I am planning to convert to Allen socket valve adjusters (on a Mk3), and am wondering whether the mushroom versions are worth considering? The larger contact area should prevent dishing of the valve tip after prolonged use, but has anyone found any drawbacks?
Andy
Andy, The best fix is to…
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Mushroom valve adjusters
I have fitted these to two of my bikes, and they do make the engine sound quieter. A friend remarked on this after we had reset the tappets on my P11A Ranger 750.You can only fit them with the cylinder head off, as there is no clearance while the head is still in place. The only draw back would be that i can see, is the adjustment, can be a tad tricky, using an Allen key to adjust the valve settings.
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Mushrooms & Lash caps
You should be able to fit these items with the head still in place, although it is much easier with it off. First run the engine until it is hot. Fully loosen all the rocker arm adjusters. Then remove the rocker end caps and extract the spindles. Replace each spindle with a long thin screwdriver or similar rod to help keep the spindle washers from disappearing into the internals..
This will allow the rockers to be moved about to get at the valve stems and fit all the 'go better' chunks. Get the rocker bits back in their respective positions, including the pushrod ends, and then begin to spanner-up. If the rocker spindle openings feel cold / tight a few seconds with a heating device through the rocker cap hole will help here.
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Thanks all for the useful…
Thanks all for the useful comments. Now convinced that mushroom adjusters are a worthwhile upgrade. As I am currently assembling the head, it is the perfect opportunity. The only downside is the £51 price - eek! But nothing gets cheaper, so will just have to accept that.
Andy
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had one flip at high rpms,…
had one flip at high rpms, stick the valve open and then it hit the piston. just saying.....
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So, I took the plunge and…
So, I took the plunge and got mushroom adjusters from A-N. Using the standard 0,014” shims, I centralised the first rocker/adjuster on the valve tip - L/H inlet and it required 3 shims. Knowing the Thackeray washer would now be too compressed, I bought four brass spacers from RGM; these measured in a range between 0,134 - 0,140”. However, the required thickness at this first location is only 0,084”, so the spacers are way out in size, and not having machining facilities, removing potentially around 0,056” from each shim by hand could be a real pain.
Neill, you mentioned that you fitted spacers - what did you use, or did you make yours from scratch? I could I suppose get a stack of standard shims and use those, though a one-piece spacer does seem more appropriate?
Andy
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Neill, Thanks very much for…
Neill, Thanks very much for such detailed explanation about your spacers. Your installed spacers are much thicker than mine will be, but you say you shortened the rockers?
Why did you shot peen the rockers? Were you concerned about residual stress post grinding?
I see you have what looks like a neoprene (?) gasket - how has that survived?
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After shimming the rockers…
After shimming the rockers to centralise the adjusters on the valve tips in a left to right axis, I noticed that whereas the inlet adjusters contact the valve tips perfectly centrally in all axes, the exhaust adjusters contact at the inner edge of the tips - see photos (inlet photo first). Nothing that can be done about the exhaust adjuster positioning, but is that intentional/normal?
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Valve alignment
Hi Andrew,
To improve valve alignment the valves can be shortened and hardened lash caps fitted, available from RGM.
Regards, Al
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Andy,
The best fix is to fit lash caps and are most cost effective.
They're a hardened cap that fits over the top of the valve, and are easily fitted if you have the standard adjusters, because they can be screwed right out of the rocker if required.
RGM have them item 29, part No 050465