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Discussion Starter #1
So now that I have my vstar 1100 running perfectly and nice and quiet, i can now hear a very subtle quiet knocking coming from the engine. Doesn't happen all the time, only during certain rpms. Like when cruising in third gear in town, at a certain speed/rpm, i'll start to hear the very faint noise of knocking. Also, not a knocking from lugging the engine.

Sooooo is it a rod knocking? And if it is a rod knocking, would it only happen during certain rpms? Like i said, it comes and goes, and i only hear it because i'm ocd with my bike and how it sounds lol. When it happens, if i keep it at the same rpm, it will continue knocking. If i increase/decrease the throttle even by a little bit, it goes away.
 

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I had an aircooled VW many years ago that had a bad connecting rod when I got it (saleman told me it was the exhaust)

I drove it to college for a year that way till it finally broke loss and smashed the piston into the head.

The thing I observed is I could hear it the best while holding a steady speed, or just slightly letting off the gas at a steady speed. I think the reason is that is when the piston is being pulled in both directions by the crankshaft with no real force on it - the expanded fuel is not pushing it down, and the compressed air is not holding it back on the exhaust stroke, so the bearing hits the rod at both the top and bottom of the strokes. Sounded like shaking a coffee can with a metal ball bearing in it.

You just adjusted the valves, where any of them tight? its possible you did not tighten the lock nut down on one of them and its coming loose, making the tappet noisy. But a tappet should sound the same all the time.

If it is a connecting rod you dont want to let it go for long, because the oil lubrication system depends on all the bearings being sound with the correct clearances. If you have one bad bearing the oil pressure will leak out thru that one, dropping the oil pressure for the entire engine, and soon all your other bearings will wear because the pressurize layer of oil between the bearing and the rotating surface is not as high as it should be.

On my VW the oil pressure light would flicker when the engine was hot and idling. I dont think there is a place to add an oil pressure sensor on the engine, or if a slightly knocking rod bearing would drop the pressure enough to notice, esp since you would have to know the idle speed oil pressure for a good engine with the same weight oil.

This might be a case where an experienced mechanic with trained ears needs to take the bike for a ride.
 

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Discussion Starter #3
I had an aircooled VW many years ago that had a bad connecting rod when I got it (saleman told me it was the exhaust)

I drove it to college for a year that way till it finally broke loss and smashed the piston into the head.

The thing I observed is I could hear it the best while holding a steady speed, or just slightly letting off the gas at a steady speed. I think the reason is that is when the piston is being pulled in both directions by the crankshaft with no real force on it - the expanded fuel is not pushing it down, and the compressed air is not holding it back on the exhaust stroke, so the bearing hits the rod at both the top and bottom of the strokes. Sounded like shaking a coffee can with a metal ball bearing in it.

You just adjusted the valves, where any of them tight? its possible you did not tighten the lock nut down on one of them and its coming loose, making the tappet noisy. But a tappet should sound the same all the time.

If it is a connecting rod you dont want to let it go for long, because the oil lubrication system depends on all the bearings being sound with the correct clearances. If you have one bad bearing the oil pressure will leak out thru that one, dropping the oil pressure for the entire engine, and soon all your other bearings will wear because the pressurize layer of oil between the bearing and the rotating surface is not as high as it should be.

On my VW the oil pressure light would flicker when the engine was hot and idling. I dont think there is a place to add an oil pressure sensor on the engine, or if a slightly knocking rod bearing would drop the pressure enough to notice, esp since you would have to know the idle speed oil pressure for a good engine with the same weight oil.

This might be a case where an experienced mechanic with trained ears needs to take the bike for a ride.
Yeah when I adjusted the valves, 3 of them were tighter than spec. Had to loosen all 3 and set them and readjust. The noise was there before the valve adjustment. But it started after running the bike at max speed for 15 mins, that one night. So I think the rod bearing turned or got worse.

I'm guessing it's not an easy job to get in there and change the rod bearing eh? hahah
 

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So now that I have my vstar 1100 running perfectly and nice and quiet, i can now hear a very subtle quiet knocking coming from the engine. Doesn't happen all the time, only during certain rpms. Like when cruising in third gear in town, at a certain speed/rpm, i'll start to hear the very faint noise of knocking. Also, not a knocking from lugging the engine.

Sooooo is it a rod knocking? And if it is a rod knocking, would it only happen during certain rpms? Like i said, it comes and goes, and i only hear it because i'm ocd with my bike and how it sounds lol. When it happens, if i keep it at the same rpm, it will continue knocking. If i increase/decrease the throttle even by a little bit, it goes away.
Can you try the old large, long, wooden handled screwdriver as stethoscope trick? Put the blade here and there on the engine, handle to your ear, vary the throttle up and down and maybe pin point the source of the noise? It may also help identify it. Amazing how much it helps with internal clicks and clacks.

If it doesn't do it while not in gear, that may also be a clue.
 

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What weight of oil are you using. Did you go down on viscosity? Older engines with looser bearings will start to knock going from 20w50 to a 20w40. I nursed a rod knock for years with 20w60 weight in my younger days when I didn't have expertise to rebuild engine.
 

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Discussion Starter #6
I had an aircooled VW many years ago that had a bad connecting rod when I got it (saleman told me it was the exhaust)

I drove it to college for a year that way till it finally broke loss and smashed the piston into the head.

The thing I observed is I could hear it the best while holding a steady speed, or just slightly letting off the gas at a steady speed. I think the reason is that is when the piston is being pulled in both directions by the crankshaft with no real force on it - the expanded fuel is not pushing it down, and the compressed air is not holding it back on the exhaust stroke, so the bearing hits the rod at both the top and bottom of the strokes. Sounded like shaking a coffee can with a metal ball bearing in it.

You just adjusted the valves, where any of them tight? its possible you did not tighten the lock nut down on one of them and its coming loose, making the tappet noisy. But a tappet should sound the same all the time.

If it is a connecting rod you dont want to let it go for long, because the oil lubrication system depends on all the bearings being sound with the correct clearances. If you have one bad bearing the oil pressure will leak out thru that one, dropping the oil pressure for the entire engine, and soon all your other bearings will wear because the pressurize layer of oil between the bearing and the rotating surface is not as high as it should be.

On my VW the oil pressure light would flicker when the engine was hot and idling. I dont think there is a place to add an oil pressure sensor on the engine, or if a slightly knocking rod bearing would drop the pressure enough to notice, esp since you would have to know the idle speed oil pressure for a good engine with the same weight oil.

This might be a case where an experienced mechanic with trained ears needs to take the bike for a ride.
What weight of oil are you using. Did you go down on viscosity? Older engines with looser bearings will start to knock going from 20w50 to a 20w40. I nursed a rod knock for years with 20w60 weight in my younger days when I didn't have expertise to rebuild engine.
The previous owner has been using 10w40 so i've been doing the same. Temperature out here ranges from 23C (73F) to 35C(95F). Should i be running thicker oil? I know the first number is cold temp/starting temp, and the second number is running temp.
 

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The previous owner has been using 10w40 so i've been doing the same. Temperature out here ranges from 23C (73F) to 35C(95F). Should i be running thicker oil? I know the first number is cold temp/starting temp, and the second number is running temp.
At 95 degrees that's Houston temperature. I ran 20w50 year round on my 1100. You will get many different responses on oil weight, I'm just reporting what has worked for years in my bikes.
 

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Discussion Starter #9
Question: I just did the oil change 2 weeks ago (10w40). Can i just drain it, and leave the oil filter in there and just add 15w50? Or would i need to drain it and replace the filter as well?
 

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Question: I just did the oil change 2 weeks ago (10w40). Can i just drain it, and leave the oil filter in there and just add 15w50? Or would i need to drain it and replace the filter as well?
Manual says to change filter every other oil change (8000 miles). I would just drain and put in new oil.
 

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Knocking is also a symptom of using too high of an octane fuel.
I think you typed that backwards - hi compression engines need premium, or they will knock

running lean will make the engine knock, and premium will make a normal engine lean

it could also be the timing is not advancing correctly, that would make the engine balk, knock and generally run like crap.
 

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Discussion Starter #14
You know, i wonder how many others have this subtle knocking and don't know it cause of their loud exhaust....maybe i should change my stock exhaust so i don't hear any of these noises anymore hahah
 

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Discussion Starter #15
I think you typed that backwards - hi compression engines need premium, or they will knock

running lean will make the engine knock, and premium will make a normal engine lean

it could also be the timing is not advancing correctly, that would make the engine balk, knock and generally run like crap.
The bike was still feeling a bit off at 2 turns out on the mixture screws. Then i dialed it out another quater turn and noticed much improvement but started noticing the noise now that the bike is running smoother. I'm wonder if I turn the screws out another quarter turn (for a total of 2 and a half turns out), if it will help at all since it still might be a bit leanish?

My slender fingers are able to reach in and adjust the carb mixture screw without having to take the carbs out, using a flat heat bit.
 

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You know, i wonder how many others have this subtle knocking and don't know it cause of their loud exhaust....maybe i should change my stock exhaust so i don't hear any of these noises anymore hahah
I have cobra exhaust and turn the mp3 player up. I am old and 1/2 deaf anyway.
 

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Discussion Starter #17
Okay question: improper spark plug torque can lead to pre-ignition. I've never used a torque wrench for spark plugs so i just went finger tight, then a quarter turn. BUT there's a crush washer in there.. so everytime i take the plugs out to check them, and put them back in, the washer gets smaller and smaller, and the plug gets deeper and deeper.

My question is this: Do you use a torque wrench before the crush washer is crushed? Or do you tighten the plug past the crush washer resistance, and THEN use proper torque (Which in this case is 14.5 foot lbs)
 

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dont use any kind of lube or anti-seize on the spark pug threads

set the wrench to 14.5 ft-bs, tighten the plug till the wrench clicks and stop

if you have a beam type torque wrench stop when it gets to 14.5
 

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Discussion Starter #19
dont use any kind of lube or anti-seize on the spark pug threads

set the wrench to 14.5 ft-bs, tighten the plug till the wrench clicks and stop

if you have a beam type torque wrench stop when it gets to 14.5
So do i start the torque process before the crush washer is crushed? or do i tighten and crush the crush washer and then torque it to spec?

Again, keep in mind that the crush washer is thick enough to change how close/how far away the plug gap is. And if my engine is suffering from pre-ignition from the plug being too close, then it could be because i keep crushing the crush washer everytime i re-insert my plugs after checking them.
 

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So do i start the torque process before the crush washer is crushed? or do i tighten and crush the crush washer and then torque it to spec?

Again, keep in mind that the crush washer is thick enough to change how close/how far away the plug gap is. And if my engine is suffering from pre-ignition from the plug being too close, then it could be because i keep crushing the crush washer everytime i re-insert my plugs after checking them.
The small distance you are talking about will not make a difference, just torque to spec.
 
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