mugello 186 kit fitted with 60mm GP crank

[watto66]

Hello All ,

Can somebody please help.

just about to rebuild the engine on a restored LI 150 special been offered a new MEC 60mm GP road race crankshaft , brand new off of a mate.Got a static electronic kit for a GP taper already working on the engine with a standard italian GP crank' going to try and use 26mm carb' with remote filter. Cylinder wise i bought a new V4 mugello 186 kit a few months back, i have spoken with a couple of dealers who stock this and are saying i can use the 60mm stroke x 107mm conrod crankshaft as long as i use a 1mm packing plate at the base of the cylinder does anybody know do i need to change the cylinder head ? the one i have came with the kit with the 3 additional location studs i dont know if i am getting confused with 192cc kit set up , or would i be better off waiting and getting a 58mm stroke x 107mm conrod.

Any help would be greatly appreciated.

[Darrell Taylor]

if you fit the long stroke crank check the piston clears at bdc ,the 60 crank will give a bit of extra capacity which is free power if you have the choice it will result in the head being slightly higher compression but could be corrected by increasing the squish clearance by approx 0.2mm,the bigger squish can be achieved from head gasket thickness of which on the v4 be better to add the extra 1mm packer to the head instead of the base gasket to allow for the longer stroke.