - so that one was my fault). My MSD went out and must have done some damage, as I also needed a new pulser coil - the tech at the bike shop said MSD recommends you keep an extra MSD in your tool box (BS?). Another nearly spoiled day at the lake was saved by Slymo when my starter solenoid failed and the replacement I got from Havasu C&W also failed (salvaged, another mistake). And, it seems like I've read on Group-K's site about crankshafts only lasting a season or 2 on modded boats (though I know opinions on the "matter-of-factness" of Klemm's recommendations vary).

Thanks in advance, I know this is a broad, somewhat subjective question - I just want to know what some of your experiences are. The amount of money my Superjet required for maintenance was too high for me but may have been easier to swallow if I was prepared for it (saving $$) - however that cost may also have been offset somewhat due to it being a tired old raceboat.
 
McDog

McDog

Other Administrator
Staff member
Location
South Florida
Sorry to bring back an old thread but:

185 psi
stock motor
b-pipe
msd enhancer

How reliable would this setup be?
 
Boris

Boris

The Good Old Days
Location
The surf-less coast
mcdog said:
Sorry to bring back an old thread but:

185 psi
stock motor
b-pipe
msd enhancer

How reliable would this setup be?
Click to expand...

Here's what I have,
165 psi with a stock milled head
mild porting on a stock 6m6
pro-tec pipe

all that was done in the early '90's by the original owner. The ski never got much abuse until I got my hands on it 1 1/2 years ago.
It still has 165 psi (checked yesterday) and is running great.

I think a properly set up motor can last years, as long as the owner doesn't try to eek the last ounce of power out of it or sends it to the bottom of the sea on a regular basis.
 
J

John_Ciocca

Location
Carlsbad, CA
I basically have a limited setup on a 94 Superjet, 175psi, b-pipe, advanced timing, lightend flywheel, port matched, carbon tech reeds, I run it hard maybe 60 hours a year, underwater most of the time....

Get this.....it's the original engine....never been rebuilt....175psi in each cylinder today.

JC
 
Kaveman

Kaveman

Born in USA(not Kenya)
Location
texas but soon tejas
There are WAAAAY too many variables to give an accurate estimate as to how long an engine will last. If you want to maximize ride time and minimize down time either have a backup boat or have enough cash saved to do the repairs. Crank rebuild and topend DIY typically under $1000. Again it depends on what you are doing with it, how aggressive you are with it, how wild the setup is and how often and how severely you ingest water. You said flatwater, you will ingest water eventually. In my case quite often.
 
McDog

McDog

Other Administrator
Staff member
Location
South Florida
With 185 psi on a stock engine. Is it the crankshaft that is the weakest link(ie first thing to probably break)?
 
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