PDA

View Full Version : Engine Noise


426ex
09-27-2005, 05:40 PM
Need some help. A friend got a 400 ex that supposedly has an older 440 kit with a new piston. Motor is pretty noisy at idle. Checked & set the valves (intakes were at .010 & exhaust were at .040...now at .004 & .005) and it quieted down some. Used the screwdriver to the ear trick and I don't think it's in the lower end...sounds like maybe piston slap? Maybe a wrist pin? It gets real quiet when under power or when idling above 1500 RPM....any ideas? Sorry guys, I posted the same thing in suspensions.
426ex
09-27-2005, 05:55 PM
bump
426ex
09-27-2005, 06:02 PM
Anyone????? I know there are some pro's on here....ideas?
426ex
09-27-2005, 06:15 PM
Could sure use anyones thoughts
RiderTRX400ex
09-27-2005, 08:44 PM
give em some time.. people will reply..

if the motor has an aftermarket cam, that could be some noise.. or the cam chain may be worn..

few ideas..
keihin fcr
10-01-2005, 01:53 PM
we bought a 1996 300ex we could get it to fire unless we pulled it and dropped the clutch. This thing was spewing oil bad through the breather tube.We pulled the top off and the ring lands on the piston wear smashed and in peices these people got this thing hooottt. We traced the numbers and it was a 330 kit 12to1 compression. Through tearing it apart the whole bottom bearings and top end was #$%^$&. They ran it dry of oil for a long time. We replaced everything but the bottom end bearings. It is really rough at idle and just off idle but it sings great at high rpms. It sounds like someone starved it of oil for awhile.

JUST FOR THE RECORD ALWAYS CHECK YOUR OIL LEVEL ESPECIALLY WHEN PLAYING AT THE DUNES. i FILLED MY 2005 426EX TO THE FULL LINE AND ABOUT 4 DAYS OF RIDING STARTED TO HEAR THIS TICKING NOISE IT WAS RUNNIN DRY OF OIL. i HAD THE JETTING RIGHT IT JUST HAS TO WORK HARD IN THAT SAND. sCARED THE $#@! OUT OF ME. i DIDNT THINK IT WOULD CONSUME THAT MUCH OIL:( I CHECK IT EVERY 2-4 HOURS OF RIDING. THESE AIR COOLED BIKES HAVE TO BE MONITERED CONSTANTLY. GOOD LUCK GUYS
key4202003
10-01-2005, 02:17 PM
i fully agree with the oil cumsumption on the 400EX. it seems that it gets worse with really high rpms. maybe the oil stays in top end and gets shoved threw the valve seals, and into cumbustion due to the preasure of it spitting it up and falling down to the cooler, he** i dont know how the oil system goes but just a thought:confused:
keihin fcr
10-01-2005, 02:26 PM
Thats exactlly right there nothing we can do about it but just watch it:)
QuadJunkies
10-01-2005, 03:13 PM
Originally posted by 426ex
Need some help. A friend got a 400 ex that supposedly has an older 440 kit with a new piston. Motor is pretty noisy at idle. Checked & set the valves (intakes were at .010 & exhaust were at .040...now at .004 & .005) and it quieted down some. Used the screwdriver to the ear trick and I don't think it's in the lower end...sounds like maybe piston slap? Maybe a wrist pin? It gets real quiet when under power or when idling above 1500 RPM....any ideas? Sorry guys, I posted the same thing in suspensions. When you say its an older 440kit, what Cams does it have??? I had the older kit and had one of those bad Cams from Hot Cam, they since replaced mine with the newer one, but I had to tear it down and inspect it.