Replacement cylinder Jug

[allen standley]

OK Grubee GT5. blew out the wrist pin,bearing. Needed cylinder, Piston, retainers, and all gaskets. Head o.k. Bought all replacement parts from Kings where the engine was origionally purchased in april 2011. Now --The carb manifold will not bolt up to the engine due to the fact the replacement cylinder on the input side (carb Side) is cut to accomodate a muffler. Yeah it's true! How can a screw up like that happen? Anyway I was fortunate enough to have a muffler to cut the flange off, now I must take off the alum. manifold and replace it with the old style steel one with the muffler flange welded on to it. Also the actual wrist pin was too long by about an 8th of an inch. So grinding the wrist pin shorter to fit was not a big problem. Has anyone experienced this situation before?

[Al.Fisherman]

I have never even seen a post of this problem since I've joined this or any other bike forum. So you are saying that both the intake and exhaust stud holes have the same measurement?

[Greg58]

Hey Allen I found on the grubee site that the "G" style rist pin clips were the cause of some engine failures. These have now been replaced with the standard "U" shaped style. As for the large intake port I have heard of new engines having larger ports, if you could find a intake that was that size it would perform better.
Grubee Inc.

[biknut]

Sounds like you got a cylinder with 40mm spacing on the intake studs. Most have 30mm spacing. Manic Mechanic makes a 40mm manifold.