quadzilla

The big zillas were great MONSTERS of stock power. However, they suffered from a BIG issue over time, and lets face it, these are NOT new machines any longer.

The issue is with the balance of the crank and porosity of the aluminum cases. Over time the incorrectly balanced crank rattles and wears out bearings. If not caught right away and fixed, then the bearings start to rattle in the cases and become loose.

Arlen of LED (formerly of LRD) and Charlie Brown of NW Sleeve here in Portland came up with a great idea back in the middle 90's. They would over bore the crank bearing bosses round again and install a case hardened steel sleeve. This would fix the immediate problem of leaking crank seals and lean run conditions, but ultimately you have to buy a Crank Works fully balanced crank to cure it.

The costs of these repairs out weigh the probability of ownership. You will spend more keeping the engine alive then you paid for the bike (3x) over.
 
thanks dunes, i got to thinking about how theyre hard to come by, and its probly for that reason. i built a 88 CR250 a few years back and that same issue; granted i was running a 300 stroker motor burnin nitro for hill climbing. anyways, i ended up wallowing out the crank bearing seats(bosses) and had to by a new bottom end. which is when i decided to tone it down a bit so i could sell it:P
 
A properly built banshee will out run ANYTHING. Except for an even better built banshee haha...Its the best feeling when your out riding and a punk kids rolls up on daddies built 450 and you straight equalize him in front of his friends...