noise

[digsaw]

87 cbr400r making tapping noise,sounds like its at engine speed on one pot,its comming from the bottom of the engine but once you are underway it seems to go away.Its only done 42000k but hard .Can you get at the bigends by taking the sump off it and replace the bearings with the engine still in the frame :spudwhat:

[Jackrat]

No you can't,no way.
A big end normaly sounds like a deep knocking.When you give it a little gas an then back off you will hear it the eazyest.
A tapping noise could be any number of things and where you think it's coming from may not be right.Noise in motors has a habit of travelling.
Use the screw driver to the ear trick to try tracking it down.
At those kms I would suspect Cam chain/tensioner or Tappet/valve adjustment.

[digsaw]

tappets been checked,all ok there and cams gear driven and it sounds just like you say and i think you might be on the right track jack

[digsaw]

jackrat i did the screwdriver thing and it would seem that the noise is comming from the cam gears,at the top in the middle.hope sombody out there has come across this problem and has info on what and how to fix

[Bonez]

jackrat i did the screwdriver thing and it would seem that the noise is comming from the cam gears,at the top in the middle.hope sombody out there has come across this problem and has info on what and how to fix

Could be an inboard exhaust (cyliders 2 or 3) valve is on the way out or tappet clearances out. May be an idea to get a compression test done. When was to last time it had a servicing?

[digsaw]

serviced just before the noise started,tappets done,full service an comp test done at same time,all was good.

[Rback]

Could be 1 of 2 things wrong with your bike.
A tappet could be loosening up or one of the backlash gears on the cam gears have worn out. Pay to get it checked.

[Bonez]

serviced just before the noise started

Have you pointed this out the the guys who did the servicing?

[Jackrat]

Time to go back to the shop mate.If your short on the readys you should make clear to them that you only want it diagnosed.
You have a lot of things that might be causing your noise,but won't affect your compression much.
Small end/con rod bearings/bushes,Cam bearings/bushes,cam drive bearings.
The way you describe it,my next guess would be small end/con rod bearings/bushes.the location is about right and it goes away as the engine heats up.In the early stages that is.In twins the main bearings normaly sound worse under decelaration,the small end bearings/bushes under accelaration.
I'm just assuming multi's would be the same.
If you do take it to a shop,be aware that they may not be able to give an accurate diagnosis without taking things apart.Once they have taken it apart they may not be willing to put it back togeather if it's going to destroy your engine/hurt you and bring bad vibes back on them.
Sorry I can't be of more help.
Good luck.