NOS Suzuki RM 400/370 connecting rods, $225 USD each, I pay the shipping worldwide, buy 'em all for $700 USD shipped worldwide FREE!
RM400 N/T (last one) , RM370/400C (3 on hand), the 370 rod will also fit 400's all years. The only differences are the 370 rods use oil slots on the big end instead of holes and the needle bearing is 18 x 22 vs 18 x 24, for reference a 490 Maico uses an 18 x 22 bearing so no worries here on a 400 either.
Rods will be sent with appropriate small end bearing included.