STRANGE FIBRE SUBSTANCE ON CB750 OIL PUMP FILTER

[sticks]

hi all
a couple of questions regarding my cb750 k6,the engine was rebuilt by the previous owner about 1,500 miles ago,so gave it an oil and filter change yesterday,i also removed the sump,on the oil pump filter there was a strange fibre subtance,almost like wool,also on the sump pan there were small black bits,i cant realy believe that they could be from the tensioners as i hope they were replaced,i could view the primary chain tensioner and it looked new,i also noticed that the return oil pipe has a kink in it,i have heard that they can break up internally,could this be the cause of the black bits,one final point i seem to have fuel coming out of the air box,could the float need adjusting,and could the overflow pipe on the carbs be blocked,the engine runs as sweet as a nut with no untoward rattles apart from the usual clutch,should i be worried about the stuff in the sump,as i dont fancy an engine strip,sorry for such a lot of questions.any advice and help would be appreciated. am lookig out for a pair of oil pipes,new ones dont seem to be available any more.
thanks
Dave.

[Spitfire]

Hi Dave,
           If the engine has been apart you could expect some bits of debris to be flushed out into the oil pan, bits of cloth, carbon, jointing compound etc. Check again next time you change the oil and see if it re appears.
Fuel coming out of the air box has to be coming from the carbs either an overflowing float bowl or fuel blowing back. If as you say it is running fine then probably not the latter.  Does the petrol appear when the bike is standing still or after a run ? Do you turn off the fuel tap when not using the bike.
I would check that you haven't got a sticking float or some crap in the needle valve before playing with float levels. On my F1 I found that there is a filter on each carb, you have to unscrew the needle seat to get at it, mine were full of junk.
Hope this helps

Cheers

Den

[sticks]

Hi Den
Thanks for the reply,had the carbs apart last night,one of the float settings was miles out,and the overflow pipe in the float bowl was blocked solid,so i would imagine it was filling up and spilling into the filter,and i suppose into the engine,i turn the fuel off when not using the bike,exept when out on a run,it has a new tap fitted.
thanks
Dave.

[DuoDave]

I found the same thing when I took the sump plate off my cb750. A weird mass of fibre almost covering the filter mesh. I have no idea what it was. So what's that all about?

[hector2800]

Same here on my F2. I wondered if it was cause someone had mixed synthetic and mineral oil.