Super Jet Stroker Cranks

[masterblaster]

My 5mil crank has had four seasons on it at 195 compression and total loss and one season around 220 without ever feeling rough or loose on a yearly inspection running 86mm pistons. I know I'm past due on a rebuild but that still says something about longevity. I ride 100% freestyle/rec flatwater.

now thats some good luck,I have heard of some small bore strokers running this long before in the past,but not the norm..

Surf motors for big swell dont need to be super nasty power,just linear torque,surf motor for small surf and rec river riding boat wakes is another story..Lawler and tc owned everyone at last yrs small surf wavedaze on 1000 cc stroker motors
Dont think anyone really cares about 61x or 62t anymore,other than maybe the new superbore 62t. It was interesting that all xscreams and jm blue bigbores were built on the 61x platforms though.no one needed the extra rpms up top perhaps?personally never really was impressed by any of them for the $.The spec blasters are pretty nice power with the exception of all that needs to be off is a hair of anything and they feel reg smeg.Small stroker for life for me.........nothing need be perfect and they still rip,getem perfect and hold the ffff on...

 

[TheBuzzard]

Surf motors for big swell dont need to be super nasty power,just linear torque,surf motor for small surf and rec river riding boat wakes is another story..Lawler and tc owned everyone at last yrs small surf wavedaze on 1000 cc stroker motors

i dont know about TC, but lawlors did not have big motors until they just got 8mm 950s. brandon had an XS865SS in that foot rocket and randy had that XS900SS that never ran right due to an air leak in the epoxy work. they had 701s before that and still kicked ass.

 

[masterblaster]

lawlor was riding a 1000cc tc ski at wavedaze they trucked into Va. but yes to your point,in big cali surf a smaller torquey motor is fine

 

[TheBuzzard]

they both have dasa 8mil 950s in their boats. you could be right if he was riding something else.

 

[KTM434]

Surf motors for big swell dont need to be super nasty power,just linear torque,surf motor for small surf and rec river riding boat wakes is another story..Lawler and tc owned everyone at last yrs small surf wavedaze on 1000 cc stroker motors
Dont think anyone really cares about 61x or 62t anymore,other than maybe the new superbore 62t

So nobody cares about 61x and 62t based cylinders anymore? Taylor Curtis owned everyone at Wavedaze with his 1100... You don't think it was his riding skill? If he didn't have an 1100 would he be a squid in East coast surf? I know plenty of good surf riders that can shred with a 701. I understand your thoughts on power needs for east or west surf being different but I wouldn't say it's a fact.

 

[masterblaster]

dunno think lawlor was right there with him,sure they could ride a 701,but ive seen the results from both and you can DEFF see the fun factor and sick trick kick in with the bigger motors and the pros in small surf,and the rest of us as well....seems most everyone we know has a a/m motor of some type in surf these days,so not much interest in x or t much...

 

[kevbo]

OEM cylinders are like OEM hulls anymore.

 

[KTM434]

I guess it depends how you look at it. I think most of the best true surf riders are still on OEM hulls. Superjets and FX1s. Now if you are talking about bigges trick competitions at a Freeride event, that's a different type of riding and yes they usually run AM hulls and billet cylinders. As Masterblaster stated the surf conditions are much different from east to west. West coast can get away with linear power like a SS billet 850/865/900... Those engines will pull but they don't hit very hard off the bottom. East coast surf is usually much smaller and doesn't break in clean sets so you may need the quicker rev response to get where the waves are breaking and it's a much more agressive and sporadic type of riding to rip that type of surf. you won't be able to ride with the same type of speed on a wave face like in the west coast or you wil just ride out of the break. East coast surf just doesn't have the same powerful swells as west coast unless its hurricane season. Again this is all theory since different people prefer different setups but my big bore 771 hits harder and feels more impressive than almost any SS billet engine I've ridden. Strokers are a TOTALLY different story.

 

[masterblaster]

OEM cylinders are like OEM hulls anymore.

pretty much so these days.

ktm...you nailed it...billet and SS shouldnt even be in the same sentence imho or even a/m cylinder and SS for that matter,Stroker cranks are too affordable these days. what kinda ign,comp,fuel your 771 run? you need to just throw one of those small stroker able motors you got sittin over there in your ski...alot of bang for the buck in a freeride/rec ski right now,its crazy how cheap one can be bought for complete,wish more were around.

 

[KTM434]

85mm 771 pump gas 190psi, dual SBN44s on Riva mani with VF2s, B pipe bored to 50.5mm and NYNA chamber, MSD enhancer, JSS coil, stock heavy flywheel, stock 144 pump cuz I like it loose, hooker 10/16, stock reduction nozzle since I broke my 85mm nozzle and I'd rather have a part that won't break rather than an ounce of performance (in shallow sloppy surf) and I think I have a stubby pump cone in there to help unload the pump.
my big bore is also a 61x based cylinder. You say that people don't need the extra RPMs that run a 61x? My engine hits real hard off the bottom and will also get close to top speed within a few seconds which is faster than I'm really interested in going 99% of the time. I just do it on my way back from riding the inlet sometimes cuz it's fun after a good surf riding sesh. Even running 62t cylinder with the same setup, your compression and timing advance on pump gas isn't safe to hold WFO for sustained time anyway. If you talk to Art Gomez he thinks 61x cylinders have superior port layouts than most billet cylinders and doesn't believe power valves are necessary if the engine is setup properly. He's a very knowledgable engine builder but I'm sure his theory differed from other engine builders in that respect. There's a lot of different setups that work. I think porting is the most important part of an engine, the bolt one are for the extra power you want. Rider skill and hull setup is the #1 thing that sets people apart IMO, not engine size

 

[masterblaster]

I was referring to the 62t giving a few extra rpms up top,Im aware of art,chuckie,blue and many other builders who thought the x cylinder to be better suited to freeride,as well as power valves not being needed. I agree as well they are primarily a marketing/hype thing for free-ride applications. You can argue that case with scotti,we just have no use for x or t cylinders anymore these days...stroker for life

 

[Tommygunz]

I am a life long stroker too! Lol

 

[Vumad]

Why isn't there a good write up on why the yamaha driveline hasn't changed over 20 years??? I wish there was.

The 701 has changed, it's just the superjet that has stayed the same. It's become the 760, the 800R, the 1200, the 1200R and the 1300R. (GP700 > GP760/1200 > GPR800/1200 > GPR1300). However, putting these motors in the Superjet take development money into a ski that doesn't have a very large production or sale volume. R&D costs money. Why change something that works? They only continue to sell the ski because they make the profit in the low cost of production. Kawasaki changes their ski all the time, at least they did, but not any more, because the took it out of production. Yamaha changed the ski in 2008. Not because they had an epiphany to make it better, but because they were getting stomped by Kawi in the races. They made a minor, inexpensive change that yielded better results. If only they hadn't changed the steering cable, but they used what was on the FX1, probably to save money.

So in summary, it hasn't changed because keeping it the same is more profits than changing it.

 

[Vumad]

Large mag pump being a 148-160mm puts more load on an engine and higher compression makes the side loading worse. I wasn't saying total loss influences engine life just pointing out the extremes that people running a stroker go through to get the most power. Usually they are less concerned about longevity and that's going to affect the average lifespan of a stroker since they appeal to that type of rider more than a rec rider. Strokers can be setup to have a good lifespan with very little issues. Matt_E had his 10mil for 1-2 seasons and he said it looked brand new when he inspected it

Considering that the flywheel is the balancer that helps maintain bearing life, doesn't all lighter flywheel of any kind increase engine vibration and therefor decrease crank life? Total loss being the lightest and therefor most harmful?

 

[Vumad]

My 12mm wiener makes 19inchpower with massive stroke. If I smallen up the combustion chamber a bit I can get the rod to throw frequency back into the timing spec. That's when I run into problems with hitting the firewall though.

I'm sorry, but are we still talking about jet ski engines? That last sentence makes me think you might need to add some penicillin to your pre-mix.

 

[KTM434]

The flywheel is not a harmonic balancer/vibration dampener like you may find on a car. It's a heavy piece of steel with heavy magnets for charging and ignition signal and a ring gear for cranking the engine over. Total loss replaces the steel with aluminum and removes the magnets for charging. It still needs the same diameter ring gear to crank the engine and a pickup for ignition so they retain those parts while making it as light as possible. If anything a heavier flywheel would put more strain. When ignition occurs that piston is forced down, any resistance against that motion gets transferred to the crank bearings. The crank bearings take a lot of force every time the piston changes directions but the counterweights on the crank decrease that and that's where your balancing takes place. Although the cranks have counterweights to balance the rotating assembly you are still affecting its original design when you change compression, piston size, rod length and angle, stroke, timing advance, rev limiter etc. all these changes will affect crank life but as its been said "you gotta pay to play" and its all worth it.
Lets face it, stock just isn't good enough. I don't expect my engine to last 10-15 years, ill gladly rebuild it way before then and probably be running something different in that time frame.

 

[masterblaster]

lets summarize with pricing changes in the last yr,pretty much no brainer...https://www.facebook.com/pages/Competitive-Crankshafts/235380236498608...best thing going right now

http://www.x-h2o.com/threads/131452...m-stroker-crank-for-62T-based-motor......good info,the price has come WAY down since then as well. I have a few for less than 700!

or $900 for a SS if thats your thing..lol
http://www.teamxscream.com/products/index.php?main_page=product_info&products_id=6596
http://www.yamahapartshouse.com/oemparts/a/yam/5003a6eef870021f60a13bab/crankshaft-piston

 

[McDog]

I believe this is latest pricing.....
http://atlantispowersports.com/crankshafts-crankshafts-for-yamaha-c-2_336_408_409.html

 

[KTM434]

I believe this is latest pricing.....
http://atlantispowersports.com/crankshafts-crankshafts-for-yamaha-c-2_336_408_409.html

It really is a no brainer with those prices!

 

[masterblaster]

they get considerably cheaper than that in bulk,I have a few 8 and 10 mills for less than 700 and a few with koyo bearings for 900.

Adr is deff the best thing going in stroker cranks these days,the rods are awesome compared to what has been used in the past with some other manufactures