2 actually lol ok so I really need to think about this whole thing problem is I don't have a grand to drop on this right now and my ridding season starts in April. Maybe I should just run what I have though this season save up and send this off to holeshot end of season.
44mm carbs on a 701
- Thread starter miah
- Start date
waxhead
wannabe backflipper
- Location
- gold coast
Now your onto it
A pair of 44s will make the pipe hit a little harder is all. They generally use more gas because they must be tuned richer at part throttle for good response. Standard SBN44s work great and are the easiest to tune.
waxhead
wannabe backflipper
- Location
- gold coast
And now 760 carbs just jumped up again in value. Thank you very much not
I always use these things they are an awesome upgrade
I always use these things they are an awesome upgrade
- Location
- fortcollins
Don't forget that pump and prop tuning are just as important as all this motor work your gonna do
There are lots of ways to skin a cat, but for best bang for the buck low and mid range power definately switch to 61x cylinder. Stay with the dual 38s and make sure you have all the best bolt-ons including bpipe, ADA head, hooker 9/15, flow control valve, etc. Then if you have money left, get your cylinder freestyle ported by a shop with a track record of satisfied customers.
Ok so I have the 2 62t cylinders and a 61x on the way guess it's time to build a Yamaha motor for my x2 this is so confusing everyone has a different preference on what works best for them. My wife's rn superjet has the 62t/61x motor but I wanna leave it mostly stock. Just wanna put a pipe on it for her , I really appreciate everyones input even though now I'm more confused
How much do you guys charge for porting?
Why are you confused? The 61x cylinder has lower port timing for freestyle and that is what comes on all superjets from 1994-2014 for a reason. They work great in stock skis with bolt-on upgrades. They work alot better when ported and modded for freestyle.
The 62t cylinder has higher port timing and was designed for couches. The cylinder needs to be clearanced just to fit a girdle kit and modded to work with superjet exhaust manifolds. It can be modded to work but requires alot of work and mods, which do not fit with a simple, budget approach.
waxhead
wannabe backflipper
- Location
- gold coast
To be fair the 62t does not require a girdle head and its a simple case of just screwing in the helicoils to the exhaust mounting bolts you dont even need to tap them they just screw right in there.
I would say its cheaper to get a 62t cylinder to run than reliably than it is a 61x
90.5° Exhaust Port Opens
121° Transfer Port Opens
179° Exhaust Duration
118° Transfer Duration
30.5° Blowdown Time
Here are the specifications for the 62T-701 & 63M-1100 cylinder sleeves.
89° Exhaust Port Opens
121° Transfer Port Opens
182° Exhaust Duration
118° Transfer Duration
32° Blowdown Time
Here are the specifications for the 62T-760 and LA-1588 BB cylinder sleeves.
87.5° Exhaust Port Opens
120.5° Transfer Port Opens
185° Exhaust Duration
119° Transfer Duration
33° Blowdown Time
the 62t 701 cylinder is very close to a 61x, the ports just line up better. In reality the 62t std will preform like a mild port job on a std 61x
the 760 runs higher exhaust and so it may be a bit softer down low if the rest of the engine does not compliment it. Most surf port jobs will run more exhaust than this anyway but it seems alot iof people want to run lower exhaust because the internet told them it was the go.
If you measure any good freestyle engine you will find more exhaust port timing then aa stock 760. you need to spend time setting up the rest of the boat as well, ie pump
I would say its cheaper to get a 62t cylinder to run than reliably than it is a 61x
90.5° Exhaust Port Opens
121° Transfer Port Opens
179° Exhaust Duration
118° Transfer Duration
30.5° Blowdown Time
Here are the specifications for the 62T-701 & 63M-1100 cylinder sleeves.
89° Exhaust Port Opens
121° Transfer Port Opens
182° Exhaust Duration
118° Transfer Duration
32° Blowdown Time
Here are the specifications for the 62T-760 and LA-1588 BB cylinder sleeves.
87.5° Exhaust Port Opens
120.5° Transfer Port Opens
185° Exhaust Duration
119° Transfer Duration
33° Blowdown Time
the 62t 701 cylinder is very close to a 61x, the ports just line up better. In reality the 62t std will preform like a mild port job on a std 61x
the 760 runs higher exhaust and so it may be a bit softer down low if the rest of the engine does not compliment it. Most surf port jobs will run more exhaust than this anyway but it seems alot iof people want to run lower exhaust because the internet told them it was the go.
If you measure any good freestyle engine you will find more exhaust port timing then aa stock 760. you need to spend time setting up the rest of the boat as well, ie pump
waxhead
wannabe backflipper
- Location
- gold coast
the rule of thumb is 1% pump efficency is worth about 10% hp in jetboat racing.
every time you get your pump closer to the ultimate setup you get good gains.
Most people over prop there skis but the engine wants to rev. This will kill the snap of your ski more than anything
every time you get your pump closer to the ultimate setup you get good gains.
Most people over prop there skis but the engine wants to rev. This will kill the snap of your ski more than anything
waxhead
wannabe backflipper
- Location
- gold coast
The internet didn't tell me what I have felt.
The only way I know to tune a pump is to ride someones ski with your motor...that has a tuned pump...and then copy him
or spend time bending your prop, this is a good reason to have a nozzle with adjustable rings and a tacho. it makes it alot easier
That's gonna be hard cuz all my ridding buddies ride kawi 550'sThe internet didn't tell me what I have felt.
The only way I know to tune a pump is to ride someones ski with your motor...that has a tuned pump...and then copy him
Doh! You are gonna be dusting them all!
The X members will get you dang close I imagine....once you are ready....
I was lucky and rode a few skis with my motor and ultimately listened to Paul Lehr and never looked back. I would hate to have to tune a pump from scratch using those rings and multiple props...
The X members will get you dang close I imagine....once you are ready....
I was lucky and rode a few skis with my motor and ultimately listened to Paul Lehr and never looked back. I would hate to have to tune a pump from scratch using those rings and multiple props...
- Location
- fortcollins
A good starting point for your pump and somone correct me if I'm wrong, this is what I've found to best for my boat, channel cut 201 intake, un molested 9/15 hooker with no spacer which I think gives you 3mil setback, solas mag stator, standard cone, nozzle bore(taperbore)at 85mm. I've played around with about 5 different prop and cone combos and 3 or 4 intakes and found this to be my favorite, haven't messed with pump set back yet but that's next season tuning goal
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