E: Engine Noisy Rocker Bearing

[Martyn Goodwin]

So my exhaust rocker bearing worked its way loose despite the use of the 'new' locking oil feed bolt. Result was lots of noise (I thought the bottom was falling out of the motor) and a 'flattening' of the top surface of the existing rocker bearing. See picture below

I see there is a ET26/6 described as an extra long rocker bearing - and I wonder if that is what I should use as a replacement.

Has anyone used these longer rocker bearings?

Will they help stabilise and quieten the rocker gear?

What is involved in fitting them?

 

[vibrac]

I would only regard the longer bearing as a temporary repair you must have a lot of wear in the tunnel book a session after the 2018 riding season

 

[Vincent Brake]

you have to -skim- machine the rocker tunnel Martyn, and use an oversise rockerbearing, either long or short, i do them with just 0,5 thou loose fit, by just bore them any just clean sise, and machine the bearing to fit.
Loose fit: so one and turn the fork of the arm straight over the valve colar, now and again it takes a file it the bolt hole to move the bolt either way!!!

one can also go the Argentinian way, hit a nail under it, (or a few)

 

[Bill Thomas]

So my exhaust rocker bearing worked its way loose despite the use of the 'new' locking oil feed bolt. Result was lots of noise (I thought the bottom was falling out of the motor) and a 'flattening' of the top surface of the existing rocker bearing. See picture below

I see there is a ET26/6 described as an extra long rocker bearing - and I wonder if that is what I should use as a replacement.

Has anyone used these logner rocker bearings?

Will they help stabilise and quieten the rocker gear?

What is involved in fitting them?

View attachment 20358

I think your problem might be something else, We have used the locking type for many years, With out trouble.
The long ones were not very good,
I put a bit on the Forum about having to take a lot of metal off the top of the rocker arm in two places, to allow the arm full movement after fitting the locking type.
How deep the valve seat is can alter how far things move.
Have you fitted Mk2 cams, And taken enough off the lower valve guide ?.
Good luck Bill.

 

[greg brillus]

Measure it against a new one, your one looks pretty worn. Has it left a deep ridge in the roof of the tunnel, if it's not too bad........... just fit a new bush.

 

[Martyn Goodwin]

I think your problem might be something else, We have used the locking type for many years, With out trouble.
The long ones were not very good,
I put a bit on the Forum about having to take a lot of metal off the top of the rocker arm in two places, to allow the arm full movement after fitting the locking type.
How deep the valve seat is can alter how far things move.
Have you fitted Mk2 cams, And taken enough off the lower valve guide ?.
Good luck Bill.

Hi Bill,

Std Mk1 cams, ET41/S locking 'O' ring seal lower guides, metal removed from rockers and clearance checked - but thinking about it - it was checked about 5,000 miles back and the 'noise' has only just started- Time to recheck the clearance?

When I looked 'in' yesterday the rocker bearing WAS loose with the locking bolt not secure - allowing quite a bit of slop - as evidenced by the flats worn on the top face of the rocker bearing.

rechecking rocker arm clearance in the morning - its almost 9pm here.

Martyn

 

[Martyn Goodwin]

Measure it against a new one, your one looks pretty worn. Has it left a deep ridge in the roof of the tunnel, if it's not too bad........... just fit a new bush.

Hi Greg,

yes a definite 'ridge' in the top of the tunnel. I am wondering/hoping that the longer rocker bearing will get it onto the unworn part of the tunnel. Any experience there??

Martyn

 

[greg brillus]

Pretty rare to find an original head that hasn't got a ridge there.........I found if the rocker bush measures up to original specs then they seem to work ok with the locking feedbolt mod, I generally fit new rocker pins as well as these seem to wear over time too. It is often the sideways play between the rocker and the inner sides of the alloy bush that causes an annoying "Tappet noise" as the geometry allows for this to happen. This seems to quieten the lot down and helps lessen the rattles, if that's possible.....................

 

[bmetcalf]

Maybe OT, but what do you use to press the pin out?

 

[Martyn Goodwin]

Pretty rare to find an original head that hasn't got a ridge there.........I found if the rocker bush measures up to original specs then they seem to work ok with the locking feedbolt mod, I generally fit new rocker pins as well as these seem to wear over time too. It is often the sideways play between the rocker and the inner sides of the alloy bush that causes an annoying "Tappet noise" as the geometry allows for this to happen. This seems to quieten the lot down and helps lessen the rattles, if that's possible.....................

The rocker pin is a finger press fit in the rocker itself. No tools were needed. So maybe a new pin as well??