1100 noisy top end - pushrods?

[MattW]

My 1100 has developed a recurring problem with its valve clearances on the right hand cylinder head.

This started after a high speed 400 mile autobahn thrash last September on the way to a tour around the alps. Ater this 'thrash' it developed a very 'tappety' noise from the right hand cylinder. After a bout of 'worry' at the time, I decided to leave it be and see if it got any worse (or indeed died a horrible death), with my fall back option being ADAC recovery. As it was, it didn't get any worse and we completed our two week trip with no further problems.

When I got home, I checked the valve clearances and discovered that the right hand inlet and exhaust clearances had opened up by about 0.05mm. I removed the head and cam carrier - the cam and followers looked perfect - no obvious wear and the cam bearing was smooth and without play, rocker and shaft had no play. I also tried to tweak the pushrod buttons to see if they were loose - couldn't make them move.

So I bolted it all back together, reset the valve clearances and it all appeared fine...

Until this weekend where I've just done couple of hundred mile trip.

I've now got a noisy right hand head again - subjectively not as noisy as the last time but it sounds like the valve clearances have opened up again. Performance, fuel consumption seem unaffected, it's just gone noisy...

The only thing I can think is that the pushrods have the 'issue' that Steptoe has posted about previously. Can these still be bought - none of the usual parts suppliers list them?

Any other ideas would be greatfully received.

 

[Trullion]

I guess you've seen the Chris Harris video on YouTube about this. I would have thought it's unlikely that all four pushrods would develop the fault at the same time (but what would I know?). Another possibility is that the case hardening has worn through on the adjusters. I say this because on my 1100 a few years ago I stupidly used the wrong torque when tightening a valve adjuster (I didn't usually bother using a troque wrench for this, and haven't since, having reverted to doing it by feel). Anyway, I ordered a couple of used ones from Motorworks. When they came I found that one of them was quite scuffed on the foot i.e. where is bears against the valve stem. I guess you'll need to have a look. Sorry I can't be of more help.

 

[MattW]

I guess you've seen the Chris Harris video on YouTube about this. I would have thought it's unlikely that all four pushrods would develop the fault at the same time (but what would I know?). Another possibility is that the case hardening has worn through on the adjusters. I say this because on my 1100 a few years ago I stupidly used the wrong torque when tightening a valve adjuster (I didn't usually bother using a troque wrench for this, and haven't since, having reverted to doing it by feel). Anyway, I ordered a couple of used ones from Motorworks. When they came I found that one of them was quite scuffed on the foot i.e. where is bears against the valve stem. I guess you'll need to have a look. Sorry I can't be of more help.

Thanks for the reply.

It's only one head (right hand), so only two pushrods, but you're right - it would seem unlikely for multiple pushrods to develop the same fault. I've not managed to raise the enthusiasm to pull the head cover yet but when I do, I'll check out the adjusters - hadn't thought of that possibility.

 

[MikeO]

Have a look at this thread Matt - Fast Forward to post 15...

Mike

 

[MattW]

Have a look at this thread Matt - Fast Forward to post 15...

Mike

Thanks Mike but I had my right hand head completely to bits last time this happened and the cams, followers etc were immaculate. The noise is definitely tappety rather than a knocking - the clearances seem to be opening up - resetting the clearances last time this happened cured it briefly but it's happened again...

 

[Antti]

Valve seats moving when engine gets hot and stressed? That would mess up the valve clearance.

 

[MikeO]

Thanks Mike but I had my right hand head completely to bits last time this happened and the cams, followers etc were immaculate. The noise is definitely tappety rather than a knocking - the clearances seem to be opening up - resetting the clearances last time this happened cured it briefly but it's happened again...

I'm confused by ALL the clearances opening.

The tappet lock nut is very low torque and would be easy to strip. It might be that a couple of the threads are damaged and they are opening after some time? I'm not sure what the cost of a new adjuster and nut would be, but it might be worth a look.

Clearly your first stop will be to check the clearances and see which (if any) have changed.

Please update the thread when you do - it has me intrigued...

 

[MattW]

Clearly your first stop will be to check the clearances and see which (if any) have changed.

Please update the thread when you do - it has me intrigued...

Will do Mike - I'll probably pull the rocker cover this weekend and have a poke around...