Rocker alignment with valve stem

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Mofosheee

Mofosheee

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Hello Access gurus

While assembling my 850 Commando cyl head I noticed that one ex valve rocker valve adjustment screw is not contacting the center of the valve stem (unlike the others)
Is it an acceptable practice to move a rocker into alignment with the insertion of additional thrust washers? Please advise.
And thank you again!




Thank you
Rocker alignment with valve stem
 
There is a thing everyone knows , of its fore & aft ' alignment ' , where it swipes even across the center .

Technically - it goes about the same measurement each side . Starts one - across - & back . For Minimal total offset .
IF it were all to one side , the rocker thrust gives the guides a hard time .

Thus , yours should all be about the same . Even if it is laterally . Gross Offset would put sideload on the valve stem , with premature wear .

Rocker alignment with valve stem


Rocker alignment with valve stem


Second aint norton , but spacers & shims are a ' hot set-up ' , eliminateing the thwackery washers thwack , if theyve worn a ledge on the arm .
Used to be common to grind solid spacers to ' true ' ( To Suit ) Thickness . Those Shims would act as a thrust washer - so no harm there .
Rocker alignment with valve stem

Eres the orrible cheap'n nasty Thackery Washers . Cor , no wonder they went bankrupt .
 
Ignore all the numbers . Princple of neutral stem loading . Less valve rock . etc . Likely a more appropriate illustration available . but you cant have everything .

Rocker alignment with valve stem
Rocker alignment with valve stem


The RELEVANCE is , altered deck hights , skimming , & pushrod length , alter the Neutral Point of the valve actuator /
tappet adjuster tip . There used to be captive ball end adjusters , And allen key screws / adjusters .

these below are Ball end - for something else . Less Friction / drag .

Rocker alignment with valve stem
 
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My RH10 has one valve off like yours. Others are fine. Must have been a monday morning casting.

Jim Comstock did the valve job and suggested using mushroom head adjusters which I did. Also shimmed out the arms and tossed the Thackerys.
 
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Mofosheee said:
Is it an acceptable practice to move a rocker into alignment with the insertion of additional thrust washers?
Click to expand...

Yes, you can replace the Thackeray/spring washer if necessary (or all Thackerays) with suitable width inner spacer and outer shim 'as required'.

alternate rocker thrust washer

Does anyone know if there are spacers available to replace the thrust/thackery washers for the rockers, thanks
www.accessnorton.com www.accessnorton.com

Rocker alignment with valve stem
 
L.A.B. said:
Yes, you can replace the Thackeray/spring washer if necessary (or all Thackerays) with suitable width inner spacer and outer shim 'as required'.

alternate rocker thrust washer

Does anyone know if there are spacers available to replace the thrust/thackery washers for the rockers, thanks
www.accessnorton.com www.accessnorton.com

Rocker alignment with valve stem
Click to expand...
I wish I had known this when I built my motor
I did away with the Thackeray washer's and shimmed the rocker arms to the centre of the valves !
Oh well
 
Seems like there is some contradictory information floating around on this topic.
On the one hand I hear that offset rockers are good because this leads to valve rotation. And on the other hand, it is bad is bad because it produces undesirable loads on the guides and valve stems. Plus it makes a mess of the end of the valve stem.
1. Does anybody have any solid information that offset rockers actually leads to valve rotation in a Commando?
2. Is valve rotation really a good thing?
3. And if the answer to 1. or 2. is no, then why bother with offset rockers??
 
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End result...............bronze spacers replaced the Thackeray's and mushroomed adjusters installed.
FWIW, for me it made sense to me to line things up.
 

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I used spacers from RGM lining the rocker central on the valve head. No issues noted at 10k. Usually like to use valve stem caps as they are easier and cheaper to replace than valves but this adds other issues that need to be dealt with so did not do it with
current bike.
 
Matt Spencer said:
Ignore all the numbers . Princple of neutral stem loading . Less valve rock . etc . Likely a more appropriate illustration available . but you cant have everything .

View attachment 93465View attachment 93466

The RELEVANCE is , altered deck hights , skimming , & pushrod length , alter the Neutral Point of the valve actuator /
tappet adjuster tip . There used to be captive ball end adjusters , And allen key screws / adjusters .

these below are Ball end - for something else . Less Friction / drag .

View attachment 93467
Click to expand...
Would like to know where I could get another set of ball end adjusters ...haven't seen them for years
 

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-standard esoteric reply here
Although offset rockers tend to rotate valves, the normal winding and unwinding of the spring coil causes rotation unless the spring is tighter than necessary for the RPM. Should never be an issue in this engine. Shimming rockers to the center of the valve is universally applied to engines, the only reason they have springs on the shafts is to save the production time of shimming each one. Valve lash caps add durability at high RPM also, but in a near-stock engine built with modern, high-quality valves I won't spend the extra effort to use them. I used to build my street engines to race spec (with regards to material and build, not performance) but I gave that up after decades of experience proved there was no return but for my peace of mind. Eventually that balanced with my peace of wallet and labor time.
 
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