(repete from old thread)
IMHO .. the YZ gear set isn't a wide enough ratio for a 4 wheeler .. to get some low speed grunt you sacrifice top speed & if you want a decent top speed the bike is scooting right along at idle in 1st .. lotsa clutching on trails .. we change sprockets & chain going from trails to dunes .. the Blaster 6sd is perfect with it's super low 1st
I don't have the ratios for newer YZ'S. I used WR gears cuz 1st is a bit lower than the Blaster 2nd and 5th is a bit higher than Blaster 6th. WR 5th is like overdrive. The YZ is taller in 1st than the Blaster 2nd and lower in 5th than the Blaster 6th. To me the WR gear set seemed better suited for a quad. Guess it depends on what you want. The 92 is a good motor. With these swaps the pipe is always the issue. Anyway, sumthin to think about with the WR/YZ swap.
Here's sum numbers to give you an idea of the difference between the Blaster, YZ and WR gearboxs.
Gear Ratios
---- Blaster --------- 89 WR250 -------- 90 YZ250 -------- Tri-Z
1st 34/11 (3.091) -- 32/14 (2.285) -- 31/15 (2.067) -- 30/14 (2.142)
2nd 31/14 (2.214) -- 29/17 (1.706) -- 29/17 (1.706) -- 28/16 (1.750)
3rd 25/15 (1.667) -- 24/18 (1.333) -- 22/16 (1.375) -- 26/18 (1.555)
4th 20/16 (1.250) -- 21/20 (1.050) -- 22/19 (1.158) -- 24/20 (1.200)
5th 19/18 (1.056) -- 21/25 (0.840) -- 23/23 (1.000) -- 22/22 (1.000)
6th 19/21 (0.905) ------ N/A ----------- N/A ------------- NA ------