New BIG BORE 781 Freestyle Ported JetManiac/Blue Motor

[Informal]

Finally got it in the water yesterday ,didn't get to ride near as long as I wanted to.

Completely impressed so far, recommended tuning specs were $$ right out of the gate.
It pulls so damn hard!


Thanks JM/Blue

 

[JetManiac]

B.Mag's new BB781 for winter hull build

 

[JetManiac]

@B.Mag

 

[Nobbyq]

how much are the 937's cc and is it just crank swap over in the jm781 ?

 

[meucarango]

781 Big Bore Power

View attachment 153219View attachment 153220View attachment 153221

These motors RIP hard! I have been running one of these in my surf freak and am stoked with their performance. Blue has been refining the sleeve and porting design on this motor for years now and it is right on the money.

View attachment 153225View attachment 153226View attachment 153227

These beautiful Big Bore motors are newly built 62t/61x (same as RN '96-'11) 781cc freestyle motors ported and built by Blue/JetManiac. They designed to offer the most freestyle low end power for the best big bore value.

62t cases- freestyle big bore ported and epoxied intake and front stator areas, cases bored to accept big bore sleeves

61x cylinder- freestyle big bore ported, new JetManiac custom Big Bore sleeves installed and bored to 84-85.5mm, exhaust/head decked

New Pro-X top end with new pistons, rings, and wrist pin bearings
New US quality gaskets
New rebuilt/SBT crank with 1 year unconditional warranty
(have options for hotrods or new oem cranks also)
New OEM crank seals
New carb jets and springs for oem 38's included, and carb tuning specs included
Cases, cylinders, and bedplates (clearanced for bpipe) are sandblasted and then bead blasted, painted and baked on beautiful semigloss black finish

Video here:

These motor are designed to work well with stock dual 38mm carb setup and jets, springs, and carb tuning specs are included. (Of course, JM BB will work well with larger carb setups like 46's or larger.)

ADA head with custom ADA/JetManiac domes and complete intake/carb setup package also available.

*We can also rebuild your motor into one like this or trade-in your core motor (crank, cases, cylinder) with usable parts for approx. 400. credit off this motor.

Short block $2680.

(Outright purchase with no core required)


View attachment 153228

781 Big Bore Power

View attachment 153219View attachment 153220View attachment 153221

These motors RIP hard! I have been running one of these in my surf freak and am stoked with their performance. Blue has been refining the sleeve and porting design on this motor for years now and it is right on the money.

View attachment 153225View attachment 153226View attachment 153227

These beautiful Big Bore motors are newly built 62t/61x (same as RN '96-'11) 781cc freestyle motors ported and built by Blue/JetManiac. They designed to offer the most freestyle low end power for the best big bore value.

62t cases- freestyle big bore ported and epoxied intake and front stator areas, cases bored to accept big bore sleeves

61x cylinder- freestyle big bore ported, new JetManiac custom Big Bore sleeves installed and bored to 84-85.5mm, exhaust/head decked

New Pro-X top end with new pistons, rings, and wrist pin bearings
New US quality gaskets
New rebuilt/SBT crank with 1 year unconditional warranty
(have options for hotrods or new oem cranks also)
New OEM crank seals
New carb jets and springs for oem 38's included, and carb tuning specs included
Cases, cylinders, and bedplates (clearanced for bpipe) are sandblasted and then bead blasted, painted and baked on beautiful semigloss black finish

Video here:

These motor are designed to work well with stock dual 38mm carb setup and jets, springs, and carb tuning specs are included. (Of course, JM BB will work well with larger carb setups like 46's or larger.)

ADA head with custom ADA/JetManiac domes and complete intake/carb setup package also available.

*We can also rebuild your motor into one like this or trade-in your core motor (crank, cases, cylinder) with usable parts for approx. 400. credit off this motor.

Short block $2680.

(Outright purchase with no core required)


View attachment 153228

Whats the price to take my limited 701 setup up to one of these 780's....? All parts in my current setup are in perfect condition,no send cranckshaft motor is 2008 year old. Thanks for the info. send ARGENTINA ?

 

[Blue]

Hopefully Jetmaniac answered your question if not PM him for a quote. Thxz

 

[JetManiac]

Erik Y's blownup 701 is reborn as a new BB781!

 

[Chris Allman]

got any pics of my black 781 carter b picked it up awhile back its going in this hull

 

[JetManiac]

got any pics of my black 781 carter b picked it up awhile back its going in this hull

Yes will find them

 

[Chris Allman]

anyone have any water intrusion issues with there 781 motor?

 

[Yami-Rider]

anyone have any water intrusion issues with there 781 motor?

You can run stock carbs/airbox with these motors, so water intrusion isn't an issue.

 

[Chris Allman]

motor is running stock carbs and airbox and runs ok as long as you don't cut it off more than 30 min or so

step 1 Im flushing the motor on the hose for about 30 seconds, while running and blipping throttle
step 2 running the motor with no water up to 20 seconds, revving it out a couple times to make certain the pipe is dry
at this point it will restart no problem...
after 30min or so of sitting it will not restart at all and the plugs will be wet.
but if I pull the plugs before I try and restart it and dry them off it fires right up.
I have only run the motor thru about 2 tanks and already have scarring in the cylinders

 

[Nobbyq]

funny i find mine never starts unless i put in new or very cleaned plugs , maybe a jcarb issue though

 

[Blue]

I believe your problem is your pipe. Its an older pipe and the manifold could be warped or pitted even cracked allowing water to leak by. I see this all the time when people send me there pipes to port. The older they are the worse they seem to be. The headpipe screws have been drilled out and if not done properly would allow large amounts of water into the pipe which could go backwards into the motor. The engine was making 195 psi on both cylinders so the orings are not leaking or it would not make that much compression or it would be lower in one cylinder.

 

[JetManiac]

motor is running stock carbs and airbox and runs ok as long as you don't cut it off more than 30 min or so

step 1 Im flushing the motor on the hose for about 30 seconds, while running and blipping throttle
step 2 running the motor with no water up to 20 seconds, revving it out a couple times to make certain the pipe is dry
at this point it will restart no problem...
after 30min or so of sitting it will not restart at all and the plugs will be wet.
but if I pull the plugs before I try and restart it and dry them off it fires right up.
I have only run the motor thru about 2 tanks and already have scarring in the cylinders

This is not the place to discuss problems with your build. These problems are not caused by the motor but from problems with your builder's installation and we are working with your local shop to fix them already.

 

[mike b]

Get this back by saying great motor right here! My friend had his motor sit for a yr, fired right up and makes ridiculous power. Old plugs too, Not temperamental at all for him!

 

[Chris Allman]

Yea Im sure i will be thrilled with it, lots of good feedback on the 781 thats why i picked it in the first place

 

[JetManiac]

BB in stock and ready to ship.

 

[Swallen]

BB in stock and ready to ship.

Is it possible for me to send my complete motor and you do the work and tune it and send it back so I can bolt it in and go? If so, how much? Have stock SBT engine with ADA Head and B pipe.

 

[Yami-Rider]

Is it possible for me to send my complete motor and you do the work and tune it and send it back so I can bolt it in and go? If so, how much? Have stock SBT engine with ADA Head and B pipe.

Jetmaniac can give you core fee for your old motor towards a new one. See first pg on this thread for pricing.