Reading this might save you a lot of hassle.
This is a sorry tail of missing something simple that has cost me many many hours of pissing about .
I bought a GK76A a while ago that had blown an engine (piston / valve mash up) it had already been fitted with another motor that I got fired up after much electrical & carb problems but it smoked badly when hot!
So I had the head off it & replaced the valve seals, head gasket etc, checked the pistons, rings, bores etc reground the valves & rebuilt it....
It all looked good and was running fine untill it got nice and hot then it started smoking again WTF
so I left it in the back of the gararge for a while and got pissed.
I thought the rings or barrels must be toast although they looked in very good condition.
So I managed to track down a bike for spares with a running engine and did the swap connected it all up got it running and it all looked good
I took it out for a run and guess what? It bloody started smoking again AAARRRRGGGHHHHH Bol*#ks should have got another FZR etc etc!
Anyway I was crying in the gararge that afternoon when I noticed the exhaust can was dripping oil out of the small drain hole at the bottom and thought if it's burning that much oil then surely it shouldn't run as well as it does, so I took the can off and saw that it was pissing wet with oil at the exit end but perfectly dry on the inlet side also the downpipes were perfectly clear??? Now you dear reader may well have worked out what's going on here,
Mmmm I thought lets try a different can on it to see what happens and it only ran perfectly on a 40 mile run with no smoke at all!
So the morale of this story is if you by a bike that has blown an engine and puked loads of oil into the exhaust system,

CLEAN THE BLOODY EXHAUST SYSTEM OUT BEFORE YOU REBUILD THE NEW ENGINE FOR NO REASON!

Thanks all you guys that gave me help here with good info on all things GSXR.

Dobbs.

looks like you haven't had any 2 stroke experience

glad your sorted

Oh I've had plenty of two strokes ah the simplicity, I even took the thing up to an old airfield the "get it hot" but that still didn't do the trick. that last engine must really have shit itself!
Will try some caustic soda & petrol later.

goto your local motor factors (not halfords) buy some engine degreaser 5ltrs for about £15 it is water washable. Put some in the exhaust shake it around. leave it a while. empty it out flush with a hose. then heat the exhaust with a blow torch. get it nice and hot if it smokes wash it out again. don't use petrol for this or you'll set light to the fuel.

"don't use petrol for this or you'll set light to the fuel."

That's the least it deserves.

Mine should be back on the road soon enough and shat its entire loads of oil out in a very large blue cloud when it went bang, I'll be sure to give them a damn good clean through first!
CHEERS!