Mushroom tappet

Egholt · Mar 5, 2015

Where to buy mushrom tappets in europe ?

Michael

L.A.B. · Mar 5, 2015

http://www.rgmnorton.co.uk/buy/mushroom ... %5D_80.htm

pete.v · Mar 5, 2015

Egholt said:
Where to buy mushrom tappets in europe ?

Michael

Get fresh adjuster nuts also. Threads deform over time. And oil them up. Don't over tighten, these hard threads can chip and spread damage.
http://www.rgmnorton.co.uk/buy/std-rock ... nut_82.htm

Hobot · Mar 5, 2015

I was told here its ok to grind 'shoorm heads down to thread in w/o pulling rocker spindle. it that really so and does it nullfiy the 'shroom advantage?

Onder · Mar 5, 2015

Some heads arent manufactured correctly and the head of the tappet pin (adjuster) isnt fully on the head of
the valve. Using the mushroom adjuster helps to some extent so Id no be grinding any off in that case.
By head had only one valve with this problem but one is too many. Jim Comstock told me it isnt unusual and
if I had half of the face of the adjuster on the head Id be ok.
There is much to be said for valve caps. They widen the head a little bit but more importantly if they wear
you just toss and replace.

Hobot · Mar 5, 2015

Re: Mushrom tappet

OH Yeah valve caps, Peel had caps + mushrooms but don't know about Trixie Combat yet to fit new 'shrooms on hand or not.

pete.v · Mar 5, 2015

hobot said:
OH Yeah valve caps, Peel had caps + mushrooms but don't know about Trixie Combat yet to fit new 'shrooms on hand or not.

Lash cap are a viable solution. Although they do not correct for poor geometry, they can prolong the tip of the valves and be a rejuvenator.

My Combat head suffered from what appeared to be a jig full of shavings type of mal-manufacturing. The entire head was sort of tired and Jim thought it not to be a good candidate for re-machining the guide hole to correct the geometry. I sold it as a functional head, which it was, and modded up a RH1 to a respectable performance head.

Brooking 850 · Mar 5, 2015

+ 1 with Onder
I run lash caps on the exhaust valves of my RH10 head, with mushroom tappets, as if not, the standard tappet tends to erode the edge of the valve tip.
It also seems there could be an inherent fault in some heads with the RHS exhaust valve being the worst with misalignment to the rocker arm tip and tappet.
Regards Mike

Frankie17 · Mar 6, 2015

If you are looking at buying mushroom tappets look for the correctly manufactured ones with copper plated threads

the threads are copper plated prior to heat treatment / hardening of the tip this stops the threads becoming hard and avoids the chip issue
the quality Uk made triumph tappets are also made this way

Danno · Mar 6, 2015

On the misalignment issue, has anyone else removed the silencer springs from the rocker shafts and side=shimmed the rockers to center them over the valve heads? I did this years ago to no ill effect except increased tappet noise.

john robert bould · Mar 6, 2015

Mushroom tappets ,will still contact the valve in the same plain ,the extra metal in the bigger head will do nothing,its about the sweeping arc and tappet rad , lash caps will prevent the tappet from deforming the valve stem edge in badly "off set" situations ..so basically the extra mushroom idea doe's not work ,as said it's just more metal around the contact area ,doing nothing.
I have used floating ball type, as a flat sits on the valve wear is very low,as long as you dont go mad with rev's they are OK, over rev to valve float and the ball can spin in the cup and hold the valve off its seat. other than that they are good. I think Ducati had them :?:

Onder · Mar 6, 2015

Balls ends were on later Tridents. The cup that holds the ball could break up. I never had that
happen on my street bike but apparently it does happen.
MB-Porsche type is supposed to offer the same idea with less chance of failure.
I went to small head allen adjusters with valve caps.

johnm · Mar 6, 2015

john robert bould said:
I have used floating ball type, as a flat sits on the valve wear is very low,as long as you dont go mad with rev's they are OK, over rev to valve float and the ball can spin in the cup and hold the valve off its seat. other than that they are good. I think Ducati had them :?:

And the NSU Sport Max

http://www.telegraph.co.uk/motoring/mot ... 69000.html

http://www.audi.com/corporate/en/compan ... -1955.html

which did rev a bit - all the way to the 250 GP world title.

A friend has a genuine Sportmax engine. Each complete bike was sold with a spare engine and he has owns the spare engine for Rod Coleman' Sportmax.

(Plus about 50 standard Max and Supermax engines and bikes !!!)

Hobot · Mar 6, 2015

On the misalignment issue, has anyone else removed the silencer springs from the rocker shafts and side=shimmed the rockers to center them over the valve heads? I did this years ago to no ill effect except increased tappet noise.

Shims instead of spacer springs is common among straw grasping racers and bored mechanics but niether locating method has any affect on the head innate ringing like a bell. Peel's hogged out Combat head was-is shimmed and ring dinged like they all do but was un=harmed after peg bouncing tach needle over rev. You do have to pay special attention to keep shim's ID on order and placement when taking apart. Seems like I remember Peel's mushrooms got flat spots afterwards and don't know if Canaga replaced them or not. Micheal Starkey of British Toys in North Carolina did main over haul of Peel's head with shimmed rockers. I think he may be dead or stroked out as no response to emial for a few years.

Danno · Mar 6, 2015

john robert bould said:
Mushroom tappets ,will still contact the valve in the same plain ,the extra metal in the bigger head will do nothing,its about the sweeping arc and tappet rad , lash caps will prevent the tappet from deforming the valve stem edge in badly "off set" situations ..so basically the extra mushroom idea doe's not work ,as said it's just more metal around the contact area ,doing nothing.
I have used floating ball type, as a flat sits on the valve wear is very low,as long as you dont go mad with rev's they are OK, over rev to valve float and the ball can spin in the cup and hold the valve off its seat. other than that they are good. I think Ducati had them :?:

I am the sort that likes to continually mess with things, but shimming the rockers and removing the springs has some small friction reduction effect plus it positively locates the tapper in the center of the valve stem tip, which reduces scrubbing and keeps the cam lifting the valve instead of pushing the rocker from one side to the other, wasting kinetic energy and vibrating the pushrods. It's definitely noisier, though.

Nater_Potater · Mar 6, 2015

Onder said:
Balls ends were on later Tridents. The cup that holds the ball could break up. I never had that
happen on my street bike but apparently it does happen.

Happened twice on my '72 Triple, and not from over-revving. It didn't show up in normal operation. Only during a valve adjusting routine was it noticed when the feeler gauge acted like it was catching something while inserting. I wonder what would have happened had I unleashed her on a spirited romp...

Nathan

Snotzo · Mar 6, 2015

The Porsche 911 uses what are commonly called 'elephant feet' ball in cup ends on the tappet adjusters. The cup edges are swaged around the ball so cannot come off. Something similar are the cups used in GM speedway engines, but these are loose cups, and can easily become displaced.

Tappet adjusters incorporated in the ends of rocker arms were always a cheap and convenient means of adjustment.

Nater_Potater · Mar 9, 2015

Snotzo said:
The Porsche 911 uses what are commonly called 'elephant feet' ball in cup ends on the tappet adjusters. The cup edges are swaged around the ball so cannot come off. Something similar are the cups used in GM speedway engines, but these are loose cups, and can easily become displaced.

Tappet adjusters incorporated in the ends of rocker arms were always a cheap and convenient means of adjustment.

I like the looks of those. L.A.B., Comnoz; any input as to whehter or not there's enough room to install something like these?

Nathan

comnoz · Mar 9, 2015

Nater_Potater said:
Snotzo said:

The Porsche 911 uses what are commonly called 'elephant feet' ball in cup ends on the tappet adjusters. The cup edges are swaged around the ball so cannot come off. Something similar are the cups used in GM speedway engines, but these are loose cups, and can easily become displaced.

Tappet adjusters incorporated in the ends of rocker arms were always a cheap and convenient means of adjustment.

Click to expand...

I like the looks of those. L.A.B., Comnoz; any input as to whehter or not there's enough room to install something like these?

Nathan

You can if you retap the rocker arm and use shorter pushrods.

But- they add weight and are not really needed if you use Kibblewhite valves with the stellite pad. Jim

john robert bould · Mar 13, 2015

Problem with rockers and tappets ,the tappet and valve tip becomes "bedded" into each other, the radius on the adjuster forms a corresponding grove in the valve stem, then "we" turn this bedding into a new position .if the ball end of the adjuster as not worn then a new "bedding" re-starts . With rapid wear. It's a constant process , bed-adjust-re-bed,adjust.......... tipped valves and super hard adjusters help. So dont skimp on cost!!!

Mushroom tappet

Egholt

L.A.B.

Moderator

pete.v

Hobot

Onder

Hobot

pete.v

Brooking 850

Frankie17

Danno

john robert bould

Onder

johnm

Hobot

Danno

Nater_Potater

Snotzo

Nater_Potater

comnoz

john robert bould

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