budget freestyle engine

[norcal ex]

if im going to be building a whole new engine i will need to buy everything. the only way i can get it to be the cheapest that is can be is have the deadline for it in december or something, that means i have all simmer/winter to look for parts. about the crank...it will need to be a newish or rebuilt one. thats one of the most important parts of a reliable engine. being cheap on that is the worst thing to do.

 

[freestylegeek]

i already have some of this stuff :

[X] cleaned stock 701 cylinder (wet jet 701 with a fresh rebuild)
[ ] 62T cases
[ ]lightened flywheel (im getting an advent so i need stock flywheel)
[ ]carbontech reeds (these dont help with performance do they? they just make it so if they break they wont destroy the engine like the stock ones will..correct?)
[X]180psi comp
[X}b pipe
[ ]twin 38s

[X]impros 13/16 cutback prop
[ ]bored nozzle
[X]stubby pump cone

will 62T cases, twin 38's and a bored nozzle really be what i want. i can tell my skill is being restricted by the engine. will they unleash the beast? i wanted to build another engine so i will have a spare to work with for a future project or if it explodes... hmmm

Hmm, from what you've listed there, you could probably build my old motor (the one that is in SJ13's boat now).
You would need:

Hot Rods Crank - $450 ish
Milled stock head - $100 to mill, do you have a stock head?
Sport Port Template - $75 (3-5 hours to port it with a dremel)
Pro-X pistons (or OEM) top-end kit - $250
Carbon tech reeds - $60 (I think)
RIVA reed spacer - $60
Stock 38's with a stock flame arrestor and manifold - $200
Lightened stock flywheel - $??

The rest of the stuff is free little things that add up.
Rough up everything on the intake up to the combustion chamber. Match all gasketed surfaces. Lightly port your cases (smooth sharp corners). Polish your exhaust manifold - Bore it out if possible.

I think you're gonna be able to make a pretty decent motor.

 

[Freestyleriverrat]

That is about what my motor will be, except Paul did all the porting (cylinders and cases) and I'm running V-force reeds. Estimated HP should be between 100-110 hp.

 

[norcal ex]

the head i have right now is an ocean pro cool head....girddled

 

[unclehulka13]

now personally i would run 61x cases and a single carb. save yourself money.
Some people swear by t cases, but ive ridden a riva motor (62t) and a head enterprises engine (61x) and by far the x motor hit harder, cleaner, and sooner. And it cost WAY less.

 

[Freestyleriverrat]

Were just the cases different or were the cylinders different as well? The cylinders would probably produce a more noticable difference as far as low end power. I've been on some stought 61x's before, I don't think that the cases are the limiting factor unless you want to keep building the motor by doing an BB kit or lamey, in which case the size of the reed valves will be the bottleneck on power.....larger valves are the reason the cases are different.

But a single carb 61x should do well and give nice controlable low end grunt.

 

[runaway]

I have a Head Enterprises 61x/61x (epoxy filled ported cases & ported cylinder) complete motor with r&d rec head, ported intake, CT reeds, new crank, Wiseco pistons and 48mm Blackjack carb for sale right now. Pm me if you want. Compression is 185/187 with a snap-on guage.

BTW: I rode this engine for a year, and I went to a big bore flat top 62t/dual carbs. Much more all over the powerband. I will never go back to x cases. I also have rode stock ported 760 cylinders with stock 44's that made better power than the Head engine.
-Ryan

 

[Matt_E]

That is about what my motor will be, except Paul did all the porting (cylinders and cases) and I'm running V-force reeds. Estimated HP should be between 100-110 hp.

Which will take a you a long way in your skills before you "need" more power. This is about what I am running.

 

[unclehulka13]

I have a Head Enterprises 61x/61x (epoxy filled ported cases & ported cylinder) complete motor with r&d rec head, ported intake, CT reeds, new crank, Wiseco pistons and 48mm Blackjack carb for sale right now. Pm me if you want. Compression is 185/187 with a snap-on guage.

BTW: I rode this engine for a year, and I went to a big bore flat top 62t/dual carbs. Much more all over the powerband. I will never go back to x cases. I also have rode stock ported 760 cylinders with stock 44's that made better power than the Head engine.
-Ryan

Unless you're talking about overall power and not about initial hit, im putting the flag up. The timing on the 760 cylinder is geared toward mid and top, so for it to hit harder, either you dont know how to tune, or you're delusional. Same with any other builders 61x, not just defending 1.

 

[GDFL]

Unless you're talking about overall power and not about initial hit, im putting the flag up. The timing on the 760 cylinder is geared toward mid and top, so for it to hit harder, either you dont know how to tune, or you're delusional. Same with any other builders 61x, not just defending 1.

I keep reading about the harder hit of the 61x's and 61t's over the 760 because of the timing ports. Has anyone ever done an actual dyno run of similar engines to substantiate this talk? I don't doubt that it's possible, but that's almost like saying a chevy 305 hits harder at x point in the power curve than a 350 (you get the point). I somewhat doubt it when people say it "feels" better because "feel" is very objective and subject to psychological error; kind of like a placebo thing. I guess all I'm asking is this: is there a pair of dyno curves that can prove or disprove this?
Garrett:reporter:

 

[Matt_E]

Actually, it's a very physical port timing issue - a 61x cylinder simply has more port timing down low than a 62T cylinder.

 

[GDFL]

Actually, it's a very physical port timing issue - a 61x cylinder simply has more port timing down low than a 62T cylinder.

Yeah, I get that part, but wouldn't the extra 59cc make up for sometihing? That's what has me questioning it. I'd really love to see a comparison. Not to prove anyone wrong or right, but just out of curiosity. I doubt there's anything out there because there are about 1 billion ways to build a motor and to have two that are similar enough to be good for semi scientific testing would be rare. "There's no replacement for displacement" or is there?:Banane01: :Banane01:
Garrett

 

[romack991]

I keep reading about the harder hit of the 61x's and 61t's over the 760 because of the timing ports. Has anyone ever done an actual dyno run of similar engines to substantiate this talk? I don't doubt that it's possible, but that's almost like saying a chevy 305 hits harder at x point in the power curve than a 350 (you get the point). I somewhat doubt it when people say it "feels" better because "feel" is very objective and subject to psychological error; kind of like a placebo thing. I guess all I'm asking is this: is there a pair of dyno curves that can prove or disprove this?
Garrett:reporter:

Its not just the bore size that is different, the 61x has lower port timing than the 760. How ports are setup play a huge factor in where the powerband is.

I see no reason why a 305 couldnt make more power than a 350 at a given rpm range if the ports are different. Its all about how the engine is set up.

 

[Matt_E]

The Extra 53cc (yes, it's only 53), do make up for something...just not at that low RPM.

 

[WaveDemon]

i have a 86mm 760 cylinder. the hit is higher than a 61x cylinder.

 

[RoyalFlush@PCB]

i have a 86mm 760 cylinder. the hit is higher than a 61x cylinder.

Tim---are you saying that it hits "harder" or the the hit comes at a higher RPM?!?

 

[WaveDemon]

Tim---are you saying that it hits "harder" or the the hit comes at a higher RPM?!?

I meant higher rpm. It hits pretty hard too. :arms:

 

[runaway]

Unless you're talking about overall power and not about initial hit, im putting the flag up. The timing on the 760 cylinder is geared toward mid and top, so for it to hit harder, either you dont know how to tune, or you're delusional. Same with any other builders 61x, not just defending 1.

I don't ride flat water, I ride surf. All my riding is not off idle, rather off a slow cruize. I am not the flat water expert. However, screwing around off idle a t cased dual carbed 760 grunts better with the proper ammout of compression than the x/x single carb.
I am a believer in displacement. Right now I have a riva big bore flat top 61x cyl/62t cases, ported and dual 44's. Kicks the Head Enterpries engines a$$, any rpm. PERIOD I don't care how you tune it.
Delusional, whatever. What engine do you own again? Lets see, right now I have a 5mm Able stroker, the flat top riva and the Head Enterprises engine. Many people have rode my ski in bolth (Head engine and Riva engine, the Able is awaiting a hull) configurations. Mike Surlin, Ross Champion, Providers, LBE, waveblaster 069, Jeremy Phillips...... They all disliked the 61x/61x engine and favor 62t cases. And my engines are all jetted by the precise instructions of the master, Magoo.

 

[unclehulka13]

the point is that the x engine hits harder off idle than the 760. Theres no one that will tell you otherwise. timing based, the x will hit sooner, and harder, because of the intake tract.

im sorry you're unhappy with the x-x motor. Lemme know what you want for it, maybe we'll make a deal. i wont need the carb though.

 

[runaway]

I understand your point. My point is for his budget its a good choice. Even my Head motor costs more than 1500 new. Boring out an x cylinder to 760 is doable and very nice, lower ports and all that, but price is an issue. I still would ride a 760 stock ported cylinder any day, its a real grunty fun motor. Just get the compression up.
I would still stay with t cases.