rattle...?

shudna · Post by **shudna** » 26 Dec 2006, 16:21

As I said b4 my engine has a rattle,could be piston slap,small end ,etc.
I've stripped it and it all looks ok,I'll get it measured and stuff order new rings,small end,etc as a matter of course.
I did enquire b4 and was told the noise could also be the balance shaft bearing;I've pulled that out and the bearings also look ok(still in situ' though)...how hagged do they have to be b4 they rattle.
It becomes more pronounced on the rev down rather than when reving up..any help??
Cheers.
P.s looking @ it it looks as if it's never been apart...

edarter · Post by **edarter** » 03 Jan 2007, 17:00

have a look on the balance shaft itself - it there is marking where it rests in the bearing thats where your noise is coming from. Mine is the same but I can't be bothered to change it yet. As a mate of mine said though, with regard to the wear on the shaft - if you can feel it you can hear it ! Doesn't have to be much at all, mine is almost mistakeable for a discolouration but is very slightly worn.

slider · Post by **slider** » 24 Feb 2007, 18:36

ayup shudna,did you manage to correct the rattle if so what was causing the problem?
just been talking with mickstoy about it cause mines doing exactly the same thing and he'thinks he may have heard his do it aswell.again it only does it when the revs drop,the motor has done 120 miles since being rebuilt by my mate at his bike buisness and we put new bearings in top & bottom just as a precaution.the motor runs sweet as a nut with no noise when i accellerate or when at cruising speed.
i was wondering if it was the power valve chattering as it closes.any help would be appreciated mate

shudna · Post by **shudna** » 24 Feb 2007, 20:09

Checked out the balance shaft that was ok..
Checked the piston to bore and the bore was near enough oval;never had a rebore in it's life,luckily Forrest Gump who had it b4 me (dinked fork legs remember

) never took it apart.
Yeah mate it was piston slap.
Got a little clutch rattle now but I won't worry about that..m.o.t-->monday.
Sorry m8 I've been no use at all

.

slider · Post by **slider** » 24 Feb 2007, 20:19

cheers anyway shudna,didn't do a rebore as my mate said it looked like it'd been recently done,new piston,honing marks on the cylinder and the head was virtually clear of any coke deposits.better trawl through some more old posts see if i can get any clues

shudna · Post by **shudna** » 24 Feb 2007, 22:20

Not being funny m8 but you should've measured the bore clearance.
They can look very good for a very long time,you'll kick yourself (or your m8

)if it turns out to be that.
Check for the correct tolerances and then get it checked;someone on here could tell you the tolerances;failing that LT or any good engine/motorcycle shop...
Don't take much to cause slap and it does tie up...

Good luck.

slider · Post by **slider** » 25 Feb 2007, 02:46

mmmm,got me thinking so i rang him earlier,he assures me that there was no play between piston and bore.he's been a bike spanner for 15 years and i've had engine repair work done by him b4 with no probs i would of thought he would pick up on something like that.i'll do a bit of investigating but if does turn out to be piston slap,he'll be gettin a thorough spankin.

shudna · Post by **shudna** » 25 Feb 2007, 10:30

Not knocking anybody's work but my made measured with feelers guauges your talking about thou

.