Chain Box Lapping

[DSPTurtle]

There are probably four people on planet earth that will find this video interesting. Three of them are members of this forum

[KTL]

Nice of you to share that. I bet it's something that is very often overlooked by DIY engine builders.

You can save some time and free up the hand holding the sandpaper by using a larger piece of sandpaper and taping it to the glass (masking tape works good). I just use a Sharpie marker in place of prussian blue!

Another consideration for the chain box surfaces is in relation to the heads. If the heads are resurfaced on the combustion chamber side, the chain boxes should be cut the same amount in order to keep the chain box centered/positioned on the cam housing.

Another part worth lapping is the intermediate shaft cover plate. That thing is notoriously not flat. Same goes for Weber carb accelerator pump covers & pump housings.

[DSPTurtle]

Good point on the IMS cover plate! The breather covers are also usually way off too.

[DSPTurtle]

I don't have any "before" pics, but here are "afters" for the IMS cover and the breather...

[Trackrash]

I've done my mag valve covers twice!

[x98boardwell]

I must be the 5th person who finds this interesting. Thanks for sharing, very good idea.

[Dpmulvan]

I too find it important. I always practice lapping on every build whether motorcycle or car