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Tappet adjusters length

Trinorvin

Forum Website User
VOC Member
Hello everybody,
after almost one leisure year spent tooverhauled Girdraulic forks, twisted rear frame upright with a homemade gig, timingchest spindles, gears, camshaft etc, I discover that there are two differentrocker tappet adjusters length and the longer tappet adjuster fouls the bottomof the cap (on each reversed side). Before having dismantled thebike, the engine was running well and I think that wear compensate the too longtappet adjuster. The push-rods are around 6” length and the tappet adjustersare:

shorter; 20,97mm – 4,98mm(recess)= 15,99mm. Longer; 21,89mm –2,47mm(recess)= 19,42mm.
I have seen in the spares list the existence of a Clutchadjuster ET27/1AS longer than the tappet adjuster ET27 and I guess that theprevious owner found whatever on the bench…
Is somebody having a tappet adjuster out the engine as sparecould measure the length and recess depth?
Another worrying thing is the lostcompression after onestaying year even when the tappet adjuster are removed (of course spark plugfitted)?
Thanks for your help.
Trinorvin
 

vibrac

Well Known and Active Forum Website User
VOC Member
Not 'around 6" ' in length there are 3 pushrod lengths ET43 ET43/1 ET43/2 differing by a 1/16 of an inch obviously 1/8 difference is a lot to consider. its not all tappets (as the noisy vincent owner is often told :))
 

clevtrev

Well Known and Active Forum Website User
VOC Member
Pushrod length requirement can vary a lot, due to :- muff height, valve seat height, and a million variations in the head.
If you have had new seats installed, you may want a loong rod, cavitated seats mean you would want a short rod.
 

vibrac

Well Known and Active Forum Website User
VOC Member
Ihave measured the push-rods; one is 152,12mm of length, the other one 152,40mm
thats a spot on 6" ET43 and a slightly worn 6"
obviously you will shell out £15 or so for a couple of new adjusters but
are you certain that both valve stem collars are pushed down hard on the shoulder of the valve?
 

Big Sid

Guest
Coventry Spares stocks a range of pushrod lengths that can result in a workable situation where the adjuster is positioned
At a desirable height , and also offers shorter adjusters too . Pushrod bottom ball ends wear away generally as a result of a poorly machined follower socket , often too small and somewhat rough so wearing away the ball end in operation . This was not uncommon in NOS followers thus affected some Vincents from new . Sid .


Sent from my iPad using Tapatalk
 

Trinorvin

Forum Website User
VOC Member
Whaow, I’m the happiest man, the Comet has fired today and ridetested on 15 kilometres! The engine hasrecovered compression after blowing air and WD40 in the cylinder through thespark plug hole and waiting 3 days (good advice from David, thanks). Ishortened off the longer tappet adjuster for one millimetre and now it does notfoul the cap. The push rods seem good, only one is 0,3 millimetre shorter, theball ends are nice.
Making up inventory; in the future I will replace push rodsand both tappet adjusters when I will check timing chest after few kilometres(the shorter adjuster has crumpled thread as described in KTB); the Girdraulic spindles needto be loosen as the forks are tight; RFM seems ok..
Thanks all for your help
Trinorvin
 
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