Freestyle Big Motor Question?

[BCM]

I'm getting ready to build a budget flatwater motor. I was going to try and find a 5 or 8 mill stroker crank and a 760 cylinder and bore it out to 85 mill pistons, but everyone is telling me that the port hights on the 760 cylinder will be to high. So would it be better to us a 61x cylinder and install big bore sleeves in it, or could I use the 64x cylinder and either have it bottom decked to lower the port hights. Any help would be great. Thanks

 

[chriselmore_1]

deff use 61x but for how much your going to spend on that setup you should buy a professionally built motor used. You're just setting yourself up for dissapointment....

 

[Matt_E]

I'd ask an engine builder.

 

[chriselmore_1]

fyi one of the hardest hitting motors I've rode is a 5mill cast lamey pv motor with tl and a r&d drypipe. This motor was soooo well tuned and had the lowest pitch prop I've ever seen 7/9

 

[#ZERO]

I would use a non ported 61X cylinder to start with and the standard NW big bore sleeves because the transfer & boost ports are 2mm lower with extend floors to accommodate a 5mm stroker crank with the stock length rods. If you want to use an 8mm crank with the longer rods you'll have to find a taller aftermarket cylinder for freestyle use. Also you'll want to keep the bore size smaller than 85.5mm because the pistons will be higher than the deck surface and will require custom machined domes.

 

[BCM]

I got a good budy who ownes a jetski shop and helps me build all my motor and they have been better and better everytime, I just trying to find a good idea to bring to him.

deff use 61x but for how much your going to spend on that setup you should buy a professionally built motor used. You're just setting yourself up for dissapointment....

 

[chriselmore_1]

what's your budget? Don't forget about putting all that power to the water

 

[BCM]

Thank you, We can custom machine domes at the shop so thats not a big deal, And that sounds like a good set up to me.

I would use a non ported 61X cylinder to start with and the standard NW big bore sleeves because the transfer & boost ports are 2mm lower with extend floors to accommodate a 5mm stroker crank with the stock length rods. If you want to use an 8mm crank with the longer rods you'll have to find a taller aftermarket cylinder for freestyle use. Also you'll want to keep the bore size smaller than 85.5mm because the pistons will be higher than the deck surface and will require custom machined domes.

 

[BCM]

around $2400 for my motor set up. and I should be able to do it with that building the motor my self, power to the water, I'm using a stock pump with I think it's a 9/16 hooker prop

what's your budget? Don't forget about putting all that power to the water

 

[chriselmore_1]

I've seen some good deals on built strokers lately 2000 to 2500. You wouldn't believe what I paid for my setup...

 

[Lucaumpits]

send a PM to Jetmaniac, he has 2 big bore for sale, and that thing will stretch your sockets off

around $2400 for my motor set up. and I should be able to do it with that building the motor my self, power to the water, I'm using a stock pump with I think it's a 9/16 hooker prop

 

[chriselmore_1]

man if he sold just bb topends I would of bought one. But it's a good thing I didn't cuz I would of missed out on the deal of the century...braaaaaap

 

[Schmidty721]

man if he sold just bb topends I would of bought one. But it's a good thing I didn't cuz I would of missed out on the deal of the century...braaaaaap

What did you snag? I'm rock'n a $350 5mm stroker that I picked up last summer!

 

[chriselmore_1]

I got a lamey pv 10mill stroker motor with tl , intake and lamey 46 carbs. Got an amazing deal...

 

[munki63]

I would use a non ported 61X cylinder to start with and the standard NW big bore sleeves because the transfer & boost ports are 2mm lower with extend floors to accommodate a 5mm stroker crank with the stock length rods. If you want to use an 8mm crank with the longer rods you'll have to find a taller aftermarket cylinder for freestyle use. Also you'll want to keep the bore size smaller than 85.5mm because the pistons will be higher than the deck surface and will require custom machined domes.

Is there a particular piston he should use?

 

[waxhead]

yes use a pro-x piston.
Using the sleeves like zero is talking about is the best way to make a 5mm work on a stock cylinder.
other wise you will end up 135 degree transfers unless you run the pistons positive deck

 

[munki63]

yes use a pro-x piston.
Using the sleeves like zero is talking about is the best way to make a 5mm work on a stock cylinder.
other wise you will end up 135 degree transfers unless you run the pistons positive deck

Spacer plate not required then?

 

[waxhead]

yes you will need a spacer still but I see a lot of people using the stock sleeves with a spacer plate. It makes for a very flat engine down low and then it will hard up top.
And next to no throttle response

 

[motoman96]

around $2400 for my motor set up. and I should be able to do it with that building the motor my self, power to the water, I'm using a stock pump with I think it's a 9/16 hooker prop

Seems a bit pricey IMO. The 5 mil crank I just bought, an having Jetworks put bb sleeves in it, port it, assemble it etc. I wont even be spending that much. Call an talk to Art at Jetworks. He's the man!!