Wellll ,,,,, traditionally / historically , a gudgeon pin is the pin that holds the piston to the connecting rod . AKA , wrist pin . These were press fit , circlip and button retainer that held the pin in the piston .
I'm not sure about this ?
This screen is meant to keep large particles from entering the pump/hydraulic system . These particles , once they get into the system will damage the pump and attack the relief valve and any rotating parts that rely on pressurized oil for lubrication and clearance . If this pick-up is covered and smothers the supply , then you get no oil to the system and everything is destroyed . There are schools of thought that want no screens or similar coverings over the pick-up tube , Me , I like something over it .
When you get this together and bled , pump the brakes a few ( 10) times and see if the brakes release and the wheel rotates freely and effortlessly . If not , see why .
Fudge , it"s midnight or later where you are . disassemble and make absolutely sure you are putting this together correctly . I've never had one of these apart .
Are you sure the spring goes in with the "shiny thing" outward ?
On a rear stand , pump the brakes about 4 Xs . The wheel will not turn . Break the bleeder screw and see if the wheel spins easier .
If it spins easier , the problem is ahead of the caliper . Brake hose , master cylinder or adjustments .
If there is no difference , the problem is in the caliper .
# 1 name everything you have done to this bike involving anything rear of the fuel tank filler . ANYTHING
# 2 how long has this problem existed ?
# 3 are you telling us everything / have you forgotten anything ?