- Location
- Costa Mesa CA
I'm sure the engines are both great iv heard all good things about these engines. What are some things to consider when choosing between either one?
The jm 718cc or 735cc
- Thread starter Ryan Declark
- Start date
- Location
- Soddy Daisy TN
I'll let chris chime in but I'm fairly certain all is the same (same porting etc) except one uses 82 mm pistons and one uses 83. I would personally go with the 718 as that would give you more opportunity to rebuild/overbore before having to re-sleeve.
Quinc
Buy a Superjet
- Location
- California
Buy once cry once. Go with the 781. Then next season upgrade to a larger pump, season after that buy a Zeel, then dual 46 Mikunis, then a lay down exhaust. And after a few years you will be maxed out on power.
- Location
- 1 Mile High in Colorado
They're all great. You're not going to notice a mind blowing difference between the 1mm over 718 and the 84mm "max" bore in he 61x (appx 753cc) - The porting work on the cylinder and bottom end and proper jetting / pipe will be where all your power comes from, regardless of the 718 or 735 cc's. A spicy ported and piped single carb 650 can feel way more fun than a stock ass dual carb 701.
Go as small as you can to start so you have plenty of seasons to bore it out if needed. You don't wanna be counting down the number of bores left right off the bat!
Go as small as you can to start so you have plenty of seasons to bore it out if needed. You don't wanna be counting down the number of bores left right off the bat!
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- Location
- CT
for the money a new 964 isnt much more then a 781. JM motors are fantastic but id take a 964 over a ported 701 all day
bored&stroked
Urban redneck
- Location
- AZ
Its not much more if you have the money to spend sure.
OP- you want the 735. Why? Because you are a MAN.
Besides, girls like big pistons. Not tiny little pistons.
- Location
- Costa Mesa CA
So my knowledge of things is basically in the 550 and the 701 realm. Are replacement parts comparable as far as price and availability is concerned? Also I'm looking to have a lake/surf ski. Not a only flip ski.
Also do you have a link to the engine?
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- Location
- Costa Mesa CA
Is the 781 that much better then the 735?
Quinc
Buy a Superjet
- Location
- California
There is a good thread on here somewhere of Blue discussing the potential of the 781. But BK made a great point about that 964!
- Location
- Glenmoore pa
781 is a fantastic motor. I learned to flip on a 781 and it’s a great way to force good technique. A 964 will make a good bit more power but it will also be a little bit of a crutch if you want to do flat water stuff. (This is coming from the guy selling the 964s btw lol) Not sure what type of riding you are doing?
- Location
- Glenmoore pa
Sorry missed the post about you wanting a lake ski. Ya I’d stick with a JM motor for now.
- Location
- Costa Mesa CA
i was looking at prices on the tpe 964, i think im gonna stay within the JM route.
it sounds like everyone's concerns are just longevity of the larger bores. but that seems to me that its a given on almost all engines.
now its just the decision to just stick with the 718 or say screw it and go 781, cuz the girls like big bulbus pistons
- Location
- Spring Lake, MI
If you're not planning on running larger carbs i'd stick with the 718/735. The 781 has a lot of case work done to help with flow. epoxied, finger ported, etc. If you've got a big set of 46/48mm carbs to put on it the 781 would see bigger benefits.
E350
Site Supporter
- Location
- Sacramento Delta
Have you contacted Chris at @JetManiac yet?
718/735/760/785 engines are Freight trains of longevity. i have seen builds last 400 hrs plus.
what these guys are referring to is ability to move on to additional bore sizes.
the 718 will give you 4, where the 735 will give you two. For those that dont know, Wossiner is now offering a 83.5mm piston
anyway, know going in, the biggest motor killer is water ingestion. If you do everything right, do your maint, quality oil and fuels.
Your motor will enjoy a nice long life .
P
what these guys are referring to is ability to move on to additional bore sizes.
the 718 will give you 4, where the 735 will give you two. For those that dont know, Wossiner is now offering a 83.5mm piston
anyway, know going in, the biggest motor killer is water ingestion. If you do everything right, do your maint, quality oil and fuels.
Your motor will enjoy a nice long life .
P
- Location
- Costa Mesa CA
Ya. Originally we spoke about the 718 and the 735. I was more apt to pull the trigger on the 35 as the price was about 100 bucks different with my core and all.
Ya water ingestion in my industry is death with diesel engines on yatchs. I think at this point my wallet thinks it can afford to replace barrels on a 781 rather than anything other than a 701 platform.
Ya it sucks that your kinda maxed out on a 781 but I'm gonna run a lay down pipe too. The buy once cry once is making me think this is gonna be the best in-between as far as money and power are gonna go.
Super excited guys. Thanks for the input. My v3 hasn't shipped yet but once it arrives I'll begin my build thread.
781 has different sleeves and better porting to start with. Ive run a JM 781 and it had solid power even on 38s. Engine life is awesome on 700 motors. If you're not going big bore sleeves I would personally just go with the 718 for more overbores. Who knows, you could have something catastrophic happen or run into an issue while tuning and smoke a piston. Pretty nice to have an extra bore laying around if you do.
JM would have to confirm but 781cc's is the displacement of an 85.5mm bore. I believe you can order a "781" package with an 84 or 85 bore to start with (753 or 771cc's) and leave yourself room to have a few bores left in the sleeves. I'm guessing they probably can go up to 86.