Repairs to Yamaha R1 and R6 Nikasil blocks

We have been repairing the first generation R1 and R6 engine blocks for several years now!
These blocks have a thin walled aluminium sleeve which is cast into the block at the time of manufacture.We have seen many of these thin sleeves develop cracks at the tops of the bore possibly from overheating or stress.

R1 cracked


The original sleeves are machined out.
Sleeve removed


The sleeves will be replaced with a specially cast aluminium sleeve which has been pre plated and honed.
Once the sleeves are installed the bores are finish honed and the head gasket surface is decked.
R1 complete
R1 underside