760 cylinders on 6m6 cases?

[Captain PegLeg]

Is it possible? Wantin to put 760+ bore on my couch.

 

[jetski9010]

I am wondering the same thing. I am starting a build for a friend of mine with a 650 superjet. His ski is super clean and I would like to keep as many parts as I can and keep the price down. I am thinking of getting some 61x cylinders have jetworks put 760 sleeves and port them and then use th 6m6 cases. I would have jetworks port the cases and maybe blackjack the stock 44 carb. Does this setup sound like it will work or is there no way to get this 6m6 cases to perform. This is for a freestyle setup.

 

[Matt_E]

have jetworks put 760 sleeves and port them and then use th 6m6 cases

That would be wasted money and potential, imho.
You might ask Art @ Jetworks what he thinks, but I think that it shouldn't be too difficult to sell the 6M6 cases and put another fifty towards at least 61X cases.
The 6M6 cases have a very restrictive intake tract.
Are you really going to drop the dough for a ported bigbore 61X cylinder and then strangle the thing with 650 cases? :dunno:

 

[jetski9010]

That would be wasted money and potential, imho.
You might ask Art @ Jetworks what he thinks, but I think that it shouldn't be too difficult to sell the 6M6 cases and put another fifty towards at least 61X cases.
The 6M6 cases have a very restrictive intake tract.
Are you really going to drop the dough for a ported bigbore 61X cylinder and then strangle the thing with 650 cases? :dunno:

yea you might be right. I was hoping that with a pro porting the 6m6 cases they would work good. Now i have to figure out if I should get 61x cases and stick with the 760 build or just big bore theh 6m6 cylinders and try to make the best of 701.

 

[Matt_E]

Think about what you're getting for your money.
For the same money it would cost to big bore the 6M6, you could have a 701

 

[Motorheads5]

GroupK has some magic for what you are asking about.

 

[jetski9010]

yes you are right for around the same price. But like I said before this guys ski looks so nice it looks like it under warrenty still. So if I could use his old motor for the build I would like to do that. Also the group k big bore kit says it will outperform a stock 701 and come real close in power to a modified 701. For $880 thats not to bad.

 

[kevbo]

Bore your 6m6 cases, use the stock carb, and have fun. The difference between a 6m6 and 61X case is no more than 1mph. Adjusting your pump load will make 10X the difference in performance.

 

[jetski9010]

Bore your 6m6 cases, use the stock carb, and have fun. The difference between a 6m6 and 61X case is no more than 1mph. Adjusting your pump load will make 10X the difference in performance.

Thats what I was hoping to hear. I am not looking for peak water speed I just want it to hit hard off the bottom.

 

[snowxr]

You will need to bore the top of the 6m6 case to make 61x or 760 cylinders fit. The 6m6 intake is only slightly smaller than the 61x, and there are dual 38 and dual 44 manifolds around for the 6m6 cases. It will run fine. Just have realistic expectations.

 

[jetski9010]

You will need to bore the top of the 6m6 case to make 61x or 760 cylinders fit. The 6m6 intake is only slightly smaller than the 61x, and there are dual 38 and dual 44 manifolds around for the 6m6 cases. It will run fine. Just have realistic expectations.

I was going to have jetworks build the motor so he can bore the cases to fit the cylinders. I know about the dual intakes out there but I was hoping to get away with keeping the single 44 and jet having art blackjack it.

 

[snowxr]

It sounds like you're spending your $$ in the wrong places. Pay a pro to big bore a 61x and spend money on modifying the carb then assemble the motor. But you are using a 44 and the most restrictive cases? Doesn't make sense to me. Why not run the 61x at current bore, and spend that money on cases?

Maybe you're trying to build a sleeper, but you'll end up with a snoozer.

 

[jetski9010]

even if I buy the 61x cases I am still going to have to get them ported to run right with a 61x 760 setup. Then if your saying get rid of the single 44 then I would have to get a dual manifold plus find two carbs and get them setup right for this setup. I want to put most of the money for this build on the 760 setup. I already have extra 61x cylinders and a few heads around. I just want to make the bottom end I already have work for this setup.

 

[Matt_E]

Give Art a call and see what he suggests.

 

[WFO Speedracer]

There is an old saying that states "you can't make chicken salad out of chicken poop" somehow I believe it applies here.

 

[QuickMick]

If a 760 is what your looking for then just go buy a complete 760 for about 700.00. Yea Yea I know the 61X timing is suppose to hit harder on bottom but, I cant see you building a 61X bottom with a 62T top for less.

 

[jetski9010]

If a 760 is what your looking for then just go buy a complete 760 for about 700.00. Yea Yea I know the 61X timing is suppose to hit harder on bottom but, I cant see you building a 61X bottom with a 62T top for less.

a big bore 61x cylinder will hit a lot harder off the bottom then a stock 760.

 

[Matt_E]

Question is, will it do so on 650 cases.

 

[snowxr]

Exactly. you're building a top end that could rip, and choking it with the lower end/intake.

 

[jetski9010]

well I am going to try to get a hold of art tomorrow to ask him. I have a 550 motor there right now being built up and also trying to send my 96 superjet motor there to get stoked and bb.