FREESTYLE(Run time on these setups)STROKERS

[HBCwatercraft]

Figured id make a thread on expected runtime on these
convigurations. These will be put in a all out class, for example fully ported, epox cases with billit plate or full billit cases, dual 48 or 49 carbs, 195psi and up/flattops, we will throw msd tl in as well.

8mil
10mil
12mil
16mil

I was told by a couple builders that a 8mil setup with 85 bore witch i have has a runtime of aprox 32hrs before a top end break down for inspection possible freshup with rings and pistons and 62hrs for a lower end rebuild or inspection.

With the 10mm i was told full comp motor witch will see a breakdown every 25-30 gal of fuel.

Now is there any truth to this, i know diff builders and setups will prolong the life but lets say it was build right and followed the specs shown above. I picked my setup not with price but on runtime and if it could meet my needs. Backflips, and still be able to perform basic tricks with control...such as hood trics ect. Id like people to chime in that have had these motors and a word from engine builders on this subject. Pro's and cons on big stroke with 85 bore vs the xxl big bore 91mm. Is it better to build a 8/10/12 with a 85 flattop or go all out to 91 bore
with the same strokes. We will asume cost does not matter
on this subject. I see run time getting lower as the stroke increases for sure due to rod angle...but are the hrs or gals in the right ball park for teardowns?

 

[Waternut]

I was told by a couple builders that a 8mil setup with 85 bore witch i have has a runtime of aprox 32hrs before a top end break down for inspection possible freshup with rings and pistons and 62hrs for a lower end rebuild or inspection.

With the 10mm i was told full comp motor witch will see a breakdown every 25-30 gal of fuel.

If that's accurate predictions, that sucks! You'd barely get it broken in before you have to rip it apart again. I think the major engine upgrade just got wiped off of my dream list. WOW!! That wouldn't even last half a season. mfg:

 

[Boris]

Can't be all that bad.

I was told that if I wanted a stroker (6mm) I should pull the motor down once a year for inspection purposes only.

Stock stroke big bores run for years and years though.

 

[HBCwatercraft]

That is why im starting this at 8mm. Starting from a 8 and up
seems to be were issuses and limits start to get pushed. Sounds about right if u were told to tear down for inspect once a yr then 32-40 hours sounds about right for a 8mm.

 

[crammit442]

I was told by a couple builders that a 8mil setup with 85 bore witch i have has a runtime of aprox 32hrs before a top end break down for inspection possible freshup with rings and pistons and 62hrs for a lower end rebuild or inspection.

With the 10mm i was told full comp motor witch will see a breakdown every 25-30 gal of fuel.

I think someone wants to sell you parts and service....... That might be accurate if you were building a full race motor that was used as a race motor. A freestyle motor will never see the R's that a race motor sees and should have much longer service intervals. I agree with the yearly piston/bore inspection/replacement, but unless you have corrosion issues, a crank should easily go two seasons and probably three safely. A season is roughly 5 drums of fuel for me. A drum is 11 full 5 gallon tanks of fuel, so 55 full tanks in a season. 75ish hours of run time. At that point the pistons may be a bit worn, but you should be ok with a hone and a fresh set of pistons(assuming good oil). You may even be able to go two season depending on how aggressively the motor is ported. On another note, how does anyone even come up with a recommendation of hours like 32 or 62???? What makes 32 or 62 special instead of 30 and 60????:thinking:

 

[Matt_E]

Sounds more specific than 30 / 60! :bigok:

 

[Boris]

Screw that, I ride too much to ever get a stroker than.
6 top ends every year ?
No thank you.

 

[puppy]

How about a 61x big bore and ported by jetworks or lpw

 

[McDog]

Wow. My future monster motor is looking less likely to be a stroker. I live on my ski during the summer.

 

[Waternut]

What makes 32 or 62 special instead of 30 and 60????:thinking:

Probably computer simulated those numbers. The 32 hour inspection would be the point at which a crack or problem could be detected if a rogue flaw existed (small tooling mark, scratch, metallic impurity, etc. since nothing is perfect). The 62 hour mark would be the point at which the simulation reached the max safe limit or the part actually failed. You see that stuff in aviation all the time. They don't quote you 7500 or 8000 hours...you get 7823 hours on your inspection.

 

[butti]

Probably computer simulated those numbers. The 32 hour inspection would be the point at which a crack or problem could be detected if a rogue flaw existed (small tooling mark, scratch, metallic impurity, etc. since nothing is perfect). The 62 hour mark would be the point at which the simulation reached the max safe limit or the part actually failed. You see that stuff in aviation all the time. They don't quote you 7500 or 8000 hours...you get 7823 hours on your inspection.

your right,it was prolly a computer simulation.

 

[HBCwatercraft]

No, this is from testing they have come up with those numbers.
No computer came up with those figures. I know the more stroke u have and hp u get...the higher the compression, the more unreliable the setup gets as well as runtime. Procircuit use to do my motors full out and they came up with a rebuild time aswell as my time on race sleds 440 class.When i use to race two stroke dirtbikes before 4's came out the rings were replaced every 25 hrs. A 12mm stroker isnt going to last as long as a stock stroke nor a 8mm. Unless jetski motors are any diff from anything eles. If i knew for a fact that a 10mm stroke would last just as long as a 8 and was just as reliable then i wish i went with a 91bore with a 10mil stroke cuz the $ between the 2 isnt that much diff. Id hope the 8mm was more trust worthy. Any board members own a 10 and up stroker that can speak on its behalf?

 

[Aircraftsalz]

Call Xscream. When I picked my ski up I was talking to Radney about how many hrs/gallons to run my stroker. He was telling me that the pumpkin (pat's ski) ran 1yr 3 months before it was pulled apart. He said that ski runs every weekend on race gas & has had a lot of hrs/gallons through it. 1000cc motor that I'm sure isn't babied!

 

[yamanube]

Depends on who puts it together, if you assemble it.....

 

[Matt_E]

How about a 61x big bore and ported by jetworks or lpw

Art told me 3 years before inspecting it to see if it needs pistons/rings.

Wow. My future monster motor is looking less likely to be a stroker. I live on my ski during the summer.

Why? Because someone on the Internet said that he's heard someone say they don't last long? :biggrin:

 

[Aircraftsalz]

Depends on who puts it together, if you assemble it.....

Thats everything IMO. Plus its the complete package that makes these motors rip.

 

[HBCwatercraft]

hmmm 1yr 3 months impressive.

 

[Scorn800]

Probably computer simulated those numbers. The 32 hour inspection would be the point at which a crack or problem could be detected if a rogue flaw existed (small tooling mark, scratch, metallic impurity, etc. since nothing is perfect). The 62 hour mark would be the point at which the simulation reached the max safe limit or the part actually failed. You see that stuff in aviation all the time. They don't quote you 7500 or 8000 hours...you get 7823 hours on your inspection.

Aviation is alot more precise than jetski's:spank:

I can't see a freestyle motor needing to be pulled down more than once a year for inspection.

 

[Tanman]

That is extremely impracticle if you ask me. I see myself building a sick ski every year. and I not only can't afford another one but really don't have the time. So ya I want that power but I don't have the time for 32 hours of riding and then yank the motor. Thats like 4-6 weeks of riding for me in the summer.

 

[grezzmky]

Art told me 3 years before inspecting it to see if it needs pistons/rings.



Why? Because someone on the Internet said that he's heard someone say they don't last long? :biggrin:

you went stock stroke, didnt you Matt? how is that thing? My setup is BB and 46 Blackjacks like yours but Arts 4mm crank... Im really excited!