SN 650..need brap ideas

[SXIPro]

91 650 SN bought as stock. Over the winter, added Coffman's Sizzler(rejetted and changed N&S), bored the nozzle, lightened the flywheel, put on a 13/17 prop. Defoamed and refoamed.

Better than last year but still, compared to my modded 701 it's like a Yugo versus an AC Cobra.

So how do I get more pep? Is there a decent aftermarket head for the 650?
Is the stock CDI holding me back?

Can I have a stock 701 CDI modded to remove rev limiter and use that with my 650 electrics? I read somewhere that the stock 650 CDI has a lower rev limit than stock 701? Is swapping stock for stock worth it?

And yes, I know..it's a 650, why didn't I just throw in a 701 or 760?? Good question.

As far as the 650 goes do I just have to live with the 'you can't polish a turd scenario?"

 

[cleetus]

I have the pro tec wake up kit in mine, with rec porting, a bored nozzle, and cutback prop, and it easily runs with a stock 701. I also have the 701 cdi. I bought it like this so I cant tell what made differences, but it has been a very fun reliable boat.

 

[SXIPro]

Thanks. I never have been on a stock 701 SJ. I bought mine pretty well built up.

My son says that now the SN has at least the same brappage, maybe more than our stock Blaster, but I am not convinced. After riding the 650 yesterday and then getting back on my RN, it was like I hadn't ridden my RN in months...like I had to hold on for dear life.

 

[orangefinger]

Compression up to 180
Scoop intake grate
MSD enhancer
Lighten Flywheel

I am using the same pipe on one of my 701's and it works great, coffmans pipe is a great pipe.

 

[velocity]

Compression up to 180
Scoop intake grate
MSD enhancer
Lighten Flywheel

I am using the same pipe on one of my 701's and it works great, coffmans pipe is a great pipe.

Be careful giving compression advice. Before you go milling or anything make sure you have a fresh topend in there. Also make sure you know exactly how to get an accurate compression reading with everything on the motor and the throttle wide open. I'm sure SXI knows those things but someone else who sees this thread might not.

 

[bassman215]

I've got a used westcoast 650 head in great shape I'd sell if you want to do something as far as bumping the compression. I would have to check dome sizes for you. I have two sets of domes. One I know is pump gas, what I ran, and the other I'm not sure. I recently built a 701 for sn so I don't need the head. PM and I can get you some more details if interested.

 

[Mouthfulloflake]

mine was set up very similar.

coffman pipe
concord 12/15, jetdynamics grate.
bored nozzle
186 psi compression
msd enhancer
advanced timing
lighten flywheel

it was STRONG

 

[Scraggly]

have you tried advanced timing yet? its good for a little noticeable brappage and cheap and easy to!!
also i cant say enough about compression, it has made big improvements on the ones i have had.

 

[SXIPro]

I do think the stock CDI is holding me back a bit. The grate I have is a twin scoop style...if I remember it might be a Solas.

Advancing timing is something I have never done. Wanna school the newb on the procedure?

Thanks!

 

[afcblink]

I believe Group K has a "Formula 650" package for it, you might want to see what they'd suggest.

 

[SXIPro]

I believe Group K has a "Formula 650" package for it, you might want to see what they'd suggest.

Interesting. I always thought they were Kawi guys. I'll give it a look though. Thanks

 

[3wheelerdude]

have you tried advanced timing yet? its good for a little noticeable brappage and cheap and easy to!!
also i cant say enough about compression, it has made big improvements on the ones i have had.

Same here. 650 with prop and Coffman pipe. I could use a write up on how to advance timing safely.

 

[SXIPro]

I was reading the Group K site and they show that as part of their Sleeper kit for the 650 they do an intake manifold mod. Anyone know what this mod consists of?

 

[Kennay]

brap idea..... yea, take the 650 out and bolt a 701 in for starters, so at least the money you spend on an engine won't be pissing in the wind.

Building a 650 is like polishing a turd. Go ahead and spend 500 on a 61x 701, and keep the 650 as a back up.

 

[Scraggly]

I do think the stock CDI is holding me back a bit. The grate I have is a twin scoop style...if I remember it might be a Solas.

Advancing timing is something I have never done. Wanna school the newb on the procedure?

Thanks!

here are a couple threads on it

http://www.x-h2o.com/threads/20104&highlight=timing+advance

http://www.x-h2o.com/threads/6564&highlight=timing+advance

 

[Mouthfulloflake]

thats horseshiat carl!

IM still trying to get my 61x 701 to perform as well as my 650 did.

it has SLIGHTLY more power, and more potential, but to suggest he could simply swap a $500 61x in and make more power is absurd, I know because ive tried that, more than once.

Nothing I suggested above for modding the 650 couldnt be swapped to the 701 ( except for maybe more compression)

pipe, msd, timing, flywheel, all that stuff will swap right over to a 701.

brap idea..... yea, take the 650 out and bolt a 701 in for starters, so at least the money you spend on an engine won't be pissing in the wind.

Building a 650 is like polishing a turd. Go ahead and spend 500 on a 61x 701, and keep the 650 as a back up.

 

[SXIPro]

brap idea..... yea, take the 650 out and bolt a 701 in for starters, so at least the money you spend on an engine won't be pissing in the wind.

Building a 650 is like polishing a turd. Go ahead and spend 500 on a 61x 701, and keep the 650 as a back up.

For now, I'll keep building the 650. It's gonna be for my son and then eventually for my daughter. So it doesn't need to be the arm ripper that my RN is. If I can get some more out of it with a head and modded CDI or enhancer for cheap money, it'll be good enough for years to come for the kids.