[08 KTM 450] Clattering from engine, can't figure it out. Please help!

[rudolfs001]

The bike used to run fine, then this clattering slowly started getting louder and louder until it died and I had to push it back home. I don't recall any events happening that would have caused this, though it was right after I moved from Colorado to California (carbs were jetted for Colorado).

Two years later, I've made sure the valves are in spec, replaced the cam chain tensioner with a manual tensioner and made sure the cam chain didn't skip any teeth, replaced air filter, spark plug, cleaned the carb, rejetted carbs for sea level.

It runs, but still with the clatter, so I haven't ran it more than a minute or so. I can't figure it out :mad

Here's a video of the sound:
https://www.youtube.com/watch?v=RfPzp6uAbbk

Any ideas appreciated!!

 

[augustiron]

That sounds nasty. Does it change with the clutch in or out?
I am more familiar with the rfs engine, but things to think about
- valve clearance (duh)
- broken valve spring
- cam bearings
- cam chain tensioner
- primary nut and woodruff key (I replace these on any rfs I buy)
- rod bearings
- clutch assembly

I'd take the valve cover off and check everything under there I can. Then the clutch and primary side, then the stator side.
If you don't find anything there, off with the head, and keep digging till you find it.

Also, you are not alone
https://youtu.be/KipHrQ4XsEg

 

[OaklandF4i]

Augustiron is spot on. More digging required, tough to impossible to diagnose via the Internet. I'm not that familiar KTMs, but torn down my share of thumpers.

Personally it sounds much deeper than a simple valve tick and more like a clank/knock. If it were my bike, I wouldn't be running it anymore for any extended period until I started tearing it down. Epescially if it already died once when the noise increased. You could possibly only be making your repair more expensive.

Look for the stuff already mentioned and if nothing is obvious, time to tear down or take it to some one who can. Good luck :thumbup

Edit: it may be helpful for you diagnosing to put a long and large screw driver to your motor with your ear on the other end. Move around until you determine where the noise is loudest. It sounds corny, but it does help pinpoint it.

 

[rudolfs001]

Thanks!!

When I'm checking things, what am I looking for other than the obvious "bits are in pieces that shouldn't be"?

I've never gone into the engine of a bike.

If it is a bad bearing, what does that look like? is it just that the connection is loose and jiggling?

 

[Busy Little Shop]

To troubleshoot an internal noise the first step is to establish the
rate at which it occurs... is the noise in time with the camshaft or
crankshaft??? camshafts rotate 1/2 the speed of the crankshaft...
possible source of camshaft speed noises are shim and bucket
clearances... loose cam bearing blocks... broken valve springs...
possible source of crankshaft speed noises are a scuffed piston...
stuck piston ring... rod bearings...

To pin point the exact location of the noise hold a long tip screw driver or a
length of garden hose up to your ear and probe the suspected area...

 

[planegray]

use a paint filter to drain the engine oil through, see if you catch any parts

 

[mototireguy]

use a paint filter to drain the engine oil through, see if you catch any parts

+1

The ratio of metal bits in the oil dump can help suggest how ok/bad things are and how you might proceed.

 

[augustiron]

Do you have a safe place to tear into an engine and have Hundreds of parts lying around for a while?
Are you organized enough to bag and tag, take.photos and use a manual to understand what you are doing?
Do you have a killer tool set and.lots of time?
Are you ready to walk away and eat the loss of your current investment and added time if the cost of repairs is more than you should spend?
Are you curious, good with tools?

If yes to all these, dig in. If not, you are setting up for failure.

 

[augustiron]

I understand looking at the oil, but *something* is way wrong in there. Steel or aluminum, you have several components of either metal to suspect. You will be opening it up to find it.
Look for.obvious stuff, loose stuff, etc. It should be fairly obvious when you get eyes on it, but it could be deep inside.

 

[OaklandF4i]

Thanks!!

When I'm checking things, what am I looking for other than the obvious "bits are in pieces that shouldn't be"?

I've never gone into the engine of a bike.

If it is a bad bearing, what does that look like? is it just that the connection is loose and jiggling?

Basically yes. Sometimes you will find an obvious source with a loose or broken component. Sometimes its less obvious when a part looks good but beyond its service limits. Sometimes its a combination of things. And sometimes.... its a head scratcher and you have to make an educated guess. :laughing

Things like rods have free play tolerances specified in service manual as an example. If its of interest, you have the time, space, money to invest in tools, patience, and will to learn.... its possible to do yourself. Everyone that wasnt professionally trained committed to jumping in to the unknown to learn once. Expect to make mistakes that cost money, part of the learning process. Doing it yourself isnt cheap, its just cheaper and sometimes not all (learning mistakes.)