760 cylinder

[superjetruss]

alright I just picked up a 760 cylinder for my 04 superjet with a 701 in it right now. I was wondering what else do I need to change to make this cylinder work on my ski, i already have an ada head on my 701, will this fit the 760 if I get different domes??? thanks

 

[Matt_E]

The ADA girdle head will not fit that cylinder without some modification. You'll see what I mean when you try to install it.
You will, of course, need 84mm domes, too.

The bolt holes for the exhaust manifold are bigger than 61x.

 

[superjetruss]

I have a b pipe on it to I forgot to mention, so basically I need to buy the ada 760 head and then I should be good to go? what about carbs im running stock carbs that are true bored and chokes removed, should i upgrade to bigger crbs or can I jet them bigger thanks again.

 

[wayne]

you will also need a 62t manifold or have to get some time serts for the cylinder.

 

[aqua]

you will also need to bore your case top half to accept the larger sleeves. this is more work than it is worth if you are wanting to use this for rec/freestyle. from what everyone says your 701 will hit almost as hard as that 760.

 

[LBE]

you will also need to bore your case top half to accept the larger sleeves. this is more work than it is worth if you are wanting to use this for rec/freestyle. from what everyone says your 701 will hit almost as hard as that 760.

A 62t cas will accept a 760 cyl w/o modification. A 61x case would need to be bored. The 760 rocks IMO.

 

[OCD Solutions]

"your 701 will hit almost as hard as that 760"

There's no replacement for displacement!

The real question is; Is it really that much more power that it's worth the hassle? I'm looking to gather parts for this swap as well, just not sure if it's worth it.

 

[Matt_E]

There is quite a bit of difference between 701 and 760 cyl powerwise.

Here's what you need to do:
Take a dremel to the cases so that the sleeves will fit.
Grind the extra casting off the cyl to make the ADA girdle head fit
Put inserts into the exhaust bolt holes, OR simply make the holes in the manifold bigger. I would do the latter.

"Is it worth the hassle?"

Depends on what you consider a hassle. It's a couple hours worth of work.

 

[OCD Solutions]

What about modding a set of 61x cases, pretty much the same workup or does the 760 top end fit directly on?

 

[yamanube]

I have an OEM intake off of a 760 (dual 44s) if you are looking to go up. PM me for details.

 

[onesojourner]

is there a difference in cases between the newer 701 and the 760s? I thought they were all the same.

 

[Matt_E]

There is a difference in cases. The 760 cases don't need to be modified. The 701 cases do.

The work to make it fit is identical between X and T cases.

 

[aqua]

A 62t cas will accept a 760 cyl w/o modification. A 62t case would need to be bored. The 760 rocks IMO.

so does a 62t need to be bored to accept the larger sleeves? you said it didnt then you said it did.
(edit) I see where matt posted above saying that it does require boring.

i had to have my cases bored for my bb sleeves but i think the bb sleeves might be larger than the 760 sleeves.

i have read that the 760 cyl is not much better for freestyle than a 701 since the port height is higher in the cyl in the 760 compared to the 701. but again that is what i have read.....there is alot of conflicting info on the web and you just have to try and filter through it all. i have a feeling there is a reason why people pay alot more money to turn a 701 into a 760 compared to just buying a 760 cyl.

 

[norcal ex]

you can use a 701 head... just take a grinder to the cylinder or drill the hole out largfer. you will see where.

 

[Matt_E]

See what I wrote.
The difference in off-idle hit is noticable.

I wouldn't use it for a flatwater freestyle boat to be used in competition.
But, the components are relatively cheap (compared to X stuff), can be bored to 780cc+, and has a nice beefy casting.

I am very happy with the engine I built.

 

[aqua]

See what I wrote.
The difference in off-idle hit is noticable.

I wouldn't use it for a flatwater freestyle boat to be used in competition.
But, the components are relatively cheap (compared to X stuff), can be bored to 780cc+, and has a nice beefy casting.

I am very happy with the engine I built.

so what you are saying is that even though the exhaust port roof sits higher in the cyl you still notice a substantial increase in off idle hit due to the increase in displacement. how does it compare to a big bore 61x.

 

[Matt_E]

No....I meant that the off-idle hit is noticably later in the T cylinder compared to the X cylinder.
THe only "bigbore" 61X I've ridden was a stock sleeved 84mm bored cylinder that I ported (2nd one I ever ported). It sat on ported X cases, 44SBN, B-pipe, lightened stock flywheel.
Very interesting, because my ported 760 cylinder in question here sat on ported 61X cases, stock electrics, lightened stock flywheel, B-pipe.
However, I ran a 48 Powerbomb on it and the porting was quite a bit better on that cylinder (due mostly to more experience).
So, I had two mostly identical setups to compare (even down to the same impeller!) Even the same displacement. The X cylinder hit sooner, but the T cylinder hit much nicer all around. This was most likely due to better porting and a much better carb

If I were to port another 84mm bore X cylinder, I am sure it would hit better than the T cyl. However, 84mm on stock sleeves is iffy at best.

 

[aqua]

No....I meant that the off-idle hit is noticably later in the T cylinder compared to the X cylinder.
THe only "bigbore" 61X I've ridden was a stock sleeved 84mm bored cylinder that I ported (2nd one I ever ported). It sat on ported X cases, 44SBN, B-pipe, lightened stock flywheel.
Very interesting, because my ported 760 cylinder in question here sat on ported 61X cases, stock electrics, lightened stock flywheel, B-pipe.
However, I ran a 48 Powerbomb on it and the porting was quite a bit better on that cylinder (due mostly to more experience).
So, I had two mostly identical setups to compare (even down to the same impeller!) Even the same displacement. The X cylinder hit sooner, but the T cylinder hit much nicer all around. This was most likely due to better porting and a much better carb

If I were to port another 84mm bore X cylinder, I am sure it would hit better than the T cyl. However, 84mm on stock sleeves is iffy at best.

i see......thanks for the info matt.

 

[superjetruss]

See what I wrote.
The difference in off-idle hit is noticable.

I wouldn't use it for a flatwater freestyle boat to be used in competition.
But, the components are relatively cheap (compared to X stuff), can be bored to 780cc+, and has a nice beefy casting.

I am very happy with the engine I built.

Thats what I was thinking about building with the 760 cylinder, so im better off with my 701 then?? I thought there was no replacemnt for displacement, Im just looking for more overall low end hit

 

[Matt_E]

A nicely ported 701 will hit very nicely. If that's what you've already got, go with that.

I went the 760 route because I wanted to build a second motor with nice braap on the cheap. I mostly succeeded with that.