760 Ported VS 701 Ported my opinon

[Mouthfulloflake]

and add some compression, and some ignition advance....

broken record here.

:smile:

If your motor is tuned properly it should be making good power, just not where you want it to be. You could try getting a lower pitch prop to try and make the hit come on sooner.

 

[WaveDemon]

my 86mm motor (non-sleaved 62t cyl) ran great with 2 different single carb set ups (buckshot and powerbomb). that motor needs compression (I ran 190 psi) timing advance (2-3mm at stator) and a pipe. with all that you'll have a very strong cheap motor.

be aware you are tempting deto with these recommendations, especially if your carb is not tuned well.

for years the surf sluts would run silly high compression and make sure they never went wide open for more than a couple of seconds. is all about how cheap you are and how much you want to roll the dice.

 

[guiness92]

it won't have good snap if it wasn't ported properly or tuned right.

either way (without knowing who built your motor) it won't have the snap of a team scream built motor.

There are plenty of motors out there that have just as much if not more snap than team scream. Not saying team scream doesnt kick ass, they do build an awesome motor, but there are alot of builders out there that are just as good.

Another thing to remember is, a properly built and tuned motor doesnt need high compression numbers for lots of low end snap. Ive ridden skis that have serious low end that were in the 160 170 psi range.

 

[Mouthfulloflake]

My point exactly.

the port timing of the 760 cylinder is not like we would want it, but i do think much of that can be overcome by increased compression.

There are plenty of motors out there that have just as much if not more snap than team scream. Not saying team scream doesnt kick ass, they do build an awesome motor, but there are alot of builders out there that are just as good.

Another thing to remember is, a properly built and tuned motor doesnt need high compression numbers for lots of low end snap. Ive ridden skis that have serious low end that were in the 160 170 psi range.

 

[WaveDemon]

There are plenty of motors out there that have just as much if not more snap than team scream. Not saying team scream doesnt kick ass, they do build an awesome motor, but there are alot of builders out there that are just as good.

right, the only reason I said team scream is because it was in his poll. you could have substituted any reputable builder.

 

[Kennay]

My point exactly.

the port timing of the 760 cylinder is not like we would want it, but i do think much of that can be overcome by increased compression.

It can! :headbang:

I love this motor so far, and it's stock internally as stock can get. A bit of a lightswitch, but it's really rich on the bottom, but I think that is mostly a clean out hit or something. Also I haven't messed with the water inj. settings at all or nozzle diameter either.

 

[Mouthfulloflake]

whats your indicated cranking compression and altitude kennay?
Hell lay out your whole set up.. timing, carbs... all of it.

help Chris out here, and ME.

im a year behind him building a nearly identical engine...

It can! :headbang:

I love this motor so far, and it's stock internally as stock can get. A bit of a lightswitch, but it's really rich on the bottom, but I think that is mostly a clean out hit or something. Also I haven't messed with the water inj. settings at all or nozzle diameter either.

 

[SUPERTUNE]

I Voted!:wavey: But I'm probably a bit biased...

 

[Kennay]

Here she goes:

Single channel total loss @ 28 degrees static timing, max rev limit for now is at 8000 and it starts the retarding at 5000. Better safe than sorry for now

ADA Girdled head...Cranking compression @ whatever level it is in Montgomery, Alabama was 200 in one cylinder, and 205 in the other on 35cc domes on a stock 64x cylinder. Initially at sea level before running it, I was getting roughly 180ish. At Charles house I used a snap on, so I trust it.

Type 4 Drypipe with Jetworks ECWI kit.

Skat Swirl 12/17 with the stock cone and 61x nozzle at right at 81mm or whatever the stock metal nozzles are at. Nozzle and impeller is going to change soon more than likely. It revs fast as hell, but Charles and I both don't think that super steep prop and 81ish' mm nozzle is going it any favors. We shall see....
Dual 44mm Blackjacks with Prok's. For now they are running with a 130 pilot and a 110 main, soon to be a 105 main with some adjustments to the arm at the needle and seat

And thanks to Crammit, it runs pretty ********ing good.

I am glad I really followed his TL install instructions with the soldering everything, using weatherpacks, and using the adhesive lined heat shrink he pointed me towards. I rode in saltwater today and didn't even get so much as a hiccup, and I was subbing it and it was rolling over in the water a lot. Everything was soaked inside.

And also as of now I can say it was pretty damned good on fuel. I rode for about an hour and forty five minutes earlier, and it was showing no sign of running out. I pulled the hood a couple times to check on things, but didn't think to note the fuel level.

For a budget motor, I'd do it again in a heartbeat. Over the winter I am sending the motor off to Jetworks for a BB 61x cylinder to come into play though. There is nothing wrong with the 760cyl I have, I just would rather using a 61x to BB and then port to the max like I was planning to do with the 64x cylinder I have now.

Crammit is running a 760 cylinder in his superstock, and that sum bitch is a handful. Bottom end galore... though I do admit, it comes on a little later in the RPM range, but with how quickly that thing climbs rpm's, it very very useable. I liked it a lot.


tis a work in progress, and I will keep you updated.... DEFINATELY get total loss.... even at 5/8-3/4 throttle, you can blip the throttle just as quickly as it does in the meat of the rpm range. Tis rather awesome.

 

[orangefinger]

Chuck.....hahaha thats a good one....

Hey lets get this started I have all the parts together just gotta go on a quick vacation back august 4th and will send you everything I have....62t/61x , dual 46's , kawi reed cages, etc etc

To answer other questions

- Stock pump, 10/16 7mm Hooker ( made a huge difference from what it was before ) WW cone, no bored nozzle...didnt hurt in the 701 either.

- No timing advance, am I missing out on something ??

- I would like to run pump gas therefor my compression is currently at +- 180 is that too low ?

 

[Kennay]

~170ish is what most would consider safe for straight 93. I've done a metric ******** ton of research on the subject. I finally said f it, bumped up the compression, and have settled into the race gas deal. It's not very bad at all considering how close 93 and Renegade 110 here locally are price wise.

 

[Mouthfulloflake]

thanks for the breakdown Kennay.

and orange finger,

I think you could run some timing advance as low as your compression is, and still be pretty safe.

it helps make it snappy.

 

[Crab]

It can! :headbang:

I love this motor so far, and it's stock internally as stock can get. A bit of a lightswitch, but it's really rich on the bottom, but I think that is mostly a clean out hit or something. Also I haven't messed with the water inj. settings at all or nozzle diameter either.

Try turning it off, killed all the power on mine when testing last weekend.

 

[Kennay]

Try turning it off, killed all the power on mine when testing last weekend.

Killed the power, or smoothed the hit down?

 

[orangefinger]

Update

-Stock Flamerrestor removed, aftermarket installed.>> MORE AIR DUE TO LOW ALTITUDE

- New jetting specs Main 130 ( down from 135 ) Pilot 120 ( down from 122.5 )
N/S 1.5 ( same ) Gramm spring all same same..

High and Low screw 1-0.75/1-0.75

- Custom Air intake also darins water down to bottom of hull..

RUNS MUCH MUCH BETTER.....but still could /can /should do more

>> Getting 29cc Domes, compression check and might have to have them amachined to 30cc, current compression with 31cc Domes arround 170-175..

I want to keep it at PUMP GAS therefor 185 max I think.. ??

 

[Fro Diesel]

I used to like people who think like you. my single carb 86mm 62t cyl ripped.

:thinkingat is a big freaking carb.

 

[Kennay]

a single carb (Of undetermined size) on his 86mm bore 62t cylinder