If the engine is at all modified, I reckon you should think about using better flywheel bolts. Some of the Japanese ones are pretty crappy. I use capscrew (they are a far better grade of steel) from one of the bolt suppliers. The Bolt Bloke is OK.
Loctite them and pull them up TIGHT.
You might have to get the back of the flywheel machined as well.

found the problem

my flywheel fell off lol snapped all the bolts
me needs a15 crank

Did you use the throw out bearing from the old (unknown) Sunny box??

If the noise only happens while the clutch pedal is pushed down, then it's time to buy a new throw out bearing (the thing that's moved around by the clutch fork). Try the one from your other box?? It might be the same.

Chris

i just replaced the clutch in my 1200 and put a sunny gearbox in and i have a really bad noise. when i take off at low revs it makes bad crunching noises but under load its ok (when clutch fully out under accelleration). when i down change it sounds like my starter motor is jammed on but i took the starter out and the engine still has full power and clutch grips good
any ideas