New BIG BORE 781 Freestyle Ported JetManiac/Blue Motor

[swapmeet]

I want to re-bump this thread and let ya'll know this engine is the bomb in my Chan. Granted its a sub 100lb hull, but it makes it jump out of the water. Literally.
I ordered my motor with carbs pre-setup from Chris and it runs forever on a kart tank. I can't see why anyone would want 44's or 46's...



@waksk8 and @bobob729 Have both been on my ski and have had nothing but great things to say about the motor.

 

[N3vrSat1sfied]

I want to re-bump this thread and let ya'll know this engine is the bomb in my Chan. Granted its a sub 100lb hull, but it makes it jump out of the water. Literally.
I ordered my motor with carbs pre-setup from Chris and it runs for ever on a kart tank. I can't see why anyone would want 44's or 46's...

View attachment 262242View attachment 262241

@waksk8 and @bobob729 Have both been on my ski and have had nothing but great things to say about the motor.

When I had mine it was on 44's and still was very conservative on fuel. These are truly great motors for the money.

 

[swapmeet]

I've been considering getting a bigger motor (because isn't that what we all do?) and i've had a hard time justifying why I need it.

 

[naticen]

Everyone is always shocked at what I am running after they ride my ski and I haven't done a thing except bolt stuff on. This Winter, I'm hoping to throw on my taper bore 38's bore my B-pipe and any other little tricks to see what it does next. I think this motor is about the last economical step before you start throwing away double and triple the price for nowhere near double the horsepower, let alone triple.

 

[stagesrt4]

I have a 781 n had a chance to ride a 771 with simular mods this weekend

hands down there was no comparison.. the 771 felt like a 701 compared to my 781

 

[Blue]

Thanks guys. Chris and I really appriciate all the positive feed back. Im really glad everyone is happy with the motors i build and jetmaniac has done a great job with the carb and electrical rebuilds and installations. Not to mention supplying great parts for all your builds. Dont forget we offer many larger engine sizes if your looking to go bigger or If you own or are looking to buy a BB 781 we can install a php 4 mm stroker crank in our BB and make it 817cc. Jetmaniac has one in his Circus now.

 

[Nobbyq]

is it a case of swapping cranks out ? and how much would it cost ? thx

 

[N3vrSat1sfied]

is it a case of swapping cranks out ? and how much would it cost ? thx

and novi 48's

 

[SpaceCowboy]

and novi 48's

you wouldn't need novi's but they wouldn't hurt lol

 

[N3vrSat1sfied]

you wouldn't need novi's but they wouldn't hurt lol

That's how Jetmaniac's is set up, and when he quoted me when I was gonna do this to my motor, the carbs were recommended.

 

[SpaceCowboy]

That's how Jetmaniac's is set up, and the quote he sent me over when I was gonna do this to my motor, the carbs were recommended.

Zack recommends Novi's for my PHP898 but he said a set of 46's would work if that was my budget

EDIT: not to derail this thread...sorry for bringing my PHP motor into the mix...I had a JM781 in my hurricane....absolutely no regrets!

 

[Informal]

Informal's BB on the way to the West Coast!

View attachment 262170

View attachment 262171 View attachment 262172 View attachment 262173

Come to Butthead.

 

[blue4776]

Swapping out the crank and domes and a little port adjustment and walla 817cc at 85mm with 2 bores left in the cylinder. No case trenching required.

 

[Blue]

Swapping out the crank and domes and a little port adjustment and walla 817cc at 85mm with 2 bores left in the cylinder. No case trenching required.

Sorry my tapatalk accidentally signed me in as my old profile.

 

[loictahiti]

And what the final price with +4 & 85 mm piston ?
Thks

 

[Blue]

Jetmanic will need to answer that question. I just build them.

 

[xixp]

Hi, does this engine run with an standard FP manifold & gasket or due to being a big more the manifold needs to be modified ?

 

[Blue]

Its best to send your FP manifold and head pipe in for porting to get the maximum power gains possible but it will run without it. I also recommend porting the PFP manifold as well.

 

[xixp]

Thanks for the reply, one more doubt once the FP manifold and Head pipe are ported do they become unusable for a non ported application? I plan to keep my stock non ported 701 as a back up so I wonder if I wont be able to use those parts any more with a non ported engine

 

[JetManiac]

Thanks for the reply, one more doubt once the FP manifold and Head pipe are ported do they become unusable for a non ported application? I plan to keep my stock non ported 701 as a back up so I wonder if I wont be able to use those parts any more with a non ported engine

Not at all, the BB mani and headpipe work well on a stock motor also.