426 Broken 4th Gear Update and Other Info.....

[daveyg]

Hey all,

I posted about a month ago about my failed 4th gear and the headache of a time that I've had with Yamaha about it. Well, after two months of being without my bike, it's suppose to be finished this week, no thanks to Yamaha. First, I had to go to an undisclosed inside source for the gear and found out some other useful info about some tranny bearings they have changed on the 426's since their inception. Also I found out that the pin in the shift shafts are coming out since they weren't peened over enough from the factor, so you should have them tack welded. It's not a hard thing to do, but if left alone it could have a field day on your motor. Also, the clutch problems that you all are having is not a mystery and Yamaha is well aware of this. Yes, they will warranty those 50 found in a particular serial number range, but I personally know of a half dozen people that have had clutch failures, so I would venture to say there are many more than 50 out of 5000 failing. Nonetheless, I immediately upgraded to a Hinson when I heard about the first two failures. I recommend it highly.

After replacing 3rd and 4th pinion gears (had to replace both since I don't trust the old 3rd gear any longer) I hope I have no other problems. After all of my heartache with this bike, I can't wait for Honda to put out a kick ass 426 beater. I'll be the first in line!

Daveyg in CO.

[Hick]

daveyg,

How about some info or contacts on the shift shaft fix?

I am worried about my YZ because:

1) Clutch makes noise at idle

2) Often difficult to shift from 2nd to 3rd gear.

When you upgraded to a Hinson did you replace basket only or complete clutch?

What is the best way to visually determine if my clutch basket should be round filed?

[daveyg]

Hick,

As for the shift shaft pin problem, I heard it from an inside Yamaha mechanic. The pin has a tendency to come loose and can cause severe damage to your motor. Have the pin tack welded on the backside so it can't come loose. It's a fix that can be done pretty easy from the clutch side of the motor. A qualified mechanic will know what to do.

Get the Hinson, new steel plates, fiber plates, and a new clutch boss. I replaced mine right after break in, so I didn't have to replace all of that stuff, but if your clutch has been used substantially, replace it all. If your clutch is making noise, do it immediately. Have a mechanic do the basket replacement for you since the rivets have to be ground off the old basket to use the existing drive gear on the back of the basket. The rivets can be drilled too, but just be careful not to damage the backing plate or springs.

As for your stock basket, I wouldn't know what to look for to see if it's a defective one or not, but I wouldn't take the chance with all the failures I've heard of.

Good luck with it.

Daveyg