Freestyle Looking for 62t 760 freestyle specifics 64x Decking Porting

Quinc

Buy a Superjet
Location
California
One benefit to re sleeving the 61x or any cylinder is if the custom sleeves ports are shaped/configured differently/better then oem?
 

Half flip95

Formerly pondracer95
"This sport is completely subjective when it comes to engine performance. The only two meaningful aspects of freestyle propulsion is response and thrust. I have not found, in the past 20 years, another jet ski rider timing throttle response or measuring thrust. Its all based on personal opinion."

you could line them up next to each other on the shore, set up a buoy a 50 yards away, then leave at the same time, and see who gets there first.

"There are only a handful of us that have done this"
yes, those cylinders have been in existence for 20 years, but just now are people beginning to experiment with them. you are like a pioneer in engine building.


"I was into mine way less $ than that"

"I bought a used head with really crappy domes off ebay for like $60 shipped.
It will give others the chance to pick up 760 cylinders for $60 like I did
Machine work $100 (again I had a buddy do it for a couple cases of beer)
Gaskets $100"

"My actual cost was only about $175 but I had a lot of parts to trade/ ect."

Well that's actually 60 + 60 + 100 +100 = 320

Your math makes the whole story suspect.


You have a motor that you are happy with. Cool, but there is no need to go on the internet and exaggerate facts to make it sound like something its not.

you did not build the fastest bigbore ever built for 175.00
 

Quinc

Buy a Superjet
Location
California
He isn't arguing. He is sharing that instead of following the herd and dumping a ton of cash on a 61x BB, he built a very similar engine for significantly less money. Possibly better with the 64x cylinders being stronger then 61x cylinders. I am sure everyone including Lamar would love to hear any sound arguments on if he would have been better off with a 61x.

So far only thing I can come up with is having custom made sleeves. But, you can also fill the outside of a barn with what i don't know.
 
@Quinc The carbs are powder coated in a Crome powder I was trying. They turned out ok but I don't think I will ever powder coat carbs again you really have to pay attention to all the holes and ports, And have every size silicon plug. They may not be that shiny now but they still look good and three trips to the ocean hasn't corroded them yet.

@lamar311 I I'm running duel pickups one to each carb.

@ other people 100 hours is only 2 hours a day 5 days a week. 10 weeks of winter. Here winter is way longer then 10 weeks soooo.... It's not that hard to put in 100 hours in a hobby that you enjoy. I guess I like wrenching as much as I like riding in the winter. If it were summer well let's line them up. And in no way do I think I am the authority on motor building. Never said I was. This whole process was to see if I could learn something. I have. And I would do it again. Unless any one wants to give me a new tpe964. Lol
 

Half flip95

Formerly pondracer95
Quinc - I think you're having a problem with reading comprehension. Go back and read all of my posts once more. Did I mention 61x anywhere? All I did was call bs on three ridiculous claims. by lamar 1.fastest bigbore ever 2. 175.00 3.There are only a handful of us that have done this

sasquach - you did your deal and ended up with a product you are happy with. you acknowledge the fact that this endeavor took a lot of time and effort to get to the final result. To you 100 hours might not be much of an investment, but the casual browser that may be considering this ought to know the real cost to get this thing working right before buying a bunch of odds and ends in hope of putting together that 500.00 hombrew power pusher


"So far only thing I can come up with is having custom made sleeves. But, you can also fill the outside of a barn with what i don't know."
Quinc - im not going to comment on this, the reason i take the position that i do on this topic is because i have been stuck in engine builds that weren't as cheap, easy, or mindblowing as advertised. if posters on the internet had given more realistic expectations i might have went with something more conventional
 
Location
dfw
The biggest complaint of a 760 cylinder is that it is not responsive enough. By lowering the whole cyl you gain swept volume, increase the blowdown period, and lower the tuned rpm. The positive effect is better response and a harder hitting pipe. The negative effect is less rpm and HP potential. Nothing magical, just basic two-stroke tuning. Mods like this are not pushed by shops because there is not enough money in it. They really need to sell a $1200 mod in order to keep the doors open.
 

Quinc

Buy a Superjet
Location
California
the reason i take the position that i do on this topic is because i have been stuck in engine builds that weren't as cheap, easy, or mindblowing as advertised. if posters on the internet had given more realistic expectations i might have went with something more conventional

You have done this same build and the results where not great? Can you give anymore info/specs about it?
 
"My actual cost was only about $175 but I had a lot of parts to trade/ ect."

Well that's actually 60 + 60 + 100 +100 = 320

Your math makes the whole story suspect.


You have a motor that you are happy with. Cool, but there is no need to go on the internet and exaggerate facts to make it sound like something its not.

you did not build the fastest bigbore ever built for 175.00[/QUOTE]

Allow me to retort...

1. I had the cylinder & pistons that I built. I did indeed buy a second 760 cyinder for $60 however that was for a future build. I ended up trading it for the 62t cases that I used as my motor was an odd 61 x case with 64x cylinder...so I guess you could add that to the build cost. I wasn't including my traded parts in the cost that I quoted in the $175.

2. I spent $100 in gaskets and 1211. Also I bought the head for $60 shipped. I than bought a $15 case of beer to give to my buddy that did all of the machine work. Everything else I traded for. So build cost.

$100 gaskets + $60 head + $15 beer = $175 ($60 more if you included the purchased cylinder that I traded for the cases....however I 'd have to tally all the traded parts I used if this is included)

I did explain that I saved money due to having parts and a friend to do the machine work. Also, I estimated it was about a $500 build if you had to buy the carbs, cases, and used head.

3. I would and never have claimed this to be the fastest big bore. I said I'd put it next to any BB out there, and that for the $ this is a fantastic motor. I could careless about top end. All I wanted out of this motor was backflip capability. I have it and it is comparable in power to the other BB I have ridden locally.
4. There is no exaggeration as far as I am concerned, and I am no innovator. Just riding the coat tails of others and it worked. I had very little time and $ invested in this motor and the results were very very lucrative.
5. Sorry you got stuck in a build that cost you way more than you expected and yielded the results you got. I had the same experience with a 62t set up so I can get the irritation. I felt the same way going into this build and had that attitude that it would be a subtle difference. The only reason I did the build was due to the cost I knew I'd get into with the trades I was able to make and a machinist buddy. So my expectations were low but were FAR exceeded.

Best of luck with you next build whatever it is. If you are willing to spend the big $$$ and go DASA or TPE than don't go this route. Use it as a back up motor for a back up ski. However if you are like me and would rather sink the cash into your house than your toy ...go this route and know it will never be as powerful as a powervalve motor....but smile that you got way less $$$ in it and it still performs pretty damn good.
 
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Best of luck with your next build whatever it is. If you are willing to spend the big $$$ and go DASA or TPE then don't go this route. Use it as a back up motor for a back up ski. However if you are like me and would rather sink the cash into your house than your toy ...go this route and know it will never be as powerful as a powervalve motor....but smile that you got way less $$$ in it and it still performs pretty damn good.

Well said.
 
Also, it should be noted my jetting was for a single fuel line in vs. a separate line to each carb. I have now switched to dual pick ups and will report back on tuning once I have it.
 

Half flip95

Formerly pondracer95
Here are the beer expenses you listed in post #148:
1)Decking the cases is super easy for any machinists to do. I had a local guy do it for a case of beer (granted he is a buddy).
2)Machine work $100 (again I had a buddy do it for a couple cases of beer)
3)All porting was done by another buddy using the sport port template. Again on the cheap (Beer)

In post #170 your "retort", you accounted for 15.00 worth of beer.

So what was it? one case, a couple of cases, + another case for porting?

"There is no exaggeration as far as I am concerned"

The point is not how much beer it actually cost you. the point is that it is impossible for all these statements to be congruently true. At least one part of your story is fabricated or exaggerated.


"I would put it next to any resleeved big bore and can gaurantee it pulls as hard"

To anyone actually reading the words on the screen, that says that you are on par with any re-sleeved bigbore.
To my knowledge "any re-sleeved bigbore" includes the fastest and best accelerating re-sleeved bigbores ever built... and you claim to be on par with them.

"I would and never have claimed this to be the fastest big bore."

Then you put together this abomination of a sentence and it throws my whole train of thought for a loop. Without a doubt, you claimed to have a motor that is on par with any re-sleeved bigbore. But I have theory as to why you might be very clearly typing something and then denying it.

Is English your first language? I speak Spanish very poorly and there are many times where I fail to recognize the subtleties of the language. I often make incorrect statements, but native speakers tend to let it slide because I am still learning the language. A language barrier would certainly explain why the details of your transactions are so convoluted.

If English is your first language, there is a possibility that you may just be ignorant. If this is the case then the above statement still applies.

If English is your first language and you are literate, then you are lying and denying.
 
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Quinc

Buy a Superjet
Location
California
58314668.jpg
 
wow... @pondracer do you really not have anything better to do with your time??? Let it go...the point is these 760 builds are turning out great and putting out a lot of power for the money. I myself have decided to go with an HPE 809 stroker version which is still a bargain but was seriously considering this route as well. Even if he is in the engine $500 that is still CHEAP to be making a ton of power...LET IT GO
 
*Sigh* I am not going to get into a mud slinging match...nor do I care to waste any more of my time going back through the 176 posts to try and make my point or pick apart my own posts. Pondracer ..perhaps this will make you happy.

In summary:
The motor runs ok, it pulls like any other motor out there. I did however spend a fortune and wasted a ton of my time on it. You should all buy big bore sleeved 61x cylinders or a power valve if you want your ski to run well. Don't even bother with the 64x cylinders...they are junk, crap, terrible, and will cost you more in the long run than doing paying a professional to set you up right. Go spend your money with a professional builder and avoid modifying 760 motors at all cost.

However, PM me if you'd like some info on what I attempted to do.

That better?
 
Location
usa
The biggest complaint of a 760 cylinder is that it is not responsive enough. By lowering the whole cyl you gain swept volume, increase the blowdown period, and lower the tuned rpm. The positive effect is better response and a harder hitting pipe. The negative effect is less rpm and HP potential. Nothing magical, just basic two-stroke tuning. Mods like this are not pushed by shops because there is not enough money in it. They really need to sell a $1200 mod in order to keep the doors open.
just to help clarify... this is incorrect
moving the cylinder up or down won't change blowdown
you would have to port either the exhaust height or the transfer height to change the the spread between the two ports in order to change blowdown
 

waxhead

wannabe backflipper
Location
gold coast
just to help clarify... this is incorrect
moving the cylinder up or down won't change blowdown
you would have to port either the exhaust height or the transfer height to change the the spread between the two ports in order to change blowdown
actually it does change blowdown, I understand that the distance does not change between the two ports but the crank pin is in a different postion. The piston speed is not linear and it is faster or slower depending on the crankshaft postion.
This changes blowdown
 

Quinc

Buy a Superjet
Location
California
actually it does change blowdown, I understand that the distance does not change between the two ports but the crank pin is in a different postion. The piston speed is not linear and it is faster or slower depending on the crankshaft postion.
This changes blowdown


Wax, I am sure you have built one of these. How do you think it compares?
 

waxhead

wannabe backflipper
Location
gold coast
Its awesome, the only thing better than a 64x cylinder is a 62t cylinder.
I avoid running 61x cylinders on my own builds because it so much work to get them to run as hard as a 62t.
The 62t has a lower exhaust port than the 64x and so does not have the same amout of blowdown. This limits its top end power but it gives it good hit. The reality is if you prop your ski right its going to have hit anyway.
 
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