Replacing Needle Bearings

[Al Hobbs]

CMB, Kalistratov and MAC 67, 80, and 90 engines use needle bearings at the crankpin. It is not difficult to replace them. I count out exactly how many needles are to be installed. I either use Rislone oil or cable grease to hold the needles in place while I install them. This helps to hold them in place until all of them are installed.

Use plastic forceps to prevent magnetic attraction.

Once they are installed, I count them again to make certain one of them has not fallen out and into the crankcase. If one is missing around the crankpin, start all over, removing all the needles, including the lost needle.

A loose needle bearing will destroy the piston and sleeve when you start the engine in seconds.

 

[timothy johnson]

PM sent for order

 

[Mark Anderson]

Mark Grim showed me a tool that he uses and I made my self one. A piece of brass tube about 3 inches long that the needles fit nicely in. A piece of wire the same size as the id of the tube with a little tab bent on one end. load the tube with greased needles leaving about a 1/2 inch empty to start the wire. Hold the tube with your thumb and second finger. push on the end of the wire with your index finger to insert the bearings.

 

[Martin Gruber]

To hold the Needless in Place,You can use Vaseline.

For the Picco 90XP i need 25 Needles with 2mm Diameter.The Big End Bore is 13mm.

It is very important,that the Needless are from 1 produktions Charge - Batch,so the Diameter is the same.

Deadly for a bearing is,when some Needless are bigger than the Rest.

1mü + is the max.Better is 0 or -1mü.

I have buy a used Picco Engine.Tha Crankshaft was new overhauled.

I have Pressd the Crankpin out and Meassured all Needless.

5 Needles are 0,005mm wider than the Rest.So this 5 Needless running hot and go down and then the Rest from the Bearing.

Regards,Martin