G Day mates
I am building a cafe racer and have run into a problem allready the motor has seased and it turns out the main jurnal white metal bearing has grabed the krank and spun in the housing resulting in damage lukely it happened at a idle so can anything be done to repair it Eg: line bore the jurnal to take a larger bearing, the rest of the motor is in good condition.
Welcome to the forum. Please add your location and your bike's model and model year (NOT year first registered if that's what your paperwork shows) to your profile so that you don't have to remember to tell us every time and we don't have to keep asking when you forget (see Forum Settings link in my signature).
And welcome to the world of antique vehicle ownership (they own us, not the other way around). Your bike is about 4 decades old and may or may not have had all of the maintenance necessary to keep it safe & reliable so it is highly recommended to download the Factory Shop Manual for your model (available through the CX Wiki - link in my signature) and go through all of the service procedures, regardless of whether your bike has reached the specified mileage.
I also recommend looking on all rubber parts with suspicion because rubber does not age gracefully. Check the date codes on your tires and replace them if they are over 5 years old no matter how good they look & feel (old rubber simply cannot flow around the irregularities in the asphalt well enough to grip, especially if it is cool or wet). If your bike still has the original rubber brake line(s) (should be replaced every 2 or 3 fluid changes = 5 or 6 years) I recommend shopping for modern stainless braided ones (they last practically forever and double the life of the fluid). And don't forget things like the rad hoses and the boot between the engine and swingarm (they can crack on the bottom where you don't see it).
The best advice anyone can give you about customizing any vehicle is to get it safe & reliable in more or less original condition and use it for a while before you start making any changes so it can tell you what changes it needs to make it do what you want/need better. That approach almost always results in something you actually want to keep and use but making changes based on style or on what someone else (who may or may not really understand how the changes affect the way it works) has done often results in a piece of expensive yard art that you can't stand sitting on for more than a few minutes and might even be dangerous.