Continuing with the 2005 tear down...
As mentioned before the 2005 FD was already partially disassembled before this, so the 2WD engagement coupler is already off of the 2WD splined hub in this pic.
You just pull the 2WD fork and the coupler moves to the end of the splined hub and slips off.
A couple of things to note here.
First there was a number written inside the case, at the 12 o'clock position.
I'm not sure if that is a "12" or a "21." Any guesses as to what it means? I have no idea.
It's funny that the number lasted for who knows how long inside the case with oil, but when wiped with a rag it came right off.
Next Difference #4
between 2005 and 2010.
There are two "pins" that sit in the holes in the ends of the forks.
They are technically removable on the 2010, but are a pressed fit, they don't come out easily.
On the 2005 they are a slip fit and fall right out when the coupler is removed.
The pins are a different shape, so not sure of the pins and slots are interchangeable.
I'll try to remember to look next time I'm working on it.
Anyway, the cotter pin located on the 2WD fork between the pivot and the splined hub needs to come out.
Get the needle nose pliers and slip it out...
With the pin out you slide the pivot out of the top of the case and the 2WD fork comes right out.
This pic shows the pivot and fork assembled, laying on top of the case.
If you look at the tip of the uppermost fork arm, there is a small tab, that sticks out longer than the other arm.
This tab engages the ball detente sticking into the case at 11 o'clock, which holds the bike in 2WD
Next a split ring holds the 2WD splined hub in the bearing.
The splined hub is inserted into the case from the outside and the ring keeps everything together.
Here is the view from outside the case.
Yes that bearing will be replaced.
I have bearings with rubber seals, so when I install the new bearing I will pull the seal exposed to the oil and leave the seal on the outside to help protect the bearing better.
The factory solution is that the o-ring on the 2WD yoke should
seal that area but as you can see, that is less than ideal.
between 2005 and 2010, the 2005 uses a split ring and the 2010 uses snap ring style circlip.
I found the split ring to be a bit harder to get off.
I used a pry bar and flat head screw driver to spread it then got a probe under the ring, then was able to pry it up, but bent the ring a little.
The shaft diameters, groove depth and width are the same, so I ordered some new snap rings and will replace both with new.
I'm jumping ahead a little in the next pic, but here is the 2005 and 2010 clips side by side.
I prefer snap rings with holes, so much easier to remove and install.
As you can see, the split ring one is bent.
Next set the case on your vise, so that the outer edge of the case is supported but the flange of the splined hub is free to drop out.
Put a chunk of wood on the splined hub and tap with a hammer.
The hub should drop out of the bearing.
With the 2WD splined hub out, you can see the bearing in the outer case.
Take a punch and hammer and tap around the bearing at 3, 6, 9 and 12 o'clock from the outside of the case.
Ideally you want to catch the outer race, but the seal is in the way so space is limited.
I'm sure there is some sort of bearing puller that would pull it out by the outer race but I have no such set-up.
I was hitting the inner race but this is a light press fit so my bearing dropped out easily after two taps.
This bearing was in good shape (note this is not the bearing pictured above) so I may reuse it.
Then from the outside of the case, punch out the seal.
The spring popped out but this seal was in pretty good shape, and it wasn't leaking so could likely be reused, but I found a viton seal at a reasonable price so both cases will get new seals.
With the case cover empty of parts, it gets a degreasing and I move on to the pinion gear.
The pinion gear takes ALL of the force of the engine and rides on two bearings, the needle bearing at the tip and the double row roller bearing (F A G 3304B.TVH) at the spline shaft.
I will repeat that for emphasis...every horsey your engine can muster, after being multiplied by the gearbox is putting force on these two bearings.
I recommend replacing BOTH of these bearings if the pinion is trashed.
If you have opened the case just to replace leaking seals and the FD is in otherwise good mechanical shape, you can leave these alone.
You can probably pull the double roller bearing intact with a bearing separator/puller, but if the pinion is trashed, you are likely trashing the bearing as well, so it doesn't matter how you remove it. Or even IF you remove it.
I only tapped the pinion out because I will keep the ring and pinion for comparison/reference/decoration and it stores easier without the bearing on it.
The roller bearing was pretty loose, as you can see the inner bearing race is still up against the teeth, after tapping the pinion out.
As for the needle bearing, my last one took a lot of force and heat to remove.
I don't know if the older ones were easier to remove, but as I said above, I believe if the pinion is trashed, the bearings should be replaced, so I'll be replacing mine.
Set the 2WD splined hub in the vice so just the edges of the flange are supported and the bearing can drop out.
Then take your drive shaft and tap the bearing out.
Then when the bearing comes out, but is stuck on the shaft, set the bearing on the vice and tap the shaft out.
Next up, let's compare the breakage of the ring gears.
Below the 2010 gear is in the foreground and the 2005 is in the background.
I broke the 2010 on Bloody Skillet, a tough and challenging ATV/UTV trail that I later found out we probably shouldn't have been on.
I rode down the mountain a little ways on the damaged teeth before it was towed out.
The 2005 failed in the Pines, not even revving or stressing things.
I stopped almost immediately and ReCycled towed me out, after covering the FD spines with the dust cover so the pusher could freewheel.
The 2005 lost 3 full teeth, right down to the base of the cuts.
The 2010 lost 1 tooth and chipped two others, about 1.5-1.75 teeth in total.
This would seem to indicate that the ring gears have definitely gotten better.
That's it for the 2005 FD, I'll be tackling the 2010 disassembly next.