Crank Seal R3


R3 crank seal (smaller id)

19 in stock

SKU: BP0013 Category:


Crank seals are important for 2-stroke engines to allow transfer of the fuel-air mix into the cylinder and to keep the chain drive or gearbox oil out of the crankcase.

Early engines were build with collar and ring seals but these were later replaced with a sleeve and poly lip seal.  The seal part number (this part) is 15053 and is a press fit into the housing but to convert from ring a collar, additional sleeves are also required over the crank: 15023D at the driving end and 105023B at the driving end.

Note that this poly lip seal is a slightly smaller internal diameter than the original part (this seal is 1″).  These were the seals I was taught with, were sold by other vendors before me, and are preferred by some…but I do now use the original specification ones myself and prefer to replace worn sleeves where necessary rather than using undersized seals.  The original specification seals can be found in this shop here:


Additional information

Weight 7 g
Dimensions 4 × 4 × 0.5 cm