500 Two-Stroke Tech

Hi,

Anyone tried lighter crank flywheels or stator ?
Would it make the engine more difficult to manage on the throttle ? The engine just seems so heavy for a small 500 2 stroke and I wondered if there was somewhere that some weight could be lost - perhaps all components are just that little bit heavier than in a modern engine and it all just adds up to it being heavier than expected ? Where does an RG500 save its engine weight compared to the RD500 ?

Thanks.

Cheers
Paul

Hi Paul, we machined the fly wheel down I think was about 3 ounces in weight. It's on the bike running haven't ridden it yet.
First saw pictures of this done in Japan.
Cheers Ron.

I used to race a 350YPVS. It had a lightened flywheel like that. It certainly was one of the fastest on the grid. No down side as far as I could tell.

I have used a Motoplat ignition on a 350LC and that had a small/minimal flywheel, which was tiny when compared to stock. Ran great, but no charging capability...
With the RD500 crank geometry and their relatively high polar inertia, I would suggest that the stock flywheel is almost superfluous, apart from ignition/charging purposes. Got to be wary of harmonics/dynamics though....
Re. the overall high engine mass, losing the cast iron liners, going to separate heads, plastic cases (like LH TZR etc), maybe electric water pump, smaller clutch, etc, could result in 15+ lbs reduction in weight.....

Thanks for the info everyone.

It sounds like making the engine lighter could be a really big project all on its own.

Cheers
Paul

The RZ's clutch is massive. I have heard it compared to the TZ750 clutch and the RZ Tranny is more robust than the RG as witnessed by necessary upgrades needed to improve longevity on the RG. 2 areas that are hard to reduce weight. I don't know about the cylinders. Regardless of liners which the RG has the same issue, the next generation unlined 2 stroke barrels had far less extra casting in comparison. More Port area and less wall thickness and larger cooling passages. Example TZR 3xv VS RZ500

YPVS, arguably the best of the exhaust tuning designs, is probably heavier than other designs as well.

The first and easiest measure to reduce engine weight is to remove the balancer crank and these anti- lash gears on the primary drive gears ( not sure if this is the right term). I run 3 RD500 engines without balancer crank and have no issues with vibration.

wolfgangh wrote: ↑Sat Jul 18, 2020 5:00 pm The first and easiest measure to reduce engine weight is to remove the balancer crank and these anti- lash gears on the primary drive gears ( not sure if this is the right term). I run 3 RD500 engines without balancer crank and have no issues with vibration.

I always wondered about the balance shaft, None of my bikes run the anti-lash gears, But I always wanted to leave out the shaft, It was the thoughts of stripping it back down if it went to shit that put me off.

Any difference in vibration