Need Help with motor

[superjetdave]

How do i go about getting the most amount of brat out of a 650 6m6 motor. Already have a triton engineering billet head but not positive on dome size. Was told that it would increase compression so was wondering if new bigger pistons would help out as well. Any advice will help I am building my first ski.

:You_Rock_Emoticon:

91 sj sn

 

[Boris]

A pipe, any pipe other than the stock one.

Bump the timing.

Raise the rev limit.

I assume you already have a prop and intake grate ?

 

[superjetdave]

no I do not like i said this is my first build. I have done some research but still don't know what kind of prop, grate, and ride plate to go with.

 

[Mouthfulloflake]

is the engine together? or taken apart?

do things you can translate into a larger engine later, so its a LONG term investment.

lighten the flywheel, $60 or so, and helps alot, and fits a 701 engine

advance the timing, free. ( and easy to do since the flywheel is off)

ad a pipe, most 701 pipes will fit the 650 also.

compression is your freind, get a head that makes 185psi or so.

bore your pump reduction nozzle.

you can do this with a sanding drum on a drill, for short bux, and it makes a good difference in low end hit.

a LOW pitched impeller, solas concord or skat trak swirl.

I had a concord 12/15 on my 650 and it worked really well.

and of course that impeller will work with a larger engine too, so its not like wasted money.

a jet dynamics, or worx intake grate, basically any top loader type, the more aggressive the better generally.

my favorite rideplate is a astock plate with a 'D' shaped cut in the rear, really helps get the nose of the boat in the air.

 

[Boris]

There you go.

Raise the REV limit by modding your CDI, a 701 CDI or an enhancer.


That 12?15 prop worked awesome on my 650 and still does great on my 701.

 

[Mouthfulloflake]

yeah, forgot the rev limit thing.

its really only needed with a pipe, and especially with the pipe and a 12/15 impeller!

 

[orangefinger]

I have a Coffmans up for sale if you have any interest that really worked great with my 650.

 

[superjetdave]

the motor is apart right now to be cleaned. When I got it wasn't sure on how long it had been since it was ran. The water passages have a good amount of deposits in them. Will be posting pics of motor and ski later this week.

Really appreciate the info.

What about carb and intake?

 

[superjetdave]

That sounds great orangefinger but I am limited on cash right now. If you still have it a couple of weeks from now I will be definitely interested.

 

[Boris]

The stock carb and intake are good but check the reeds.

One thing to think about.
If you have the motor apart maybe it would be a good idea to pick up some cases and a cylinder and build a 701.

Nothing wrong with a 650 but if you need to spend money on it I would rather spend it on something bigger.

 

[Mouthfulloflake]

go cheap...

port the cylinder while it is apart....

if you can swing $60 or so for some 61x cases, that should help some too.

its easy to nickel and dime your self into alot of $$$ for not much motor, so do the cheap/free thigns first.

your already into about $30 worth of gaskets though, just to re-assemble.

 

[superjetdave]

Thanks guys this info really helps. I hoping to have my boat done and ready to ride by the end of March at the latest.

:Banane01:

 

[Fro Diesel]

Dave,

Sell all those 650 parts i gave you, and buy a 701. Or just put everything back together with that triton head, toss on a coffmans pipe for the time being. You need to do this cheap, so that you have enough cash to get the rest of the boat done. Sounds like you have the right idea about just getting it back together CHEAP. If you are worried about those pistons that someone painted the tops off, maybe someone has some good used ones.

You need to have this thing done by the time i am ready to ride so that i can have a tow-in if needed. Can i really count on you?

good luck buddy,
Jeff

 

[thegoldenboy]

I would also opt to go for a 701. Noticed a huge difference going from a 650 with (pipe, head, oversized pistons, rejetted) to a stock 62T 701.

Save the time and hassle, wait for a 701 to come avaliable over the winter and snatch it up.

Sell your motor for $300 complete. It will be a $400 - $500 upgrade if you get a good deal.

Much better than building a 650. Take it from me, I made this mistake last year.

 

[Mouthfulloflake]

good luck selling a complete 650 for $300 I havent, I have been un-able to sell any 650 engines so far.

I would also opt to go for a 701. Noticed a huge difference going from a 650 with (pipe, head, oversized pistons, rejetted) to a stock 62T 701.

Save the time and hassle, wait for a 701 to come avaliable over the winter and snatch it up.

Sell your motor for $300 complete. It will be a $400 - $500 upgrade if you get a good deal.

Much better than building a 650. Take it from me, I made this mistake last year.

 

[monkeyboy650]

im a retard i bought a 650 not complete for 330 and got the rest from mouthfulloflake

 

[Mouthfulloflake]

you could have bought my 701 for cheaper and already been riding!

 

[Fro Diesel]

you could have bought my 701 for cheaper and already been riding!

A 701 is the way to go. I am sooo glad i bought one for daytona. Slightly ported with a b-pipe wet jet intake it still could use some tuning.

You won't be able to hang with me if all you have is a 650 with a head. Come on Dave....make a smart purchase....there's always student loans that can be diverted into a project ski build.
:highhorse:

 

[Mouthfulloflake]

ive rocked a 650 motor for years, they are fine, and fun.
BUt as soon as I came across some reasonably priced 701 engines, I made the swap.

 

[monkeyboy650]

yah i know i screwed up but, ill do the swap next winter..... wut can i go