701 question

[sqwidget]

So i have a stock sj650 motor and i want to convert it to a 701. my friend has a 701 with a stock 650 case with 61x cylinders. so thats what im thinkin that i wanna do also, my question is, can i just buy 61x cylinders, pistions and head and just bolt it right on and go?

 

[Waternut]

I think you have to bore out your case slightly to accomodate the increased sleeve diameter but otherwise the cases are the same. A 61x case is still a 6m6 lower half.

 

[chips]

so how hard is it to bore out the 650 case?

 

[lvfreestyle]

clearance

just go slow and steady grinding at the cases with a air die grinder until you sneak up on a close fit...takes forever with a Dremel, but is possible

 

[sqwidget]

so no need to pay anyone to bore it out for me?

 

[lvfreestyle]

so no need to pay anyone to bore it out for me?

If you have the cash, then do it....but you also have to wait on them. It's always good to know your motor in and out

 

[snowxr]

A machine shop can do it. I can do it on my verticle mill pretty easy.

 

[sqwidget]

what about the carb, will that work too?

 

[ADDict]

I'm no expert, but I was told by an expert, than your better off switching to the 61X cases, or better yet 62T cases.
He told me the difference is very noticeable going from a 701 cylinder, on 6m6 cases, to a 701 cylinder, or the 61x or 62t cases.
I know the bottom half is the same, but there must be a lot more to the top. Again this isn't from personal experience, just told this by my builder when I was looking to do the same. You can pick up X cases cheap enough, and your crank will be fine as long as it's not ragged out.
And yes the carb will work. They are a little different from what I've been told, something about the 650 carb has one less fuel circuit that the 701 carbs, 3 instead of 4? Someone else can back that up, not 100% sure.

 

[lvfreestyle]

650 to 701

I'm no expert, but I was told by an expert, than your better off switching to the 61X cases, or better yet 62T cases.
He told me the difference is very noticeable going from a 701 cylinder, on 6m6 cases, to a 701 cylinder, or the 61x or 62t cases.
I know the bottom half is the same, but there must be a lot more to the top. Again this isn't from personal experience, just told this by my builder when I was looking to do the same. You can pick up X cases cheap enough, and your crank will be fine as long as it's not ragged out.
And yes the carb will work. They are a little different from what I've been told, something about the 650 carb has one less fuel circuit that the 701 carbs, 3 instead of 4? Someone else can back that up, not 100% sure.

That's true, but if you are going to go through all that work, then go up to a minimum 760, especially if you weigh over 130lbs....701s only have enough power for the surf

 

[DBuckner41]

That's true, but if you are going to go through all that work, then go up to a minimum 760, especially if you weigh over 130lbs....701s only have enough power for the surf

I weigh little over 200lb and my fx 1 running almost 190psi comp. pulls my ass up out of the water although a stock fx 1 (701 61x) my buddy has one takes a little longer. I would go for the 760....

 

[lvfreestyle]

I weigh little over 200lb and my fx 1 running almost 190psi comp. pulls my ass up out of the water although a stock fx 1 (701 61x) my buddy has one takes a little longer. I would go for the 760....

any ski will eventually get up, get on plane, i just think it's a lot work for little improvement, just a little more work to have much more power, i would save the time, effort, money for a bigger motor, but that's just me. .

 

[sqwidget]

anyone know if the stock carb will work?