Help Diagnose Engine Noise - XR200

[ThumperCurtis]

Hey guys - I have a bud with a XR200 that is having some engine noise that he cannot identify. I'm posting the vid for him in hopes that the forum braintrust can help get the right diagnosis.

 

Notes:

He has adjusted the valves and the cam chain tensioner. 

I have asked him to confirm that oil is getting to the top of the valve head. 

 

Hopefully he can reply to this thread with more information.  

@XRepublic

 

Appreciate any and all input :-)

[XRepublic]

Looks like oil is getting to the top. I adjusted the valves twice... had a hard time finding top dead centre with both rocker arms having movement. Either way it still sounds like a lawnmower. Appreciate your input folks!

[joethumper]

1 hour ago, XRepublic said:

Looks like oil is getting to the top. I adjusted the valves twice... had a hard time finding top dead centre with both rocker arms having movement. Either way it still sounds like a lawnmower. Appreciate your input folks!

wish my xr200 sounded that good.....lol.....but anyhow, can you idle her down and then post a vid with her warmed up.....that would help i believe, hearing the noise when its slower running.....good luck

[XRepublic]

It's funny, she speeds up as she warms up...!

I thought the idle is a little fast. Not sure what speed it should idle at. But will try to slow it down and record. Thanks!

[XRepublic]

I just looked up two videos on YouTube of two different XR200's idling and they sound very similar to mine.......! Wtf?

[joethumper]

7 minutes ago, XRepublic said:

I just looked up two videos on YouTube of two different XR200's idling and they sound very similar to mine.......! Wtf?

with that noise too, that you think is wrong?

[Greenwrench]

I've seen the camshafts on those wear down the lobes and make similar valve train noise .

[XRepublic]

with that noise too, that you think is wrong?

Yes

[XRepublic]

I've seen the camshafts on those wear down the lobes and make similar valve train noise .

The top end was redone by the PO, new piston, rings, valves, cam chain - done by reputable shop, you'd think they'd check the condition of camshaft...?! Thanks

[chadzu]

Loosen the decompression cable at the head a bit and see if that helps.  If it is too tight the rocker will hit the decomp lever and make noise.

[ThumperCurtis]

1 hour ago, chadzu said:

Loosen the decompression cable at the head a bit and see if that helps.  If it is too tight the rocker will hit the decomp lever and make noise.

@chadzuThat was one of my thoughts as well. I say - disconnect the entire decompression mechanism to the top of the head and see if it gets any better. If my ears were hearing it right it sounded like it got louder as he moved to the right side with the decompression mechanism.   

[XRepublic]

Ok, I'll have to study that part and try that. Thanks!

[XRepublic]

wish my xr200 sounded that good.....lol.....but anyhow, can you idle her down and then post a vid with her warmed up.....that would help i believe, hearing the noise when its slower running.....good luck

Got a video of a slower idle that I'll ask Curtis to post as this app isn't letting me post, thanks!

[ThumperCurtis]

Here is another vide

 

[joethumper]

2 hours ago, ThumperCurtis said:

Here is another vide

 

im going to go out on a limb here....did you install the piston backwards? the arrow should of been pointed toward the rear of the bike......

 

[joethumper]

On 7/14/2017 at 6:54 AM, XRepublic said:

The top end was redone by the PO, new piston, rings, valves, cam chain - done by reputable shop, you'd think they'd check the condition of camshaft...?! Thanks

yes but how long ago? and is that what he told you before you bought the bike? could of been a fib

 

[joethumper]

is the timing right?

is the cam chain sprocket correctly aligned with top dead center?

is the cam chain tension adjuster working correctly?

is the correct spark plug used, sometimes a longer one is used and gets hit by the piston?

maybe a bent valve?

could be a number of things......did you try the decompressor idea yet?

good luck and let us know......you may need to tear apart the motor sometime down the road.....im in the process of rebuilding my top end and the guys here helped me out.....

 

[joethumper]

On 7/14/2017 at 6:54 AM, XRepublic said:

The top end was redone by the PO, new piston, rings, valves, cam chain - done by reputable shop, you'd think they'd check the condition of camshaft...?! Thanks

lol.....it took me a while to figure out what PO meant......previous owner?

[joethumper]

34 minutes ago, joethumper said:

im going to go out on a limb here....did you install the piston backwards? the arrow should of been pointed toward the rear of the bike......

 

on the piston there are 2 shallow cut outs on the top in a circular pattern......they are there for the valve clearance as they go up and down.....there is an intake valve and an exhaust valve.....one is bigger than the other so the cut outs on the top of the piston have to coincide with the valves diameter.....if the piston is installed wrong or backwards you got a bigger valve going into a small cut out which might be making the noise.....but i could be all wrong being that the piston would probably explode within seconds if installed wrong.......

[joethumper]

you have a fun bike there once that sound gets figured out.....hopefully the guys hear can help