Rocker Arm Repair

[lyletrudell]

I did a valve job on my Honda yesterday.
The valve stems were worn from the rockers rubbing on them for 70K miles. So I also reground the valve stem ends back to square.
If the valves were worn then so are the rocker arms.
Yep, they had a groove/indent from rubbing against the top of the valve stem. It was about .003-.004" deep.
This would make the valves rock and wear out the valve guides quicker.
The large end of the rocker arm that rubs against the cam looked good.
I didn't want to sand or stone them, it would not be square and the radius would be messed up, causing faster wear.
So being a machinist I have to do things the right way.
First I checked the radius on the optical comparator.
Dressed the radius on a grinding wheel for the surface grinder.
Made a simple jig to hold the rocker arm.
Then ground off about .004".
Buffed for final finish.
Perfect radius, parallel to camshaft and smooth finish is restored!
Good for another 70K!
See photos section for before and after.
Lyle

[lyletrudell]

Bill, brought up a very good point about grinding off too much material and not having enough travel on the cam eccentric shafts.
Something to watch for when working with any motorcycle type valve design!
I ground the valve seats a little deeper when I did a valve job, so that might make up the difference.
Also, I only ground the rocker arms until the spot cleaned up were the valves were already running, so if they were in ajustment before they should be fine now. I probably removed .001"-.002 material.
But, when I re-assemble I will check tolerances and post what I find.
Lyle

--- In
anzhonda600owners@yahoogroups.com
, "lyletrudell" wrote:
> I did a valve job on my Honda yesterday.
> The valve stems were worn from the rockers rubbing on them for 70K miles. So I also reground the valve stem ends back to square.
> If the valves were worn then so are the rocker arms.
> Yep, they had a groove/indent from rubbing against the top of the valve stem. It was about .003-.004" deep.
> This would make the valves rock and wear out the valve guides quicker.
> The large end of the rocker arm that rubs against the cam looked good.
> I didn't want to sand or stone them, it would not be square and the radius would be messed up, causing faster wear.
> So being a machinist I have to do things the right way.
> First I checked the radius on the optical comparator.
> Dressed the radius on a grinding wheel for the surface grinder.
> Made a simple jig to hold the rocker arm.
> Then ground off about .004".
> Buffed for final finish.
> Perfect radius, parallel to camshaft and smooth finish is restored!
> Good for another 70K!
> See photos section for before and after.
> Lyle