760 OEM flywheel charging issues

Another story for others to have data for

Changed motors in my square nose. Went from a stock 3 lobe 760 OEM flywheel / zeel setup that was working fine. (Fully charging battery and nice running setup)

Put in my Lamey motor with a 760 OEM flywheel that was lightened and purchased from a member on here. See pictures

I bought this wheel from xh2o then I tack welded the ring gear, machined the welds for clearance and then had the wheel dynamically balanced.

After first outing I had a dead battery. For sure thought I did something wrong. Put in a known good battery from my 14’. It too went dead, at first I thought it was from my tank vent issue and all the starting I had to do to test that issue. https://www.x-h2o.com/threads/sj-dies-under-acceleration.205965/#post-2115747 So once that was fixed the battery still went dead and that was after a night on charger and passing a load test. Put in the other battery and it too didn’t last but a day.

Went through the stator resistance - ok, double checked charging voltage in driveway crudely and couldn’t detect any so I changed flywheel back to the non lightened OEM 760 wheel, since the entire electrical system was same as first motor except for the flywheel. After the change back to other wheel my charging system was restored!

Message. OEM flywheels can go bad and still look like brand new. Maybe my tack welding hurt the magnets? Doubt it. Could the elimination of the 3rd lobe and exposed plastic hurt? Don’t know but doubt it. They feel as strong with a piece of metal as the replacement wheel.

I did find one other post where a guy changed his 760 flywheel and his blaster 2 ran again.
 

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Yeh this one really got me. I’ve ran probably 20+ Kawasaki oem flywheels with all sorts of mods throughout Kawasaki years and never had a failure or even heard of one. These flywheels are almost identical. 750 to 760

My flywheel will now be a Total Loss. I surely won’t be taking out magnets since I dynamically balanced as is
 
I had this exact same issue. 760 with A20T zeel, lightened flywheel ( I have all three magnets.)

Brand new oem electronics. Killed two new batteries. Putted in a brand new OEM stator. Swapped voltage regulator. Same issue.

Swapped flywheel to stock. Problem solved.

I believe the combination of zeel and lightened flywheels cause this charging issue.

I would gues if I ran this flywheel with an msd that it would be fine.
 
I had this exact same issue. 760 with A20T zeel, lightened flywheel ( I have all three magnets.)

Brand new oem electronics. Killed two new batteries. Putted in a brand new OEM stator. Swapped voltage regulator. Same issue.

Swapped flywheel to stock. Problem solved.

I believe the combination of zeel and lightened flywheels cause this charging issue.

I would gues if I ran this flywheel with an msd that it would be fine.
Thank you for sharing. Glad I’m not only one. BTW: last summer at end of year we put that lightened wheel on another boat (stock 760) and guess what? Dead battery and it that boat has never gone dead before.
 

BrightE's

Paul
Location
Seattle, WA
I've got the same issue with my lightened FW and 760 Zeel combo. It's a shame because the Zeel with lightweight FW really has a lot of pep to it.
 
To be honest. After swapping out. I didn’t notice too much of a difference.
Yup, same here but on a 62t/61x platform. A friend of mine has a nicely modded B1, had an aluminum msd lightened charging flywheel on it but the wheel developed a crack at the taper fit. Had to pull it and put on a stock 62t wheel. Never noticed a thing in spin up time.

One thing to mention regarding the kawi 750 flywheels, there was a common problem with them where they would loosen up at the hub and the rivets. I saw one that loosesned up so much the rivets snapped and the hub was left behind on the crank. Another was bad enough it threw the timing off and was getting floppy in there. The only kawi wheels I've seen stay reliable were the 650sx wheels. The 800's I don't have any experience with. There were very few of them around here.
 

Roseand

The Weaponizer
Site Supporter
Location
Wisconsin
Any more updates on this? Pretty sure my lightened wheel isn't charging. But I'm worried about going back to stock due to commonality of ring gear spinning.
 
Isn't it possible for the tack weld to throw the magnets off?
I suppose that’s possible because of the heat. Good point.

I ran a lightened flywheel and had charging issues. Swapped back to stock and haven’t had an issue since. I I’ve an Fx1 with an sj tank and it’s a tight fit. I was able to mod a harbor freight flywheel puller to work in tighter spaces. Relatively easy to swap out flywheels now with my modded tool and cold fusion flywheel lock. If I needed to swap again it would be pretty easy.

Are you running an aftermarket lightened flywheel or stock lightened flywheel?

Why are you concerned the ring gear will break lose?
 

Roseand

The Weaponizer
Site Supporter
Location
Wisconsin
I suppose that’s possible because of the heat. Good point.

I ran a lightened flywheel and had charging issues. Swapped back to stock and haven’t had an issue since. I I’ve an Fx1 with an sj tank and it’s a tight fit. I was able to mod a harbor freight flywheel puller to work in tighter spaces. Relatively easy to swap out flywheels now with my modded tool and cold fusion flywheel lock. If I needed to swap again it would be pretty easy.

Are you running an aftermarket lightened flywheel or stock lightened flywheel?

Why are you concerned the ring gear will break lose?
Stock lightened. Ring gear coming loose is relatively common especially on higher compression setups. If you do some searching people have had them break loose on stock setups. I personally had mine spin and I'm only running 180 psi. So I'm very skeptical of a stock unwelded
 
Stock lightened. Ring gear coming loose is relatively common especially on higher compression setups. If you do some searching people have had them break loose on stock setups. I personally had mine spin and I'm only running 180 psi. So I'm very skeptical of a stock unwelded
Hmmm. From what I understand lightening a stock flywheel can make it more susceptible to spinning that gear loose.
 

WFO Speedracer

A lifetime ban is like a lifetime warranty !
Location
Alabama
I noticed on the 701 62T flywheel I replaced the ring gear on that they staked the flywheel after installing the ring gear, I had to grind down the staked areas to remove it, on the 760 flywheel I got the replacement ring gear off of it was not staked, when I put the ring gear back on I put it in the oven at 450 degrees and put the flywheel in the freezer, I put locktite sleeve retainer on the flywheel then dropped the ring gear on, then I restaked then original areas with a centerpunch.
 
I always run stock flywheels on my skis. I really haven't noticed a gain by lightening it up. Maybe for flat water freestyle but not for a surf ski
Not enough for the hassle and all. It's just something for people to say they modified and say added power. No one is progressing or being held back by a flywheel
 
I noticed on the 701 62T flywheel I replaced the ring gear on that they staked the flywheel after installing the ring gear, I had to grind down the staked areas to remove it, on the 760 flywheel I got the replacement ring gear off of it was not staked, when I put the ring gear back on I put it in the oven at 450 degrees and put the flywheel in the freezer, I put locktite sleeve retainer on the flywheel then dropped the ring gear on, then I restaked then original areas with a centerpunch.
That's is exactly what I was going to say. Green loctite and use hot and cold when putting it together.
 
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