My betor forks are making a loud bang when lifting the front end . I have stripped the forks down and see no problem any help would be appreciated 

I'll ask the dumb question.
How much and what weight oil are you using?

I am using 10 w oil and 220 ml per leg

Rule of thumb, topping out = to little oil.

I don´t know about your forks but there can be a short spring working in the opposite direction preventing  problems with bangs when fully extending the forks. Ought to be some form of device, hydraulic or mechanical.

I had the same problem with my 125 but with Marzocchis. I put them back together incorrectly. All documented here on this forum.

I had the short spring, as Carl said above, on the wrong side of the top washer and circlip.

Phil

There is a short spring I stripped the forks and rebuilt them the same way the problem could have been there . I have looked at the parts diagrams and can’t see anything missing I am going to try a heavier grade of oil . Thank you for your input keep you posted ?

Should have 180mL per leg in the 125. i wouldn't think an extra 40mL of oil per leg would cause it to top out.
If it has always been like it since you've owned it the bump stop could be the problem.
If its only just happened my guess is oil. either amount wrong or weight.

what’s missing ?