Help me with enigine knocking noises while lugging engine


22 replies to this topic
  • MountainMax

Posted May 10, 2006 - 07:09 PM

#1

I notice if i lug the engine on my new bike (up a gear more then i should be) and crack the throttle the engine knocks something fierce, is this normal? is it piston slap? will it hurt anything, should i keep geared down a bit lower to avoid it? sorry but im use to 2 smokes......

  • Captain Bob

Posted May 10, 2006 - 07:16 PM

#2

You didn't indicate which bike is giving you the problem. Is this your 06 450?

Bob

  • catmanz440

Posted May 10, 2006 - 07:19 PM

#3

Are you sure the motor is knocking. It could be the chain slapping the subframe and swingarm slider. That is very common when lugging those motors.

  • wobblyknobby

Posted May 10, 2006 - 08:53 PM

#4

whatever the sound is, lugging your engine trashes the rod and main bearings. it aint no diesel son..... :ride:

  • Gadsen

Posted May 10, 2006 - 09:26 PM

#5

whatever the sound is, lugging your engine trashes the rod and main bearings. it aint no diesel son..... :ride:

Its even worse on the gearbox, instead of the consistent load one one side (drive) you get the impacting affect, ie cost/drive/coast sides of the gears are beat up. This is east to do with the higher compression ratios, and the pistons rolls past TDC with more violent force from the extra squeeze. Where as a lower compression engine,t eh piston rolls past TDC wi th ease and little impacting, much smoother. With higher compression engines, lugging is OK, but dont load it while its lugging. If you need to get on the throttle, knock it down a gear first or give it a power hit with the clutch

  • odonnks

Posted May 11, 2006 - 02:14 AM

#6

Your probably hearing chain slap like mentioned above. IF you have somewhere save to do this, run a short distance in the same conditions, (don't lug too much -see above) without a helmet. You'll hear that it probably comes from the drive chain hitting the Al swingarm on top. Do not over tighten the chain ! yuo'll have worse problems. There are some easy mods to quiet this up.
I don't condone riding without a helmet, be careful ! This was suggested to me when I first heard it and I have a 1/2 mile long driveway to ride slow and safe.

  • Bamster

Posted May 11, 2006 - 04:54 AM

#7

This has been addressed many times.
http://www.thumperta...ad.php?t=352393

  • Moto5

Posted May 11, 2006 - 09:18 AM

#8

If it is engine knocking and not your chain you probably need a higher octane gas or even a different brand will help sometimes.

  • TimBrp

Posted May 11, 2006 - 09:56 AM

#9

If it is engine knocking and not your chain you probably need a higher octane gas or even a different brand will help sometimes.



It's funny you mention that but in my manual it states to use 99+octane, even in the WR motor. Any truth to that as my WR occassionally gives me that, "DUNG DUNG DUNG DUNG" sound.

  • Beejay

Posted May 11, 2006 - 12:42 PM

#10

This same noise had me worried when I first got mine, I eventually found it was chain slap causing it, but it sure had me worried then.

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  • Numskull

Posted May 11, 2006 - 04:29 PM

#11

Mine does the same thing. That noise is your bike talking to you, it dont like that spot, so down shift or clutch slip or just let off the throttle. But dont do the knock thing. I apparently have gotten used to it and know not to lug it any more cause I havent heard it the last couple rides. :ride:

  • KiwiRacer

Posted May 11, 2006 - 06:28 PM

#12

I've heard all modern 4 strokes make that noise, Its normally the chain slapping the swingarm chain slider, If the motor is loaded a gear high it will make that noise, You can also hear the intake gasping for air, it's all normal just try stay a gear lower. Like most have stated just clutch to get the power on or ride a gear lower on up hill sections.

  • SPDFRK450

Posted May 13, 2006 - 10:51 AM

#13

Make sure your are running premium in it. Premium has a slower burn rate and can withstand higher pressures before spontaneously combusting without the help of a spark plug. If you are running an 87 octane/13 heptane mix, on an engine with a 12.5/1 compression ratio, then the gas will ignite before it hits TDC causing knocking. 93 octane/7% heptane always always always.

  • YamahaWR450FMike

Posted May 13, 2006 - 12:09 PM

#14

my 04 WR450 used to do that until I changed to JD jetting, that fixed everything

  • creeky

Posted May 13, 2006 - 12:11 PM

#15

Make sure your are running premium in it. Premium has a slower burn rate and can withstand higher pressures before spontaneously combusting without the help of a spark plug. If you are running an 87 octane/13 heptane mix, on an engine with a 12.5/1 compression ratio, then the gas will ignite before it hits TDC causing knocking. 93 octane/7% heptane always always always.


I agree, I think you are hearing a pre-ignition condition, also known as "detonation", "spark knock", and "pinging". Even with premium gas, a hot engine can detonate under heavy throttle when the rpms are low.

  • MountainMax

Posted May 13, 2006 - 04:01 PM

#16

I think it may be the chain, im using 91 supreme gas and it only happens when i lug the engine, I took notice today and i can even see the chain vibrating when it hapens. I read the linked thread and am trying to figure out the silicone trick now, but the posted pic is very small.

  • odonnks

Posted May 13, 2006 - 06:26 PM

#17

I was supprised it was the chain. I was certain it was the engine but one short ride without a helmet it was pretty clear wher the sound was comming from.

  • MountainMax

Posted May 19, 2006 - 04:48 PM

#18

It was the chain, I removed the two top screws on the chain cover and cleaned it and siliconed between it and the arm, let it dry, and the noise is completely gone, awesome fix guys, thanks.

  • SJMC_DON

Posted May 19, 2006 - 10:33 PM

#19

It was the chain, I removed the two top screws on the chain cover and cleaned it and siliconed between it and the arm, let it dry, and the noise is completely gone, awesome fix guys, thanks.


You'll still hear it again from time to time, it's perfectly normal and does not mean your thrashin' your bike. 2 WR's in 6 years and I hear it every time I ride, if you race or ride single track fast it will be heard all the time.

  • YamahaWR450FMike

Posted May 19, 2006 - 11:51 PM

#20

I notice if i lug the engine on my new bike (up a gear more then i should be) and crack the throttle the engine knocks something fierce, is this normal? is it piston slap? will it hurt anything, should i keep geared down a bit lower to avoid it? sorry but im use to 2 smokes......


my 2004 WR450 used to do this until I installed the JD jetting and the zip/ty fuel screw. All noises gone now and huals butt!




 
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