06 TE 450, Valve Shim Popped, Why?

[tennessee thumper]

Update on the previous thread.

Turns out the right intake valve spit out the shim, quite odd indeed. So I am wondering if anyone has had this happen or has experienced any issues with valve seating, resession or springs in 06 engines. It seems something like this may have happened, causing the shim to pop out and land in the bucket.

New shim went in about 4 months ago and the bike has been running perfectly. Easy start and idle, no smoke, great throttle response and good performance ever when hot. This seemed to have happened all of a sudden.

I've got more dectective work to do thanks to some helpful advise from Up[Tite. Anyone have comments or thoughts, my ears, eyes are open.

[Ruffus]

Any chance the valve spring broke? Loss of sufficient pressure & shim goes boing?? Just a wild guess off the top of my head

[Nielly]

I recall reading a post like this many many moons ago, but I don't think it was ever really resolved just a lot of speculation about the use of the manual decompressor when starting. But then I think the decrompressor works the right exhaust valve not the intake? Your recent work in that area, although routine might point to something. Out of spec shim perhaps?

[Some Dude]

Sounds like you have a sticking valve, just experienced a very similar issue after a bike sat for 2 months and was run with race gas before being put up in storage. Race fuel caused some corrosion on the valve seats and make both exh valves stick bad.

[tennessee thumper]

Thanks for all the input here...I've heard that leaving the bike sitting and/or using lousy gas can cause a valve to stick. I've been riding the bike on a daily basis so that can be ruled out. I'm in central Arkansas and burn only 93 rated gas, but no telling if there is something in the fuel that may have caused this.

As far as shim replacement goes, I put new ones in about 3 months ago, around 1000 miles. After the shim replacement the bike was running like a champ, no choke needed on start up and was idiling perfect when cold and when hot after a long ride. I'm not ruling out user error at all, there is always a good possibility home mechanic error is to blame but I am having a hard time pointing the finger at myself here since this happend so suddenly and with out warning...

[glangston]

What sort of damage to the engine, if any? You asked the right guy for advice. Good luck.

[tennessee thumper]

I shut the bike down as soon as I heard metal rolling around, so there was minimal damage, if any at all.

Initial inspection shows things to be fine inside the "bucket". When the engine first started missing and I heard metal on metal, I assumed the worst.

I'm hoping, in a odd way, someone else has had a sticky valve so I know what went wrong and what may have caused the shim to pop out like it did.

This may also just be an anomoly or one off event.

The forum is doing it's job wonderfully, keep the comments coming.

TT

[Dave Hopkins]

There was another one did that maybe a year ago. It can only happen via way of the valve not closing as fast as the cam was allowing it to (called valve float) and its very hard on parts! This can happen one of two ways;

1: It was over reved (at least "over" from the valve springs point of view) so the valve was not closing as fast as the cam allowed, or

2: It was sticking, this can happen from gummy gas or corosion as Bobby from Atlanta described or it can be a valve stem got too hot and tried to weld itself to the valve guide. This is usually a lean spot in the carb and is what I think you need to dwell on.

Off road throttle use varys from lots of crawling along idle thru 1/8 throttle and an occasional whacky, then maybe get out in the open and give it a big adreniline blast of wide open.

On road there is a lot of situations where you go say 1/4 throttle for miniutes! Maybe higher up? Any lean spot in the needle taper here will reflect back to the engine and superheat nice pieces like your Ti valves.

So what needle (5 letter code), clip position & main jet do you have? I bet the 3rd letter on the needle is a "D", they are deadly lean from 1/4 on up

[tennessee thumper]

Dave, nice post and explaination. Needle, clip and jet are all stock. I did recently adjust the fuel screw so it may be running lean. Riding at high rpm for long periods has not been a problem at all.

[wang]

It might be a good idea to perform a leakdown test..and or look at the piston top to determine if there was any piston to valve contact...which is possible when a valve sticks enough for it to have spat out a shim

Even a valve with a very slight bend will still run fine and even have normal compression....but the valve head will eventually break off with dire consequenses

sticky valves can be remedied with penetrating oil applied through the exhaust or intake port

seems strange...usually its the exhaust valves that stick...hmmm

check your springs too....

[tennessee thumper]

UPDATE on this thread:

Filed down the shims to spec, oiled valves and have 500 miles since the incident. Still not sure what happened. I've made sure to use Shell gas and none of the chepo stuff that seems to be everywhere in Central Arkansas.

Okay...see ya.