Is this Normal

yz125_894

Member
Nov 23, 2003
42
0
I have had my 02 yz125 ported and polished and i was out riding it the other day and i noticed sthis strang sound. When the bike it in like 4th or 5th gear about midway through the rev it makes a noice like somthing if flapping but then it goes away as you get to hig RPM. i have torn the top end apart nothing took the reed valve apart still nothing and i checked all the bolts and nothing is loose. What the heck is this "flapping" noise i hear. There is no power lose or n e thing soo i dont know.

-Pat-
 

yz125_894

Member
Nov 23, 2003
42
0
I thought it might be the reeds "fluttering" too. How do i fix this or is it just something that happens. Also is it a big deal to anything?
 

jsproch

Member
Oct 23, 2002
7
0
You may want to check your powervalve to piston clearance. It is uncommon but sometimes the ring will come into contact with the powervalve at low revs(closed) causing a "tapping" noise.
 

Studboy

Thinks he can ride
Dec 2, 2001
1,818
0
Or....the bike pinging under the load? What fuel is the motor setup for and what fuel are you running?
 

yz125_894

Member
Nov 23, 2003
42
0
My bike is set up to run on premim octane. i was talking to eric and what he said was is was with eraly detination or something to that effecct cant rember for shure but it had to do with worn plating and stuff. so i traded him my cylinder for another one.