Valve Spec Discrepancy and Engine Ticking

[ayjay1975]

I have a 2006 200GY-5. It seems there is a discrepancy between the manuals specs, and the sticker on the bike’s specs for valve clearances.

The sticker on the bike says .03- .05mm or .0012”-.0020”

The manual says .05mm for both.

My engine sounds fantastic cold. Once hot, it sounds like a sewing machine, but also seems to have a pronounced tick. My buddy has the same model and his engine sounds a lot less clicky hot. I have adjusted my valves and had varying results, bust basically the tick always returns when hot. I have also tried changing the oil with 30 weight, 10/30, 10/40, and 20/50. It seems quietest with 20/50. Straight 30 weight was the worst. I understand that too tight of valve adjustment can be tough on the valve seats, is it possible there is a lifter failing? Do these pushrod engines even have lifters? (I have not seen an engine diagram) This clicking is making me nuts. It’s actually embarrassing. Any discussion appreciated.

[ob1]

A certain amount of ticking is needed. If there is no ticking, a valve may be being held slightly open, which will destroy the valve seat.

The engine has pushrods that ride on a cam on the crankshaft.

When you checked the valve lash, was the engine at TDC and the rocker held tight to the pushrod?

Have you checked that the rocker assy is tight to the head? Does your bike have the EGR/ smog equipment? The EGR outlet on the head could be leaking. The exhaust header could be leaking, either of which could be mistaken for excess valve lash.

[Savage]

Drill out your muffler with a 3/4" hole and the ticking goes away... kinda

[molypod]

Originally Posted by Savage

Drill out your muffler with a 3/4" hole and the ticking goes away... kinda

Yah way...
made mine sound like a hotrod sewing machine

ticktocktock now instead of tickticktick

[Savage]

Mine's more thump thump thump.
Sounds like a chopper is flying overhead when its idling.
Love it!

[liverchip]

Yes the pushrod motor has lifters(tappets) which serve to transfer motion from the camshaft to the pushrod. These are solid lifters(tappets) and not hydraulic, thus explaining the need for the valve train clearance. As for the excessive ticking or clicking. I have the same bike and have adjusted my clearance to .05 to days ago with fantastic results. My valves were a bit loose when I first checked them.....about .07-.08mm...the difference to the ear was extremely noticeable. As to why it sounds louder when hot, not sure...perhaps oil pressure is dropping off and you're hearing something else. There is a bit if play on the rocker shaft along its pivot, which can be rather loud in combination with loose valves can sound horrid( it did on my bike anyway)

[red2003]

Liverchip, the pushrod motor doesn't have what you would consider tappets. The cam transfers its motion through two L-shaped cantilever levers which move the pushrods up and down. Check out the cam diagram here:

http://pioneermotorsusa.com/download...50GY_200GY.pdf

[liverchip]

Ok I sand corrected....My point was that the pushrod does not ride directly on the camshaft. In my opinion it is still a lifter, although not a tappet.

[frostbite]

In my opinion it is still a lifter, although not a tappet. :Wink:

Oh, you mean a 'rocker arm'

[liverchip]

No, the rocker transfers the motion to the valve from the pushrod. The lifter transforms the rotary motion of the cam lob into the lifting motion used by the pushrod to actuate the rocker thus opening the valve. Bear in mind this is only the case in a pushrod motor, not an overhead cam motor. In am overhead cam motor the rocker runs directly off of the cam, or at least in the case of my car it does anyway.

[ayjay1975]

Thanks for all the responses!

I do not believe the bike has any smog equipment.

Low oil pressure is something that had crossed my mind, BUT if the machine doesn’t have hydraulic lifters, why would this cause the tick? Maybe something else is sloppy and cold thick oil dampens the nose? Can I connect a gauge to the port on the head to get an oil pressure reading? Sure seems like it is comming from the head.

I checked, and my exhaust pipe is nice and tight to the head, and does not appear to be leaking or hace signs of carbon blow by.

I have had DOZENS of bikes over the years, including an old xr75 that is pushrod also, but none sound this ticky. I am concerned I have a mechanical part way out of adjustment or failing.

I pulled my valve cover off again tonight, and it looks like I have my lash set a little to tight. (That should mean it would be LESS clicky) I will set it to spec this week and see how it behaves. I am sure it will still tick. I double checked to be sure I was at tdb by pulling the plug when I checked, as well as lining up the timing marks. I buess if I was 360 off, one of the valves would be clearly open, correct?

Appreciate engine diagram, it really helped make things clear for me for the valve train works. I had assumed it had some sort of hydraulic tappet and had HOPED it might “pump up“ over time. I am shocked at the difference between the nose level cold vs hot. Cold it sounds like a Honda, hot, sounds like junk. Seriously, worries me.

Again, appreciate the disucssion.

[liverchip]

Hmmm...the change in sound is really puzzling...Did you happen to check for excessive linear play along the rocker fulcrum? In other words, if you grab a rocker and push it side to side, across the head, does it move or make noise?

[ayjay1975]

Yes, I di notice that he exhaust rocker did have more side to side play than the intake side, but didnt see a way to adjust for that short of closing the gap with a hammer!

[liverchip]

Normally you can't without adding shims. If you move it do you hear the clack sound?...If you hear any noise, that might be it. The rocker axis on my bike is terminated using a welded nut, thus it cannot be removed for adding shims.

[ayjay1975]

Let's assume your right, and I suspect you may be... are shims available? Should I be concerned, or forget about it? Still dont understand why is gets worse with heat though. YOu would think that as things expanded, the clearances would tighten up, not loosen. I also wonder about todays multiviscosity oils... maybe I shoulde use straight 40 wieght or something...