[urq] k-jet rebuild

[Patrick Carlier]

Thought I'de share this with the list .
It is quite possible to open up the k-jet fuel distrubutor .
Clean it and put it back together again . Did it two days ago .

Mine was stuck .
When I re installed the fuel system , by habit I pushed the metering plate .
Expecting the typical bounce back .
Nothing happend , it was stuck as if it was fused .
Further ivestigation showed the metering plate was ok , but
the fuel distributor the plunjer would'nt move .

So I cleaned up the workbench ( took half a day :)) , put some paper towel 
on it .
And carefully took it apart . First took off the two screws on top .
Then put it upside down in a vice and gently removed all the bottom screws .
Carfully , there are springs inside .
Then wiggled of the bottom side .

Took out the rvs membrane , carefull very suscpetible to damage , and then 
plunjer with its housing .
Removed everey non metal part from the plunjer assembly and soaked it in 
WD40
overnight . It was still stuck , so I applied a little force to push it out 
.
No hammering , but a c-clamp kinda thing , with wooden blocks protecting the 
metal .
Cleaned it in degreaser and that did the trick . It's moving again .

At first I put it back together again with nothing more then a gentle 
cleaning .
But then it leaked fuel between the two halfs .
So I had to take it apart again , and applied a very light coat of liquid 
sealant .
to both halves . Aplied with a small nylon brush .
The stuff I used was red , so it was very visible .
Be carefull not to apply te coating to the tiny little holes and passages .
And the coating has to be be fuel resistant ofcourse  .

After that , the K-jet was tight as a drum and fully functional !
A new metering head is listed 2300? ( 3,500USD ) in etka .
Well worth the effort of trying to revive it , isn't it .

One cant't help but to admire the craftmanship it took to build the  k-jet .
It's obsolete now , but in carburettor day's it was quite an invention .
And as a metal worker , I'm sure I could'nt accomplish that kind of 
precision .
Fi , between the moving plunjer and its housing , there isn't a single seal 
; o-ring , pistoi ring , whatever .
Still , it has 4 bar of fuel on it , and it doesn't leak a drop .

Anyone wants to see pictures of the internals , drop me a mail and I'l send 
them .


Pat
1981 WR engine running !!