Suzuki 2 Strokes

I am in the process of doing a crank rebuild on my T500 , new seals etc.
As the crank is pressed apart, is it worthwhile filling the large balance holes with aluminium plugs to increase the crankcase compression ?
Anyone done this? Were the results good, bad or just not worth the effort?
It’s always good to get all the info, and others opinions before doing anything drastic.

Andrew Holley
Dubbo
Australia

Andrew, Those balance holes are there for a purpose BALANCE. The extra compression you would get would be miniscule.

I have lightened cranks by drilling holes and filling them with a lightweight composite material but you need to know what you are doing to drill in the correct areas and still need the know how and tools to re-balance afterwards. Just filling the few balance spots isn't going to do much but if you found a machinist that could do it correctly it would make a small difference. You could also find someone that can lighten the crank like I explained but thats more for high revving race engines the engines I built like that would be useless for on road use.

Hi Andrew,

Back in the day I had a T500 race engine with a lightened crank, with full circle "stuffers" to take up the space of the reduced diameter crank. However the need to do this, especially with fast burning modern fuels, is a lively area of debate. I now have a race engine with a lightened crank with no stuffers and it performs just as well as the old one. I don't think you need to fill those holes, any difference would probably be un-detectable other than on a dyno.

Cheers Geoff

I agree many claim the less case volume the better but many of my watercross sleds run the polaris liberty twins which are case reed and when I'm done porting the case theres quite a bit extra volume. I made up for it on one engine by epoxying low flow areas bringing the volume back to 5cc's smaller than stock. It did make a difference but the other engines I have still run strong without it.