I need a little advice.My son 250 started slinging oil on the swingarm.We removed rearend and pulled the drive shaft and it looks like the teeth on the pinon gear are worn along with the seal.Do i have to replace the whole unit (650 dollars) or can i get away with just replacing the pinon gear and seal (150 dollars).The parts to rebuild the entire unit is about the same as replacing the entire thing.If i replace the pinon only will mate it up with the ring gear without any problems?The quad is still in nice shape but 650 is alot to put into a quad that we bought for 1200 a few years ago.Has anyone ever repalced the pinon without the gear,and bearings?I appperciate the help and thanks

 

I have had problems with Z250 rear ends. You need to keep an eye out for play in the axle bearings and make sure there are no holes in the diff breather (plastic consetena tubing) to allow moisture into the diff. If the pinion gear needs replacing either it has had considerable useage or has been running low on final drive oil.

In my experience, I have had to strip rear ends and replace the UV joint and also replace the prop shaft and final drive linkage. K6 models had axle bearing problems (Suzuki made good on warrenty for me) but from K7 onwards, they seem to have rectified this.

To answer you question, I haven't had to replace a pinion gear but if I did need to I would just do this along with the seals and also the driving gear.