400ex cam cover/head cover bolts

[Knowpig]

I have a sheet that says 8 lbs-ft for the head cover bolts.
Are all the 8mm head bolts and the one 12mm head bolt all 8 lbs-ft, or are they different?
Please help!!!!!!!!!!!!!

Also, what is the torque spec on both of the side covers.

Thanks again!

[Doibugu2]

Just the large bolt is 8lbs. The other bolts are just snug. They break very easy so do not over tighten them.

Not sure about the covers.

[JOEX]

Originally posted by Knowpig
I have a sheet that says 9 lbs-ft for the head cover bolts.
Are all the 8mm head bolts and the one 12mm head bolt all 9 lbs-ft, or are they different?
Please help!!!!!!!!!!!!!

Also, what is the torque spec on both of the side covers.

Thanks again!
The manual is a bit misleading for the home mechanic. The listed bolt size isn't the same size as the head of the bolt.

On the 400ex valve cover there is only one '8mm' bolt and it should be torqued to 17 ft. lbs. The rest of the bolts are just 'snugged up' in an alternating pattern, no torque specs are given.

[Knowpig]

That's what I needed.
Thanks!

[GPracer2500]

Originally posted by JOEX
....no torque specs are given.

The manual is kinda misleading. There IS a torque spec for the 12 6mm flange bolts.

In the OEM service manual, in the General Information section there are torque specs for all the bolts. There are "standard" torque specs that provide a spec based on the size of the bolt rather than it's location on the machine. Following that section there are torque specs for specific bolts. If a bolt/fastener isn't covered specifically then it falls under the "standard" specs:

6mm flange bolt (8mm head, small flange) = 6.5 ft-lbs
6mm flange bolt (8mm head, large flange) = 9 ft-lbs

I forget which one of those are the valve cover bolts. I think they are small flange. And there's a bunch more--covering every fastener found on the machine.

In the cylinder head section of the manual they don't mention the 12 6mm bolts, only the single 8mm bolt. When a fastener's torque spec isn't specifically mentioned then you default to the "standard" torque specs for that size fastener. Since the head on the 6mm bolts are 8mm, when folks see the 17 ft-lbs torque spec for the 8mm bolt they assume they're talking about the 12 6mm bolts. And walla! You've got the most frequently over-torqued bolts on the 400EX.

[Knowpig]

Originally posted by GPracer2500
The manual is kinda misleading. There IS a torque spec for the 12 6mm flange bolts.

In the OEM service manual, in the General Information section there are torque specs for all the bolts. There are "standard" torque specs that provide a spec based on the size of the bolt rather than it's location on the machine. Following that section there are torque specs for specific bolts. If a bolt/fastener isn't covered specifically then it falls under the "standard" specs:

6mm flange bolt (8mm head, small flange) = 6.5 ft-lbs
6mm flange bolt (8mm head, large flange) = 9 ft-lbs

I forget which one of those are the valve cover bolts. I think they are small flange. And there's a bunch more--covering every fastener found on the machine.

In the cylinder head section of the manual they don't mention the 12 6mm bolts, only the single 8mm bolt. When a fastener's torque spec isn't specifically mentioned then you default to the "standard" torque specs for that size fastener. Since the head on the 6mm bolts are 8mm, when folks see the 17 ft-lbs torque spec for the 8mm bolt they assume they're talking about the 12 6mm bolts. And walla! You've got the most frequently over-torqued bolts on the 400EX.

Hey........you're everywhere!
Don't worry, you can't torque those that high. Just going to 8 lbs-ft took out the threads for one of the long ones on the chain side. If fact, when I pulled the head to install a time-cert, I found the threads for the other two long bolt holes damaged as well. Ended up installing 3 time-certs and torqued them down to 8 lbs-ft (looks like 6.5 would have been the target) and 17 lbs-ft on the big one in the middle.
And.............it's now out of my garage and in the chassis where it belongs. Bonus!
Thanks!:D

[JOEX]

Thanks for pointing that out GPracer:) Hopefully i'll remember that section in the future. The Clymer manual has it too, along with a bunch of conversions that can be useful:)