What options for identifying a loud tic in left cylinder

[malmac]

Well I have not had the R75/6 very long and most of that time I have been away from home.

So back home, connect the battery and fire the bike up.
Loud ticking in left cylinder - only a very faint tic in right cylinder.
So I adjusted the end float on the rocker arms and set clearances .2mm and .15mm.
Start her up and most of the tic is still there in the left cylinder......mmmmmm
There was too much end float, so I thought she would be good following adjustment.

I will take her out for run tomorrow to see how that noise changes when she gets hot.
The bike has done 100,000km and as far as I know is still on first set of pistons.

Any ideas????

I know some of you enjoy seeing any custom tools. So here is my tool for adjusting end float on rocker arms.

[schrader7032]

Potentially the head gasket is oriented wrong. If that's the case, the pushrod could be rubbing on the edge of the gasket as it moves up and down.

Maybe the needle bearings for the rocker arm are slowly failing.

[malmac]

Kurt

Thank you for the ideas.

If I pull the pushrods out I will be able to determine the rubbing issue.

Needle roller bearings is a possibility.

Do you have to replace the complete rocker arm assembly or can the bearings and shaft be replaced?
I need to do some homework.


Regards


Mal

[schrader7032]

The needle bearings can be replaced separately, although they're pretty expensive. Oak Okleshen wrote about how the inner collar of the rocker housing can break off and the bearings can migrate out...this is usually visually seen with bearings found inside the valve cover or in the oil pan. Likely if the collar is intact, then maybe these bearings are not an issue. Oak warned that there are two slightly different size needle bearings which can't be mixed up...and there's a specific number of bearings installed of each type...part number 11-33-1-261-712, four per side. There are either 30 or 31 bearings depending on the supplier.

[malmac]

Thank you for the heads up on the different bearings.

Started the bike and was going for a ride and I had a short somewhere, so no ride today.
Now I have to find the problem before I can get back to the engine noise.
and this is a bike in good condition, yes but it does have the years tucked under it's belt.

Thanks again.


Mal

[drpetemurray]

Well I have not had the R75/6 very long and most of that time I have been away from home.


There was too much end float, so I thought she would be good following adjustment.

Any ideas????

I know some of you enjoy seeing any custom tools. So here is my tool for adjusting end float on rocker arms.
2L2A9355.jpg

Check the rocker box for being square and the proper distance apart. I think the measurement should be between 200 to 201mm.
do verify the suggested spec,

[malmac]

Pete

I will certainly check that measurement on both sides.

Right side seems good, the left therefore should be different. mmmm

Thank You.


Mal

[drpetemurray]

Pete

I will certainly check that measurement on both sides.

Right side seems good, the left therefore should be different. mmmm

Thank You.


Mal

Mal:

Correction to spec. For the Rocker Blocks that measure 22 mm wide for the /5 the ID measurement you want is 71 mm between blocks.
The 200-201 mm is for clutch cable adjustment. Sorry the last post was prior to am coffee.

[malmac]

Hi Pete

I will measure the set up and confirm that the measurements you suggest make sense.
Will report back when I have had a look - maybe today I will have an opportunity.

Enjoy that coffee.


Mal

[malmac]

well I measured up the distances between the blocks.
My blocks are 25mm not 22 mm

Left cylinder
top - 67.92
bottom 67.87

right cylinder
top 68.2
bottom 68.35

Given that it is the left cylinder that seems to "TIC", and it has less variation than the right, maybe that is not the cause.

Back to the drawing board.


Mal