1998 YZ400F Timing Chain Replacement

Hi, I'm going to replace the camchain on my '98 YZ400F. I got the service manual and mapped out the general procedure + required parts, and I'm a bit surprised by how exhaustive the procedure in the service manual is. I was hoping someone could offer pointers or maybe some "you-don't-need-to-do-thats" that will make the job less of a pain, quicker, etc. Here's what I gathered from the manual:

Pages in English service manual PDF:

engine 154-158

camshafts 108-114

cylinder head 115-123

cylinder/piston 124-129

balancer 137-139

kick axle 143-149

stator 150-153

Removal:

1. Engine

2. Camshafts

3. Cylinder head

4. Cylinder and piston

5. Balancer

6. Kick axle assembly

7. Stator

Required replacements:

Oil cleaner gaskets 2x 90430-10188-00 (#10), 4x 90430-08119-00 (#12)

Top-end gaskets

Balancer washers 90201-167P7-00 (#5), 90201-162H4-00 (#9)

Left crankcase gasket 5BE-15451-00-00 (#6), 90201-20276-00 (#16)

Thanks,

Zeke

The cam chain isn't mentioned in the manual until they get all the way down to the crankcase, apparently because no consideration was ever given to the idea that it might ever need to be replaced for its own sake. Just be glad it wasn't set up like the early Honda OHC twins.

The cam chain isn't mentioned in the manual until they get all the way down to the crankcase, apparently because no consideration was ever given to the idea that it might ever need to be replaced for its own sake. Just be glad it wasn't set up like the early Honda OHC twins.

did you have to split cases to do those ?

I don't precisely remember whether there was a removable/replaceable link in them or not at first. I believe the "master link" became available later on, but yes, the chain ran down the center of the engine, between the two cylinders. Without the link it was a PITA.

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