Head gasket needs to be replaced once torqued?

Hi,

I have been working on a WR426F I just recently bought. The engine needed a total rebuild and I have changed all bearings, bought a big bore kit and a used head. After finishing torquing down the head I notice that I have managed to forget to install the cam chain guide that are to be mounted once the cylinder is installed and before the topend.:busted:

So my question to you is: Do I need to replace the head gasket when I unbolt the head to install the chain guide?

Thanks!

Batmobil

The right thing would be a new one.Once i did something like you, and couldnt get a new one unless i wanted to wait 8 days, so used the old one. That is still running.. The gasket have much wear tho..

I don't think it's a problem because the procedure in the manual calls for torquing the head down, then removing the bolts to apply more moly lube, then re-torquing the head. You haven't heat cycled anything yet, so you should be OK.

The right thing would be a new one.Once i did something like you, and couldnt get a new one unless i wanted to wait 8 days, so used the old one. That is still running.. The gasket have much wear tho..

I pulled my head and jug checking for wear and a noise on my YZ426 and bolted everything back together with same gaskets.:busted:( I do not recommend doing this.) I torqued everything to spec and bike is ok even after 4 weekends of fun. These gaskets are pretty tough. Again, even though I did it successfully, I dont recommend it. This is a weekend toy for me. If it went down, I would just ride my other toy till i fixed it.

As said above since it hasn't been heat cycled it'll be fine. In fact mark your bolts before you loosen them, you'll see that they'll actually turn a little more before torquing down/after completing your angle reading. It used to be common to loosen and retorque head gaskets.

Thanks, guys. I got feedback from seller of the big bore kit as well. He said, as several of you, as long as it hadn't been heat cycled yet I could reuse it.

Appreciate your help!

Old thread I know, but this is good news.  I notice some seepage around the head gasket after filling the fluids on my rebuild.. no heat cycle yet so I'm going to use the copper spray sealant and re-torque it.

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