Forum

[Carlo]

I'm ready to assemble the crankcase on my 1958 500 Twin, and need some help on the proper procedure.
It looks like the conrods are too long to clear the tunnels in the crankcase halves. I've placed the crankshaft into the timing side case, and it appears that the crackshaft had to be tilted slightly before the conrod would clear the opening.
i don't see how this can go together with the four studs installed that screw into the crankcase halves, since the two haves need to be perfectly aligned with one another. Are tge studs to be left out until the crankcase is assembled, then screwed in from the outside?
I don't remember having any problem like this when I assembled an interceptor engine 20 years ago.
Are the 500 twin short stroke conrods longer than the conrods in the 700 and 750 engines?
None of the several service manuals that I have address this issue.

[Mark M]

500 Meteor Minor rods are shorter than 700 ones. You don't say if this engine was complete before the rebuild? What is it's history? Reassembly of the crank in the cases on all the Twins should be done with the crank rotated so that the rods are at Bottom Dead Centre which helps clearance into the case. REgards, Mark

[Carlo]

The motor was in one peice when I got the bike. It had suffered a broken rod (at or near the small end) on the drive side. The rod had been replaced by the dealer, i took it apart because they failed to fix the damage the rod caused to the exhaust cam tunnel. The timing side rod appears to be original.
I initially took it apart under the assumption that one of the bearings had failed because of the grindy noises while turning the engine by hand.the noise was actually being caused by the cam rubbing on the inside of the damaged cam tunnel, which I eventually had welded back to the original shape.
What is the length of the Meteor Minor rods supposed to be? In my trial assembly of the crankshaft into the timing side, I have to tip my crankshaft a bit before the end of the rod will go through the opening even at bottom dead center. This doesn't make sense. I don't remember any difficulty assembling my Interceptor crankcase years ago.

[vince]

Hi, our host list 500 and 700 conrods as having the same centre distance 6.125 inches. Vince