gearing/transmission on 01 520 mxc

[bkej]

I just purchased a used 01 520 mxc from a local dealer and it has a 13 tooth front sprocket on it, but it still seems very tall geared in 1st. Does anyone have any suggestions? Will a 12 tooth front sprocket do any major chain damage? I'm hoping I didn't make a mistake, they also had an 02 520 exc but it was another 1k in price.

[ACH]

Is the rear still a 48? Even with 13/48 it is still a bit tall but you can get a 52 and possibly bigger. I'm using the 13/48 for now in pretty tight singletrack and it works. When I need new sprockets I'm going to 13/50.

In the tight stuff you'll like the close ratio trans.

[MotoChris521]

I just went 13/50 on my '05 525 mxc.Much nicer at crawling speed.still hauls a$$ in 6th.

[Dave Hopkins]

The MXC gear box is a bit problematic as its geared quite tall internally, it is intended for Baha!

Rule of thumb that applies to any dirt bike, less than 13 in front, or more than about 52-53 in rear and they become a maintence nightmare.

[ACH]

The MXC gear box is a bit problematic as its geared quite tall internally. . .

Just curious why you say the mxc gearbox is problematic? 1st gear is taller than the exc, yes, but they're the same at 5th gear. 6th in the exc is taller than the mxc.

[BarKerKTM]

I have got a 2000 520 EXC and it is tall in first, here in OZ the EXC's were a factory 14/50 but most recommend 13/52. At 14/50 I could get over 150Km/Hr but I would have to ride the clutch in tight forests.

I have gone to a 13/50 and for me now it is almost perfect.

[Chas_M]

Just curious why you say the mxc gearbox is problematic? 1st gear is taller than the exc, yes, but they're the same at 5th gear. 6th in the exc is taller than the mxc.

The only gear that the MXC and EXC have in common is 4th gear, with all other gears being much more tightly spaced on the MXC both above and below 4th gear.

[ACH]

Yes of course that's right. My mistake.

[Dave Hopkins]

EXC has nothing to do with an MXC, to get the same 1st gear you have (21.5 to 1) an MXC would need 12x56! That 12 will wear out chains, sprockets and the plastic pad on the swing arm very rapidly, the 56 will have the chain dipped into the mud in every rut, makes for a high maintence nightmare.