98 YZ125 Questions & should I get 2002?

[skhasky]

Hi All!

A few questions....

I have a 98 YZ-125 in perfect condition. 1/2 MX (intermediate) and half trail riding. I run Yamalube 2-R and premium unleaded 32:1.

Here's my laundry list....

1. At my altitude - 5,280' I run a 310 Main (stock is 350), S-8 nozzle (stock is S-9), 70 needle (stock is 69) 3rd clip, and 35 pilot (stock is 50) - it runs awesome and has a tan plug (BR8EVX). Great low, mid, and high. But it 'seems' aweful lean by the numbers. Does anyone else run at this altitude, and what jetting do you use?
BTW - I would run race gas, but at this altitude it seems to make no difference.

2. When I got this bike, the dealer was going out of business so I got tons of spares at 50-75% off. Extra bearings, cables, cylinders, heads, jets, seals, even a spare crank! About 50 pounds worth of spares! Well, I see the new bikes and reviews out, but I love this one and I have enough parts to last 2 lifetimes. Should I trade up or is my old 98 still a competative ride.

3. Bottom-end. I don't know what voodoo is going on in my engine, but I am getting 20+ hours out of the topend and have never needed to split the cases. I tear it down every ten hours anyway - but usually the ring gap is perfect, the piston measures perfect, and there is no up/down play in the rod - just a teeny bit of normal side play. Anyone else having this 'luck'?

4. Finally (and thanks for the patience/input). I lose about 20-30 cc's of tranny oil every time i ride. Is this ok? My seals don't seem to be leaking, and no crud on the plug. I have a hunch that when I use synthectic 30wt I 'use' more than when I use standard 30wt, but it may just be my imagination. Does everyone else have a 'vanishing' oil issue?? Not much, mind you - just a little each time.

Any other comments on the 98 vs other yz-125's would be greatly appreciated. Thanks for all the assistance!

Steve

 

[marcusgunby]

I loved the 98 engine on the one i rode-my all time favorite std engine.Loosing a tiny amount of oil may be just from it blowing it out the overflow.If it runs well and is holding up well why spend the extra?

 

[yz_387]

I had a 98 yz 125 and kept it for 3 years and I had the same kind of "luck" as you describe. The engine seemed bulletproof, but I rebuilt it fairly often anyway. In fact I sold it to a friend, and to this day it is still on the original crank, and the cases have never even been split. As far as the tranny oil, I ran 80w spectro, and lost oil every ride out of the overflow. A friend of mine had the same bike, and used Honda tranny oil, he lost oil on every ride too. I have no explanation as to why that happens, but at least you know you are not the only one experienceing this. Of all of the bikes that I have owned and sold, that is the only one I still wish I had.