Help: Case crossover question

[Berkyboy]

We're having trouble determining what year 2003 250/300 GG cases will work for.

Will they work for: 2002, 2001, 2000 ???

[gasgasman]

In '05 they went to a more compact case.
The counterbalancer (real) bearing mounts and passages were eliminated.

The '98-'04 were the same, with some differences in the water pump cover gaskets.

[GMP]

Steve,

They are not the same. The issue is the crank bearing change. In '01 or '02 (I think '02 but not sure which year off hand) they went to an ignition side roller and smaller primary side bearing, so the case bearing bores are different. Not sure if the cranks (journal dia.) are different, we would have to dig back in the older parts book (unfortunately not on-line). I know the '00 is different for sure, as I had and '00 and have an '03. You could always use the cases but you would have to use the matching crank IF it is different. So, from what I know the '03 cases are good for '02 through '04, and probably through '06.

[rockyroad]

Fairly sure my '01 250 had never been opened by previous owner, had/has roller bearing on ignition side.

[GMP]

Then its '01 that has the changes in bearings, because the sizes are different.

[PEB]

So are we certain that 03 cases will work for an 02 crank and other internals? I suppose I will still have to inspect the new cases relative to the old ones, to be certain.

Paul B

[Loosenut]

It was my understanding that they changed the crank bearings for '01. But GasGas may have done the mix and match in '01. The '05 cases are completely different from the previous year model as someone already pointed out.

Loosenut
aka Baxter

[Berkyboy]

I checked on the critical internal part numbers and the last change was in 2002.

I suspect that the engine case serial number (which is on the left case) changes each year, but thats just a theory.

Does anyone know if the 2004 or newer engine will fit in a 2003 or older frame?