- Location
- North Carolina
I know the drive my be a little long (ha ha) but your welcome to ride it anytime.
Freestyle Looking for 62t 760 freestyle specifics 64x Decking Porting
- Thread starter Sasquachcrap
- Start date
- Location
- California
Haha thanks man but ya I'm in California so don't count on it! Haha. Gonna hang on to my 760 as a backup plan / option for now...worst case scenario it's an immaculate bottom end already opened up for a big bore top end
ItsRixter
SoCal Wav Jumping shiznit
- Location
- Sunny Diego
Group K has a service to do this. Since you are getting new sleeves you can "Go Big" with 849cc 
The Short Version
The 845cc Kit and Performance
Simple put, the Group K Super Jet 845cc Big bore kit is the most brutally powerful 91 octane engine package available anywhere for the Yamaha SuperJet engine platform. It is built to be simple, reliable, and offer instant acceleration that is unmatched by any other SuperJet engine Mod….. It is the ultimate Free-style engine package.
The 845cc Kit includes the following:
Cylinder machining, re-sleeving, boring and sizing
Full Cylinder Porting (Freestyle Specification)
Cylinder-head modification with cooling upgrade
Exhaust manifold installation and cooling upgrade
Crankcase boring (to accommodate larger cylinder sleeves)
2 – 88.5mm Group K Pistons (piston, pin, rings, & clips) (89.0mm also available)
Top end gasket set
3Bond 1211 sealer
The Specific Parts Needed for the 845cc Upgrade
Cylinder – This modification requires the use of a 62T (701 Raider) or 64X (760) cylinder core. The stock 61X cylinder is a thinner wall casting that cannot accommodate the 845cc sleeves.
Head – An unmodified stock OEM 62T (1996 or later SJ) cylinder head core must be used. We cannot use 61X (701) or 760 head cores. “O” ring heads cannot seal on this bore diameter, and cannot be used.
FPP Exhaust Manifold & Head-Pipe - The exhaust port location of the 62t/64X cylinders is very different from the stock 701cc 61X casting. The 845 requires the use of an FPP “760” exhaust manifold, or modification of your 61x FPP manifold. For an additional charge, Group K can modify your FPP 701 manifold to properly fit the 760 bolt pattern and exhaust port locations. We must have an exhaust manifold & mounting bolts to install for final bore sizing of the 845 cylinder.
We need your FPP head-pipe & manifold to enlarge the inside bore diameters to 48mm. Doing this mod requires special fixtures, and we strongly advise against attempting this mod yourself.
Top Crankcase – The top crankcase must be machined to accommodate the larger diameter sleeves of the 845 Kit. No other lower end mods are required.
Mandatory Accessory Modifications
FPP Pipe with the “Limited” chamber Body (not the mod chamber)
FPP manifold & head-pipe inside diameter increase
Group K Modified dual 38mm carbs, or stock oem 760 44mm carb-set (rejetted)
Flame arrestor adaptors & Pods with Outerwears
“Half Girdle” kit
Rev limiter Modification
Re-Pitched Solas 13/17 Concord Impeller
The Short Version
The 845cc Kit and Performance
Simple put, the Group K Super Jet 845cc Big bore kit is the most brutally powerful 91 octane engine package available anywhere for the Yamaha SuperJet engine platform. It is built to be simple, reliable, and offer instant acceleration that is unmatched by any other SuperJet engine Mod….. It is the ultimate Free-style engine package.
The 845cc Kit includes the following:
Cylinder machining, re-sleeving, boring and sizing
Full Cylinder Porting (Freestyle Specification)
Cylinder-head modification with cooling upgrade
Exhaust manifold installation and cooling upgrade
Crankcase boring (to accommodate larger cylinder sleeves)
2 – 88.5mm Group K Pistons (piston, pin, rings, & clips) (89.0mm also available)
Top end gasket set
3Bond 1211 sealer
The Specific Parts Needed for the 845cc Upgrade
Cylinder – This modification requires the use of a 62T (701 Raider) or 64X (760) cylinder core. The stock 61X cylinder is a thinner wall casting that cannot accommodate the 845cc sleeves.
Head – An unmodified stock OEM 62T (1996 or later SJ) cylinder head core must be used. We cannot use 61X (701) or 760 head cores. “O” ring heads cannot seal on this bore diameter, and cannot be used.
FPP Exhaust Manifold & Head-Pipe - The exhaust port location of the 62t/64X cylinders is very different from the stock 701cc 61X casting. The 845 requires the use of an FPP “760” exhaust manifold, or modification of your 61x FPP manifold. For an additional charge, Group K can modify your FPP 701 manifold to properly fit the 760 bolt pattern and exhaust port locations. We must have an exhaust manifold & mounting bolts to install for final bore sizing of the 845 cylinder.
We need your FPP head-pipe & manifold to enlarge the inside bore diameters to 48mm. Doing this mod requires special fixtures, and we strongly advise against attempting this mod yourself.
Top Crankcase – The top crankcase must be machined to accommodate the larger diameter sleeves of the 845 Kit. No other lower end mods are required.
Mandatory Accessory Modifications
FPP Pipe with the “Limited” chamber Body (not the mod chamber)
FPP manifold & head-pipe inside diameter increase
Group K Modified dual 38mm carbs, or stock oem 760 44mm carb-set (rejetted)
Flame arrestor adaptors & Pods with Outerwears
“Half Girdle” kit
Rev limiter Modification
Re-Pitched Solas 13/17 Concord Impeller
- Location
- Mesa, Arizona
I am curious how this all turned out as well. I have a motor that is an odd duck thrown together by a buddy and I have been tuning it now for awhile. No porting on my 760 cylinder but I think that is gonna be next.
Great thread..tons of info here.
Great thread..tons of info here.
- Location
- North Carolina
Ended up going back to standard jetting 115 pilot 130 mains about 28 pounds of pop off... ski will pull your arms off. I am extremely happy with the set up. I did a plug chop and here are the pics. One needs a little more fuel the other a little less
- Location
- North Carolina
I gave it a try and really wanted it to work but it just didn't hit as hard and seemed like it burned a bit more fuel.
- Location
- Mesa, Arizona
So can you do just a quick recap of what you did.
I know your milled the cylinder .65...is that right? Than had the domes ajusted the same? or ? I know you did your own custom port work on the cylinders and the cases. Painted the motor... Anything else? Are the reeds stock, you running the stock 44 mm carbs, stock electronics?
Just trying to get the full on idea of what you have here.
I know your milled the cylinder .65...is that right? Than had the domes ajusted the same? or ? I know you did your own custom port work on the cylinders and the cases. Painted the motor... Anything else? Are the reeds stock, you running the stock 44 mm carbs, stock electronics?
Just trying to get the full on idea of what you have here.
- Location
- North Carolina
Stock bore 760
Milled the cylinder base .065
ADA head I don't remember the dome size. Recut for.060 squish and 200 pounds of compression.
Cylinder ported by me.
Cases ported by me. I didn't fill the fingers.
Vf3 reeds stock manifold with cross over filled.
Stock dual 44 stock air box with one screen
Stock 650 stator and flywheel. Stock coil.
MSD enhancer. 0 degrees static timing.
Riva freeride pipe.
Aluminum water box from a blaster 2 I cut up to make fit in the sj hull.
Running 100 ll av ga and castor 927.
9/15 prop ( might go to a 10/16).
Stock pump with no mods.
My next mods might be 0 flywheel, mag pump bore the nozzle and freestyle pump cone. There is definitely more vibration in the low rpm's then from the 650 or 701 but not as bad a a 1000 I have ridden.. I attribute this to the timing advance from the msd. Can't wait for an aftermarket hull.
Milled the cylinder base .065
ADA head I don't remember the dome size. Recut for.060 squish and 200 pounds of compression.
Cylinder ported by me.
Cases ported by me. I didn't fill the fingers.
Vf3 reeds stock manifold with cross over filled.
Stock dual 44 stock air box with one screen
Stock 650 stator and flywheel. Stock coil.
MSD enhancer. 0 degrees static timing.
Riva freeride pipe.
Aluminum water box from a blaster 2 I cut up to make fit in the sj hull.
Running 100 ll av ga and castor 927.
9/15 prop ( might go to a 10/16).
Stock pump with no mods.
My next mods might be 0 flywheel, mag pump bore the nozzle and freestyle pump cone. There is definitely more vibration in the low rpm's then from the 650 or 701 but not as bad a a 1000 I have ridden.. I attribute this to the timing advance from the msd. Can't wait for an aftermarket hull.
Half flip95
Formerly pondracer95
- Location
- Lake Havasu City AZ
the one that needs more fuel... give it more fuel?
the one that needs less fuel.. give it less fuel?
baby turns on the knobbies
the one that needs less fuel.. give it less fuel?
baby turns on the knobbies
- Location
- Mesa, Arizona
Are you running a hooker 9/15? I have a 10/16 I was considering swapping for a 9/15. Maybe we can work something out on that. You will not be dissapointed with the zero flywheel...was a great improvment over stock.
- Location
- Mesa, Arizona
Cut up your square like I did..It rides like a freeride rikter.
- Location
- North Carolina
Pm me and we will talk about the prop.
Quinc
Buy a Superjet
- Location
- California
Bump! Did you get her dialed in?
- Location
- North Carolina
It's pretty dang close. I was turning on the screws when you commented. I'm more or less done until I get my prop reconditioned And a mag pump in it. It feels like it slips the prop pretty good off the bottom. Plug color is still un even between the two but it runs pretty sweet, and it's getting better every ride.
- Location
- North Carolina
Also acquired a msd total loss so can't wait to get it installed. Then the tuning will start all over agian!
davidescu_radu
sea riders
- Location
- Constanta,Romania
Hi
I*m from Romania and done allmoust same as you and is working good enough for me till now - only that I have magnum pump with 2008 sj impeller
- Location
- Mesa, Arizona
Do you know how much was taken off the domes? I am doing this same project.
- Location
- North Carolina
I don't know. Chuck at CPT cut the domes. After assembly I checked the squish. Both were dead on .060. You could cut the base then assemble the motor to check the squish. Then just cut whatever you need out. I think the domes were around 39cc but I really can't remember. If you buy the domes from chuck I think he will cut them for cheap!
- Location
- Mesa, Arizona
Once I get the cases back I'll port and assemble. I had to have them bored to fit the larger sleeves. Plus I still have to tap and add a second pulse fitting for my dual 44's. Thanks for the photo btw.