Siebenrock 1000cc Power Conversion Kit for R75, R90, R90S Models ('70-'75)
Up to 10 HP power increase for 1970-09/75 with 97mm block bore.
Just exchange Cylinders+pistons - nothing else has to be modified.
FITS: From 1970-75 up to 09/75 production date (97mm block bore)
Dual plug ignition is recommended due to higher than stock compression ratio to prevent damaging pre-ignition, also known as pinging. Low compression base gaskets are available (Part # 1111092) which lowers compression to 8.8:1 which is suitable for single plug ignition.
Standard valve cover gaskets are recommended unless you have damage or warpage at the valve cover sealing area in which case we recommend our silicone valve cover gaskets.
If heads are being overhauled at the same time, 40mm exhaust valves should be installed. We are experts in cylinder head work at Beemershop.
Kit is complete except for special top end gaskets which can be purchased below.
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