so i think i have a bent valve spring?!

[Matt Chapter]

Exhaust valve, left side.  Video to follow, if I can capture it successfully and then post here...

The question is.. how bad is this?  Can it be driven?  Theoretically my R65 is my daily driver.  Is this something that can happen naturally, or is it a result of loose spark plugs, or maladjustment?  I just did the valves less than 100 miles ago.

[montmil]

A bent spring?

[Matt Chapter]

picture's worth a thousand words, so what's a video worth?  This might be worth a beverage, even though it's only 2 seconds long..

Note the disturbing lack of parallel spirals, and the grotesque movement..
http://www.flickr.com/photos/77662887@N05/8488287428/

How hard is it to take apart the valve train to replace that puppy?

[Matt Chapter]

should be public now...

It's hard to know who you want to see videos of your bent springs, if you catch my drift.

[donbmw]

You are not going to realy know until you remove the rocker arms. I have seen spring break  or get weak. There is more of a chance of a valve getting bent than a spring bending to me.

Don

[bruce_launceston]

I've only removed the valve collets and springs with the heads off. Normally you would use a valve spring compressor. I don't know if it can be done with the head still on, maybe with the piston at TDC and a couple of extra hands to compress the spring?

[georgesgiralt]

IMHO, could be a broken spring. The parts gets one on the other but when compressed, slip and then it look bent.
Repair asap as it will ruin the valve guide and the valve. I had this on my R65...
To remove without removing the head you need something to hold the valve in place. Basically, a spark plug without it's innards, which are replaced by a sturdy steel rod pressing the valve in place while you compress the spring to remove the locking tappets.
But IMHO, you'd better remove the head and do a proper valve job. the valve stem may already have suffered from this and, as these stems are not the strong point of the bike you risk a broken valve, piston, cylinder.... soon....

[Barry]

I can't see so well these days, there is something moving inside the outer coil. Maybe the spring is broken but is it also possible someone has fitted dual valve springs ?

[Matt Chapter]

I can't see so well these days, there is something moving inside the outer coil. Maybe the spring is broken but is it also possible someone has fitted dual valve springs ?

It's a classic case of "which of these valve springs does not look like the other".  The answer is that one!

If I have to take the head off to repair this, I'm in deep deep.. trouble.  I guess I'd better have a look at my Clymer manual..

[montmil]

Barry may be seeing things just fine... It does look, to me, as if there are dual springs fitted. Can you see if the other valve springs are duals? Something is going on within the outer spring coils...

"If I have to take the head off to repair this, I'm in deep deep.. trouble."

Even strain, Matt. Steady on. Most likely the head will need to be removed. It's not a difficult chore; the removal of the exhaust nut can be problematic should the threads be galled. If the nut refuses to turn smoothly, STOP! There's not much choice but to cut the nut off rather than destroy the threads on the head's exhaust stub.

[Matt Chapter]

Most likely the head will need to be removed.  

Arg.. so who wants to loan me a Tonquanockee cerimonial thingamajiger?

Ok, I'm making a shopping list.  Is there anything else I should think about doing, like pushrod seals, if I take the head off?  Should I just replace the valves no matter what, or inspect and then decide?

I drove it about 15 miles, max speed 65 mph in this state.  (Assuming that this is the cause of my poor engine performance)

[montmil]

First things first, Matt...

Do you have a rubber strap wrench? Cheap ones are at the Austin Harbor Freight.

Pushrod seals require removing the cylinder and piston as a unit; that's the easiest way, IMO. Also a full gasket and O-ring kit.

You may likely need a new head gasket for the head removal job.

New valves alone would not be a wise choice. Again, that's just my opinion. A complete head rebuild won't come cheap either. My advice is just what you said, "...or inspect and then decide."

Keep us posted and we can look over your shoulder as unpaid mechanic helpers. And that's the whole point of this forum, right?

Get on your bicycle or roll the cage but park your R65 for now.

[Bob_W]

Heads remove easily-six nuts. Exhaust nut wrenches should be easy to borrow if you not own one. Check with a local Airhead. A valve spring compressor should also be easy to either borrow or rent from an auto parts store.
Push rods seals do not require removing piston or cylinder, only the head. Rotate engine to TDC compression stroke on cylinder in question. Remove exhaust nut and header, carb, valve cover, six head nuts, carefully slide rocker arms off in one piece-do not let the needles fall out of the bearings, pull push rods,  remove head and then valve. Reverse going back together. Torque nuts in three stages up to about 25 ft lbs in sequence. Set the valves and ride.
New head gaskets are not that expensive. I would probably at least measure the other spring on that side while the head was off.
Doing this for the first time might take a couple of hours.
If in doubt check on a tech day locally. Airheads are the most helpful people I've ever met.
Bob

[montmil]

... Push rods seals do not require removing piston or cylinder, only the head. Bob

Gonna have to throw the BS flag on you, BobW.

To remove the old, leaky tube seals requires lifting the cylinder up off the crankcase. To gain the service space required, there's no other way to withdraw the pushrod tubes from the crankcase and R&R the seals.

And after the cylinder base gasket and a few O-rings have been disturbed, they, too, must be replaced or you'll run the risk of new leaks and have to do the job all over again. By pulling the cylinder up and away from the piston -just enough to expose the wrist pin for removal- the cylinder/piston unit can be removed for the necessary gasket and O-ring replacements without disturbing the piston rings.

Matt, Here's Snowbum's tips on the seal replacement: http://bmwmotorcycletech.info/pushrodseals.htm

[Matt Chapter]

Well, I swung by the $BMW$ shop today after work, ordered the spring, keeper, spring seat, and spring retainer.  47$.  I guess it could be worse.  Oh wait.. the parts won't be here for a week.

I've looked over snowbum's page, and my clymer manual... neither really covers removing the spring.  I guess looking at the fiche that the spring retainer is threaded somehow and holding the whole thing together?  I don't see anyway around removing the head, which means I should have ordered a head gasket.

I'm feeling a little better after looking over the procedure (and now that I have a boilermaker in progress..)

Can I disassemble now, and wait for the parts to arrive next week, or should I try to do it all at once?

Tool list: exhaust nut wrench.  What else do I need? (other than more beer!)