I am just about to swap out my 1-1/2 inch OD, 8 inch rise Burleigh t-bars for some ebay ones (demonscycles 1-1/4 inch OD, 4-1/2 inch rise t-bars).

I have noticed that the threads on the new bars seem finer than what has come off.

Does anyone know what type of threads it could be?

Don't want to cross thread these.

 

I have found that the burliegh bars I fitted have needed a tap run though the thread to clean them up, other wise it should be the same size as your orig ones

Get a known bolt and try it or take the bars down to a bolt shop and they will identify the thread and sell you some bolts.

If you know a fitter, he may have screw pitch guages and a verniers to help you, or 

If no one knows you may have to ask this mob.. 

http://sales@demonscycle.com

Definately not the same thread Ando.

Found something about being a 1/2 inch fine thread so will see what the fastener guy's think monday.

Thanks guy's.

Harleys have mixed up a few different thread sizes in different spots but they are all standard imperial UNC (coarse thread) or UNF (fine thread). These are mostly available at your local Bunnings. Take the bolt you have to check what size it is and get the same size in the opposite thread.

Yep UNF (united national fine) or UNC ( united national coarse)
Riser bolts are usually UNC but have seen some UNF ones

Make sure you get grade 8 bolts, UNF usually is anyway