Engine Knock

[Lightweight BigDog]

03 Pitbull with 107 motor. 20K+ miles. Religiously changed the oil etc. Mobil1 and ridden modestly, rarely above 3-4000 RPM. Recently changed the stock exhaust to V&H sideshots. Thats the only mod. I often ride with a full face helmet and noticed the other day when riding w/o a helmet(or think I noticed) a knock coming from the motor. Placing my hand on the air filter while idle I feel something as well. Bike pulls strong and at speed hard to really tell. I do notice a change in the "tone" of the exhaust after it is warmed up as well. Cold start has a nice throaty growl to it. After it is warm it sounds more like a damn Honda-Harley wanna be with a mild pop to it. So...... Just looking for advise on what to look for, listen for, feel for etc. Is there a cam sensor that can be replaced or perhaps something in the exhaust that could be causing this? Thanks in advance for any input you may have and much appreciated. :2thumbs:

 

[barhopper]

Not a cam sensor. When is the last time you adjusted your valves?

 

[Five Five]

tear it down .... went through this on my 03Pit, I refused to beleive I had rod bearing failure at 28K miles.... after I danced around every other potential cause, I tore it down and the front rod bearing was wiped out, pieces of roller bearing in the bottom of my crankcase....crank pin had a .100" deep groove wore into it..... Keep in mind that S&S did not build our motors... they were sold as kits to BDM and they assembled them.

PM me if you want to talk through it...

 

[barhopper]

You just killed him with that news Bill.

 

[bigdogtech01]

Not a cam sensor. When is the last time you adjusted your valves?

No valve adjustment needed with hydraulic lifters, but could have a lifter going or already bad. They do go bad from time to time. Sometimes do not pump up or the roller on the end, the bearings go bad. Might want to check into it ASAP. If the roller is bad, it can take out the cam lobe. Just one gasket to replace under the cam cover to look at the cam. Otherwise, remove all pushrods and lifter blocks to inspect the lifters.

 

[Five Five]

You just killed him with that news Bill.

Sorry lightweight didn't mean to ruin your day ....try a valve adjustment and check you valve train etc ....couldnt hurt...
:2thumbs:

 

[MARV]

No valve adjustment needed with hydraulic lifters,

really?

 

[Little-Boo]

There is a difference between a knock and tic tic that is cause by a bad lifter. If it knocks it has to be bearing failure, piston slap, worn wrist pin. It is easy to find that, start the motor and pull the front plug wire if it's the front cylinder the knock will get louder. Do the same to the rear cylinder. If no knock then look for something loose that is hitting metal on metal. If it knocks take her down to the last bone and rebuild.

my :zz2cents:

Carlos

 

[Lightweight BigDog]

Sorry lightweight didn't mean to ruin your day ....try a valve adjustment and check you valve train etc ....couldnt hurt...
:2thumbs:

No didn't ruin my day, from what I was hearing I figured it was a rebuild deal worst case. Kinda hoping for the best, expecting the worst. I'm taking it all in right now and over the 3 day weekend do some inspecting etc based on what I'm reading here. Thank you all!

 

[Lightweight BigDog]

tear it down .... went through this on my 03Pit, I refused to beleive I had rod bearing failure at 28K miles.... after I danced around every other potential cause, I tore it down and the front rod bearing was wiped out, pieces of roller bearing in the bottom of my crankcase....crank pin had a .100" deep groove wore into it..... Keep in mind that S&S did not build our motors... they were sold as kits to BDM and they assembled them.

PM me if you want to talk through it...

Just read your post regarding your rebuild. That helps allot. I may take you up on the help with the rebuild as I have my checkbook smoking right now with other projects! Thanks!:2thumbs:

 

[Five Five]

Just read your post regarding your rebuild. That helps allot. I may take you up on the help with the rebuild as I have my checkbook smoking right now with other projects! Thanks!:2thumbs:

No problem Stacey..... contact me via e-mail if needed:
bill@myperea.com

 

[BadBrad]

Do you hear the knock when you first crank it up? You talk about the difference in sound from your pipes after the bike warms up but didn't really say if the knock only starts after the motor is warm. I would think that bad bearings would knock hot or cold. If it only knocks after it warms up, could be something related to low compression on one cylinder. Like Carlos mentioned, pull the plug on one cylinder at a time and try to narrow down your search to one cylinder. If you have a locking nut coming loose on a pushrod, hydraulic lifters can't compensate for that, but eventually you'll lose total power in that cylinder with a total collapse of the pushrod. A total tear down of the motor may not be necessary.

 

[bigdogtech01]

really?

Yes, if the motor is to the point that it needs the pushrods adjusted, it's time for a valve job. Normally you wil not need to do anything for valve adjustment. they are self adjusting via the hydrulic lifters. If you have your motor apart for any reason, it's always a good idea to brake the push rods down and adjust to factory spec. Otherwise, there is no need to adjust.

 

[Lightweight BigDog]

Do you hear the knock when you first crank it up? You talk about the difference in sound from your pipes after the bike warms up but didn't really say if the knock only starts after the motor is warm. I would think that bad bearings would knock hot or cold. If it only knocks after it warms up, could be something related to low compression on one cylinder. Like Carlos mentioned, pull the plug on one cylinder at a time and try to narrow down your search to one cylinder. If you have a locking nut coming loose on a pushrod, hydraulic lifters can't compensate for that, but eventually you'll lose total power in that cylinder with a total collapse of the pushrod. A total tear down of the motor may not be necessary.

Brad

I will do as Carlos instructed to narrow it down if possible. It seems as though the knock is more so when warm/hot. That's what made me turn around on my last ride. Took off sounding and feeling good, next couple of lights/stops it became more apparent in sound only. Bike ran and pulled good just the knock made my stomach sink. Will investigate over the weekend and determine the cylinder, then drink away my tears!

 

[johnstonad]

03 Pitbull with 107 motor. 20K+ miles. Religiously changed the oil etc. Mobil1 and ridden modestly, rarely above 3-4000 RPM. Recently changed the stock exhaust to V&H sideshots. Thats the only mod. I often ride with a full face helmet and noticed the other day when riding w/o a helmet(or think I noticed) a knock coming from the motor. Placing my hand on the air filter while idle I feel something as well. Bike pulls strong and at speed hard to really tell. I do notice a change in the "tone" of the exhaust after it is warmed up as well. Cold start has a nice throaty growl to the used car engines for sale. After it is warm it sounds more like a damn Honda-Harley wanna be with a mild pop to it. So...... Just looking for advise on what to look for, listen for, feel for etc. Is there a cam sensor that can be replaced or perhaps something in the exhaust that could be causing this? Thanks in advance for any input you may have and much appreciated. :2thumbs:

Yes there is a cam sensor that fits your need. I would recommend you to my friend. He surely have it.

 

[woodbutcher]

MAKE SURE IT AIN'T YOUR VENT TUBE IN THE GAS TANK THAT HAS COME LOOSE!!!!!!:2thumbs::2thumbs::2thumbs::roll::roll::roll::roll::roll::roll::roll:

 

[Lightweight BigDog]

Shattered Lifter Block

One of the lifter blocks broke into two pieces and fell to the bottom of the motor. I have no idea what could have caused this! Metal fatigue? So plan now is to replace both lifter blocks, new rollers and new gasket set .... any thoughts or further opinions would be appreciated. Thanks! The picture is attached.

 

[chacha]

Dude, that is f'n crazy! Never heard of this one...thanks for the picture!

 

[BadBrad]

Dammit man! That's the first I've seen of that. Were you able to recover all broken pieces? The worst of your problems may not be over. Never heard of the tappet block breaking, but the good thing is that you did find it. Now, just find the rest of the broken pieces.

 

[spadesluck]

That just looks like it was probably a factory defect. I would not think there is to much force on the blocks for that to be a problem. Just make sure you get all the chunks and go about your business.