by xlh59 » Tue Nov 20, 2018 2:09 am
If you want to use XL parts for crankpin and rods, I would not change any bearings or shafts. First of all, the XL shafts will not fit into the KR flywheels. Although the taper angle seems to be the same, the depth is somehow different. But the KR shafts do have another big benefit over XL shafts: The use metric bearings and the rollers do not run on the shaft, meaning wear on this shaft is rather not commen (unless a bearings starts spinning on the shaft). Even if a shaft has pitting, you can refurbish it for ball bearings, which is not possible if the rollers run on the shaft.
The early XL flywheels used steel thrust washers and I think T&O also used steel. All you need to do is machine thrust washers of the right depth and fill the recess in the flywheels that is supposed to give room for the KR roller cages. That is all mechanical change that is needed to use XL rods in KR wheels -- very simple. YOu can use steel or brass as material for the thrust washers. I just bought a connecting rod set (the japanese ones) for my XLH that came out of the dixie stock, whichj is all over Ebay now. I really like the quality, and the prices are very very competitive. YOu would not even get used KR roller cages for that price.
now talking about balancing:
I had to balance my KHR flywheels with a counterweight of 1101g using pistons with a total weight (including rings, pin, clips) of 430g which is propably close to a KR piston assembly. My current XLH had to be balanced with 1048g with the japanese rod set and piston weight of 560g -- you can imagine, that lighter pistons will even reduce the counterweight of 1048g. Both times I used the same balancing factor. As your KR flywheels have been balanced for the heavier rod setup, you would need to remove material from the flywheel.
To give a rough estimation: If you need to reduce the weight by 50g, we are talking about 2" in lenght of a 1/2" hole ... seems possible to me (depending on how many holes the flywheels have already).