Originally Posted by chasbmw
My 1070 kit is fine after only 10000 miles or so, these kits have been around for many years now and I have never seen any chatter on the Internet that indicated that there is a problem. A new casting for the cylinders is very different than just fitting a liner to an existing cylinder as that used to be done with the old 1050 kits using venola pistons.
The Seibenrock kit in includes new longer conrods and a very nicer assymetrical cam and the components work very well together. It's not cheap though
I have started threads in two german forums asking for feedback regarding longevity of the 97mm (e.g. HPN) and 98mm (Siebenrock) kits.
Response was poor regarding the number of answers.
However, content of responses was positive through all posts.
Mileage varied between 10,000 miles (Siebenrock BBK) an 100,000 miles (HPN 97mm or others).
No problems reported.
I'm wondering why gasket surface should have decreased with bigger bore.
The head gaskets don't use the whole surface, just a small rim around the bore.
And at the cylinder base the surface is the same.
Or am I missing something?