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Message started by roddy on 02/12/25 at 17:38:33

Title: engine noise
Post by roddy on 02/12/25 at 17:38:33

from az to all. i have a 2012 with 24k miles. i bought it with 5k miles and treated her like a fine old mare. i just changed the oil {not from 5ooo miles} pulled the tank checked the spark plug. the plug was just barely tighter than hand tight. after all that, started it up and when i snap the throttle there is a noise as if a rod bearing or wrist was going out. any ideas? runs really good though. thanks for all your info.

Title: Re: engine noise
Post by Dave on 02/13/25 at 02:38:13

The obvious question is - have you ever checked your cam chain tensioner?

http://suzukisavage.com/cgi-bin/YaBB.pl?board=tech;action=display;num=1176999168

Title: Re: engine noise
Post by Ruttly on 02/13/25 at 07:41:59

Did you put filter in backwards ?

Title: Re: engine noise
Post by DragBikeMike on 02/13/25 at 15:53:17

Roddy, please clarify.

Your engine was running fine prior to your recent oil change and spark plug check. No unusual noise. You changed the oil and checked your spark plug. To facilitate spark plug removal you removed your fuel tank. After the oil change and plug check, you started it up and it now makes a loud knocking noise, similar to a rod knock. Do I have that correct?

Did you do anything else? Did you change the oil filter? Did you install a new/different spark plug? Did you adjust valves? Did you rotate the engine with a wrench (like on the alternator rotor bolt)? Did you remove clutch cover or alternator cover?

Title: Re: engine noise
Post by roddy on 02/13/25 at 17:57:38

18232E3928243F39222A27384B0 wrote:

The obvious question is - have you ever checked your cam chain tensioner?

http://suzukisavage.com/cgi-bin/YaBB.pl?board=tech;action=display;num=1176999168

yes. i have the extended one put it in at 20k. thanks for reply

Title: Re: engine noise
Post by roddy on 02/13/25 at 17:59:29

46616060786D140 wrote:

Did you put filter in backwards ?

no. i have installed the filters many times but thanks for the reply

Title: Re: engine noise
Post by roddy on 02/13/25 at 18:02:58

60666915171014240 wrote:

Title: Re: engine noise
Post by DragBikeMike on 02/14/25 at 13:25:46

"yes. changed filter checked valves only. same spark plug. did not remove cover or turn engine. thanks for replying. checked to see if flywheel was loose....not "

You say you checked the valves but you did not turn the engine. How did you position the engine at TDC compression without turning the engine? By "checked valves only" do you mean that you only verified clearance with a feeler gage and did not do any sort of adjustment? Did you try to adjust the valves and if so are you sure you did that adjustment with the engine at TDC on the compression stroke?

You state that you checked to see if the flywheel was loose. How exactly did you do that? Is it possible that you checked the alternator rotor bolt and thought that it was the flywheel. The alternator rotor is secured with a bolt while the flywheel is secured with a very large nut. To get to the flywheel nut you have to remove the alternator rotor and the starter clutch gear.

This is the alternator rotor bolt. Is this what you checked to verify it is tight? If so, you checked the wrong fastener.

Title: Re: engine noise
Post by DragBikeMike on 02/14/25 at 13:35:30

This is the flywheel nut. As previously mentioned, you have to remove the alternator rotor and starter clutch gear to access this nut. It is BIG torque and you need a flywheel holding tool and special socket in order to tighten the nut properly. It has a special Belleville washer behind the nut, and that washer keeps a good deal of tension on the nut even when the nut is loose. You can't just put a wrench on it to verify that it is tight enough. You have to hold the flywheel with the special tool and tighten the nut to 115 ft-lbs. You need a special deep socket.

Title: Re: engine noise
Post by DragBikeMike on 02/14/25 at 13:41:18

This is a video of the sort of noise you can expect from a loose flywheel. When I opened it up to check, my first impression was that the flywheel nut was tight. I couldn't rotate the nut with a wrench, but when I installed the flywheel holder and hit it up with a socket and torque wrench the nut rotated a whole bunch. After I properly tightened the nut, the noise was gone. Note how the knocking noise is most prominent when I snap the throttle. It really sounds like a rod knock.

https://www.youtube.com/shorts/KUhN_OHQhmo

Title: Re: engine noise
Post by DragBikeMike on 02/14/25 at 13:48:17

This is a video of piston slap. I seized this piston climbing a six-mile long 6% grade into a 40-mph headwind. I had the piston clearance set too tight and the old girl just couldn't take any more. The piston slap noise differs from the loose flywheel noise. The loose flywheel is most prominent when you throttle up while the piston slap is most prominent at idle. I don't suspect you have piston slap, but the vids should give an idea of what the two failures sound like (similar but not equal).

https://www.youtube.com/watch?v=Lyt0CWKLCJY

Title: Re: engine noise
Post by roddy on 03/24/25 at 19:19:01

hi all. i got the rotor puller today!!! tomorrow i will attempt to check the flywheel nut for tightness. hope for the best thanks to all who responded to my post

Title: Re: engine noise
Post by Gary_in_NJ on 03/25/25 at 06:55:05

Seems like everyone is diving down the rabbit hole here.

Before the spring maintenance there was no noise, right? After a service there is a noise, right?

The solution here is not to investigate NEW things, but to review what you did. I would go back and retrace your steps before digging into things not associated with the recent maintenance. I've seen it happen too many times...damaging something unrelated to the problem because you've convinced yourself it must be the problem.

My thought - if you checked the valves did you mess with the decomp lever? Is is possible that its vibrating and what you hear is it slapping back and forth? Look for the simple solutions before you start pulling parts off the engine.

Title: Re: engine noise
Post by ThumperPaul on 03/25/25 at 07:37:14

5852565C575E5A530D0B0F3F0 wrote:

Seems like everyone is diving down the rabbit hole here.

Before the spring maintenance there was no noise, right? After a service there is a noise, right?

My thought - if you checked the valves did you mess with the decomp lever? Is is possible that its vibrating and what you hear is it slapping back and forth? Look for the simple solutions before you start pulling parts off the engine.

Great points, Gary! I’ve had the decomp make a heck of a lot of racket and I thought the worst. Adjust the decomp and it went away like magic.