Super Jet 701 motor mods

TheCoz43

Jet Surfer
Location
Pismo Beach, CA
If you blew the motor you already need to bore it. Higher compression may mean that you will need to run a higher octane gas, more expensive and harder to find. An ADA head with 35cc domes you can run regular gas. Might as well port it too like wanderer said. Jet maniac has nice package deals, where you send him your blown cyl and he sends you a new one that is ported if you like with pistons and gaskets. Ask him for advice. Also try to figure out why your motor blew. Gas/oil mixture, clogged filter in the carb, ect.
 
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i have been having trouble with it after i put the motor in the new hull, i put factory pipe back on and rebuild the carbs i am running 50:1 mix and i cant figure out how to get the carbs tuned right. im pulling the motor tomorrow and see when really happen. i pulled the plug and it was all beat up along with the head of the piston. my question to you is what would be the highest compression but can run off 93. i will look at the jet maniac deals. i will upload pictures later
 

Roseand

The Weaponizer
Site Supporter
Location
Wisconsin
35cc domes/185 psi with limited wot runs. You never know the quality of 93 octane. Hence the reason I run 4 gals of premium to 1 gallon of race gas just to be safe on my 180 comp 35cc domes setup
 
Sbt has a stock motor for 500$ with one year warranty that i think about doing. the bearing that go between th erod and the crankshaft fell apart and froze the rod from turning.
 

stagesrt4

see ya out there
Site Supporter
Location
St Charles IL
35cc domes/185 psi with limited wot runs. You never know the quality of 93 octane. Hence the reason I run 4 gals of premium to 1 gallon of race gas just to be safe on my 180 comp 35cc domes setup
no need for that, unless you have money to burn

my X2 granted is stock timing but im running 190psi compression with tons of WOT runs on 93 octane... 0 detonation


n I also let every noob on the river ride the ski, so she ingests a ton of water on top of it
 
Life begins at 180psi for 701s, depending on where your static timing is set, 93 is safe all day if its stock with stock cdi or even a msd, what pipe are you running? You said a factory pipe but which one? Type 4's and 9's produce way higher rpms than a b-pipe limited or mod. Your bank usually decides what mods to do, there are many things you can do for a reasonable amount that can really make a difference and are usually easy to do
 

Roseand

The Weaponizer
Site Supporter
Location
Wisconsin
no need for that, unless you have money to burn

my X2 granted is stock timing but im running 190psi compression with tons of WOT runs on 93 octane... 0 detonation


n I also let every noob on the river ride the ski, so she ingests a ton of water on top of it
Advice from zack from php said it's cheap insurance. And there's a race gas pump about ten minutes from where I ride so I get my gas there and it's only 3 bucks more per 5 gallon mix... Totally worth it imo
 
since it seems like the best thing for me to do is rebuild the motor myself. What would be a good complete rebuild kit for the 701, the cylinders are going to need to be bored. i want it to have little more punch but still be able to run on pump gas and run the stock pipe.
 
If you want more punch the first mod you should do is a pipe, you'll notice a huge gain with a bone stock motor in my opinion its the first mod you need to do with a 701
 
what are good places to get cranks that are quality? I am going to buy 61x jugs and a top end rebuild kit for 250$ and buy a new crank so i wont have to worry about the crank later down the road.
 
I think Jet maniac has stock rebuilt cranks, sbt's can be a crap shoot especially if your gonna bump up compression. If your looking for just a bit more snap for cheap, advance your static timing 3mm, have your flywheel lightend by Zero, bore your exit nozzle to 85mm and set compression at 180. Also prop choice is key as well, hooker 9/15 is usually the prop of choice for most yamaha's, Pipe will make the biggest change but can be pricey.
 
Location
Delaware
WSM is junk.. almost everything they offer is.

JM does SBT cranks, he could do other, but for a pump gas 701 that's all you really need. SBT crank with ProX, OEM, or Wiseco pistons is basically a time proven setup. Just be sure to use the wrist pin bearings from the pistons vs. the ones provided by SBT with the crank.
 
Location
Delaware
So your saying to buy a jet maniac crank. also how do i advice the timing. zero the flywheel and bore the exit nozzle? Still learning as i go
Timing is setup but advancing the stator under the flywheel when you install. You only need to move it two degrees (can't remember if it's cw or ccw), do a search and you'll find more on this.

@#ZERO is a member here that does flywheel lightening and can bore the exit nozzle. He has a post in the classifieds on the details of his service.
 
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