If I understand physics correctly a lightened flywheel will help an engine "spool up". My question is. Is there a lightened flywheel / rotor ?
thanks for any info
Gordon

You can machine the stock flywheel and reduce the mass but you need to be careful as there is a risk of the thing coming apart on you.
Another way is to fit powers park ignition system with one of the light flywheels they produce.

Glenn

Gizmos was working on spacers to use the TK small flywheel and coil for a zen bottom at one time.
Also the cy flywheel is a little lighter, light enough to make a difference but you have to space out the source coil notch the starter and grind off the paws if you want to use the easy start. The cy flywheel does not overhang on the crank like the Zen.






I'm also going to try using the CR crank and the CY fly wheel but I would have to use CR bottom and modify it with a front plate and spacers for coil and starter.



The only thing I don't like is the unsupported space between the bearing and the flywheel. That's why I'm going to a custom CR bottom end.




Look at the difference in space between support. 12.00 crank with no steps and 45.00 bottom complete with 4 bearings to play with. www.gizmomotors.com/index.php/...rankcase-detail

I don't see where anyone has pointed out where to take the metal off and how much.

I know Tiger king has a smaller diameter rotor (flywheel) which is lighter, Gizmomotors also sells a lightened TK flywheel 94 grams. All that needs to be done is make an adapter for the TK source coil. There have been many discussions about taking weight of a stock Zenoah that is not what I want to do.

We run a CR crank in a CR case and the amount of crank sticking out will probably not be enough for any marine flywheel. We have a custom made flywheel with power spark ign. Even if the flywheel will seat correctly, the OD of it will not be small enough for mounts. The whole front of the case will need to be cut away to fit in a boat. Nothing will be left.

Gordon
I fitted the QD case with the TK small flywheel but nothing else will work (that I have on hand ) (Zen / MK) not sure about TK - maybe MK SX case will work. Another issue was the crank - I had to use TK crank to get proper spacing with crank taper on front
- just me though sure others have fitted it before ...

Here is QD (first fit) - will go into LZ as well - -- should have this ready soon - tweaking it for next week

RD

I think it's safer to use a lighter fly wheel. I don't know that you can remove enough material safely from a Zen to be as a CY in weight. The third pic shows how close the CR crank with the CY fly wheel comes to fit in a pum case, less than an 1/8".

This post is wrong about what I said about the third picture and the crank crank. Flywheel is on the wrong end.
Also want to point out that it looks like I would have to shave off about 1/8" between the CY flywheel and CR case. Won't know for sure till I get it.

I am new to gas engine mods but why not just drill some holes in the Zen flywheel to lighten it up instead of reducing diameter?

Tim

Some are successful at drilling and thinning them out but some fall apart at speeds and the damage it causes is scary ugly. You don't want a very light fly wheel if your a heat racer cause the weight momentum helps through out the turns.