650L Top End Ticking w/ Video

[FrankenWompus]

Hey All,

 

My 650L has just had a top end put in it. I had a valve job done while doing it as well. Now it's got quite a tick coming from the top end now that's got me worried.

 

Here's a video.

 

https://youtu.be/2Xk8pW4l5ZY

 

What I didn't show in the video is that it is the same no matter what the RPM.

 

I primed the oil pump, so I know there's oil getting up there. All the valves have been triple checked to be within spec. The Auto Decompress makes a really loud tick when I crank it by hand, but that should go away when it's on idle, right?

 

There is a quieter tick when the exhaust is on it's way closed again, which could be the culprit. It's the first 'tick' in this video.

 

https://youtu.be/1WTE4s53r_8

 

Please help me out. After putting a whole top end in this thing, taking the valve cover off again is the last thing I want to do, but I'm afraid that I may have to. I'm ready to take 'er into a shop and pay someone else to look at it...

 

Thanks in advance!

 

[bork]

In 1st video, sounds like an exhaust leak, but on the pc, its hard to tell.

[XR650L_Dave]

If the tick is valvetrain (or exhaust) related, it will change cadence 1/2 as much as the engine rpm changes, so it can seem like it doesn't change much with RPM.

 

I'd carefully 'sniff' around with a piece of rod pushed into your thumb with your thumb in your ear and hunt for the source a bit.

[JoeRC51]

If the tick is valvetrain (or exhaust) related, it will change cadence 1/2 as much as the engine rpm changes, so it can seem like it doesn't change much with RPM.

 

I'd carefully 'sniff' around with a piece of rod pushed into your thumb with your thumb in your ear and hunt for the source a bit.

 

Screwdriver with the handle against your ear.

[brianhare]

or you could get a stethoscope for a whole 5 bucks..lol

 

 

B

[bork]

_{Also a 1/2" id x3' long rubber or vinyl hose to the ear is another helper, besides the metal to engine & ear.}

[Guymon dude]

Does the tick go away one the engine is warmed up?

[FrankenWompus]

It does not go away when it's warmed up. Today's the day I'll be checking it out, so I'll update soon.

[Dirtymutt9]

a buddy of mine had a heavy tick like that on an xr600r. I turned out to be the decomp mechanism on the cam. Im pretty sure the 650l head is 95% the same as the 600r head

[FrankenWompus]

Well kids, make sure that you tighten your cam sprocket bolts!

 

What was difficult to tell in the videos is that both exhaust valves would tick and move at the same time. It was almost like the cam was getting caught on something and letting loose when the pressure was enough, causing the valves to tick. I figured the likelihood of both of the rockers ticking at exactly the same time was miniscule if it was the rockers themselves, so it had to be related to the cam somehow.

 

I looked at the cam as best I could with the valve adjuster covers off and a flashlight but I couldn't see any debris on the cam lobes.

 

I decided I'd have to take the valve cover off.... and when I got in there...

 

 

Whoops!

 

There was definite scoring on the side of the bolt as well.

 

 

They had been ordered brand new for this because the guy before me had put some crappy ones in there, so that was my smoking gun. I must have been so excited to get my timing right that I just moved on to whatever was next instead of tightening them down. Labor intensive lesson learned, but I'm glad I dug around and found it.

 

I snugged them up and put it all back together. Lo and behold, no ticking!

 

I hope someone else never has this problem, but I thought I'd put this out there for posterity should anyone else have a similar tick.

 

In my original post I said that the ticking was the same no matter the RPM, but that wasn't true. The ticking got faster w higher RPM and slower with lower RPM. It ticked 'at the same rate as' the RPM if that makes any sense. Sorry for the confusion!

 

I'm not sure how to edit my original post, otherwise I would.

 

So to recap, the first tick in the second video I posted was the tick that was causing the issue (the second tick in the video was the auto-decompress and that one is normal). It was due to me not tightening the bolts on the cam sprocket and them hitting something on the way around, causing the valves to stay slightly open and then releasing when there was enough pressure, causing a tick.

Edited August 29, 2016 by FrankenWompus

[brianhare]

Someone on ADVrider nuked his topend due to that......AND...the manual calls for thread locker,,,,,,,did you use threadlocker this time????????????????

 

B

[mcma111]

No thread lock. I just tighten the piss out of them...

[FrankenWompus]

I did not put thread locker on, but I did tighten the piss out of them. ?