Valve adjuster failure

[Gio]

After accelerating hard from some lights yesterday, the right side of the engine started to make a noise like the valve train has disintegrated. I limped home and this morning discovered the adjuster for the right side exhaust valve had come apart - the nut and half the threaded adjuster was found wedged in a channel, the other half of the adjuster was still in place. Push rod looks ok.

 

This (at ~47k km) is the second time the adjuster for this valve has failed (the first was at ~20k and replaced under warranty). I just did a valve adjustment. I use 4 thou inlet, 6 thou exhaust.

 

Anyone else had this experience? I wonder if Im over tightening the lock-nut on the adjuster?? Any other suggestions (apart from carrying a spare..)...?

 

Gio

[Mike Stewart]

After accelerating hard from some lights yesterday, the right side of the engine started to make a noise like the valve train has disintegrated. I limped home and this morning discovered the adjuster for the right side exhaust valve had come apart - the nut and half the threaded adjuster was found wedged in a channel, the other half of the adjuster was still in place. Push rod looks ok.

 

This (at ~47k km) is the second time the adjuster for this valve has failed (the first was at ~20k and replaced under warranty). I just did a valve adjustment. I use 4 thou inlet, 6 thou exhaust.

 

Anyone else had this experience? I wonder if Im over tightening the lock-nut on the adjuster?? Any other suggestions (apart from carrying a spare..)...?

 

Gio

53543[/snapback]

 

I have over 50,000 miles on various V1100 engines and I have not had any problems with the valve train. I usually run .008 intake and .010 exhaust. I can't see the failure happening if you over tighten the lock-nut.

 

Sorry ,

Mike

[edge]

Gio,

 

O/T: I tried responding to your board email but it was kicked back as a bad email address. Can you update or check your member data or contact me with another email accont so I can respond to your questions,

[big J]

Is the rocker arm drilled/tapped square to working axis? Is the machined face where the locknut tightens square to threaded adjuster bore?

[Guest Nogbad]

Is the rocker arm drilled/tapped square to working axis? Is the machined face where the locknut tightens square to threaded adjuster bore?

53562[/snapback]

 

These are good questions. If the hole is tapped out of square a bending load will be applied to the adjuster when the nut is tightened and this could account for the failure.

 

I would swap the offending rocker arm as well as installing a new adjuster. Overtightening could conceivably overload the threads, but I think you would have to go pretty hard on it.

[Guest ratchethack]

Gio, I believe this might be a first part failure of it's kind, at least on this forum. I'm with Nogbad re: his suggestion to replace the rocker arm. I'd reason it this way: If the threads inside the adjuster shaft bore of the rocker were machined far enough out of mfg. tolerance (too loose), this would provide an opportunity for the threaded adjuster shaft to flex a little with every valve opening. This flexion could weaken the adjuster shaft to the point of failure over time. A flaw or void in the forging at the periphery of the bore where you can't easily see it would also be a possibility that would allow the shaft to flex in use. In any case, since this has happened twice now, I'd say there's a high probability that the problem is with the rocker.

 

Another thought not likely related to your particular situation, but to the discussion: In case of overtightenting of the adjuster nut, I'd assume that since the rockers are forged, and that they also have more threads than the adjuster nut (can't remember for certain, but I believe this is true), that the nut, if over-tightened, would always be the point of failure - not the rocker.

 

Good luck!

[Gio]

Good suggestions - thanks. I'll take a closer look at that rocker arm and also replace with a new one (reasonable price and funds permitting...)

 

Cheers,

 

Gio

[Gio]

Gio,

 

O/T:  I tried responding to your board email but it was kicked back as a bad email address.  Can you update or check your member data or contact me with another email accont so I can respond to your questions,

53546[/snapback]

 

Hi edge - just sent you a pm.

[Gio]

Good suggestions - thanks. I'll take a closer look at that rocker arm and also replace with a new one (reasonable price and funds permitting...)

 

Cheers,

 

Gio

53575[/snapback]

 

Relative to the rocker arm, as far as I can tell the adjuster nut makes even contact and there is no evidence of any mis-alignment.

 

A new rocker arm is ~ $220 CDN and not stocked at my dealer so I'll see how the new adjuster holds up in the interim.

[Georges]

After accelerating hard from some lights yesterday, the right side of the engine started to make a noise like the valve train has disintegrated. I limped home and this morning discovered the adjuster for the right side exhaust valve had come apart - the nut and half the threaded adjuster was found wedged in a channel, the other half of the adjuster was still in place. Push rod looks ok.

 

This (at ~47k km) is the second time the adjuster for this valve has failed (the first was at ~20k and replaced under warranty). I just did a valve adjustment. I use 4 thou inlet, 6 thou exhaust.

 

Anyone else had this experience? I wonder if Im over tightening the lock-nut on the adjuster?? Any other suggestions (apart from carrying a spare..)...?

 

Gio

 

I'm having the same problem on my V11 lemans.

I sent back the bike to the dealer. He replaced the adjuster, telling me that the last time I had adjusted the valves, I had over-tightened the locknut.

 

So, I got back the bike, and about one week later, I pushed my bike above 7000 rpm, and it happened again.

 

Back again to the dealer. He replaced the nut and pushed the engine over 7000 rpm: same problem again.

So now, each time the engine is turning above 7000 rpm, one or two adjuster are failing.

 

My dealer told me that it's the first time he experience that problem, so he is planning to get some help from the factory to find a solution.

 

I let you know about it, as soon as I have some news.