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JP2M hi or low compression?


fittie

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5 minutes ago, Capella247 said:

On the odd occasion when I've been on a river I ve dialled the valves out on my JP.  But then thought better of it because when dialling out there is a lot of soot and smoke. Once all the way out they don't leak, but when out Ive also noticed sparks from the drilled hole in the valves?  Is that normal or a sign that something is up that needs sorting? Cheers Tom 

They only work fully in or fully out. Yours are leaking on low compression 

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13 hours ago, RLWP said:

They only work fully in or fully out. Yours are leaking on low compression 

Thanks.  When fully out there is the odd whisp of smoke and the spark or two from the drilled hole.  But lots more when actually dialling out, is there anything I can do to seal up? Thought maybe greasing.  Reading other threads theres mention that they soot up after a while. 

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They do soot up

 

This is the double sided valve:

 

valves-2.JPG

 

which seals into the seat in the head:

 

valves-1.JPG

 

and into the back of the Low chamber:

 

valves-4.JPG

 

valves-3.JPG

 

To make them seal properly, you have to take the valve apart, clean up the seats and ideally lap the valves in

 

I'd leave them in high

 

Richard

 

MORE: looking through out JP manual, it shows a JK head with a blank instead of the c/o valves ^_^

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16 minutes ago, RLWP said:

They do soot up

 

This is the double sided valve:

 

valves-2.JPG

 

which seals into the seat in the head:

 

valves-1.JPG

 

and into the back of the Low chamber:

 

valves-4.JPG

 

valves-3.JPG

 

To make them seal properly, you have to take the valve apart, clean up the seats and ideally lap the valves in

 

I'd leave them in high

 

Richard

 

MORE: looking through out JP manual, it shows a JK head with a blank instead of the c/o valves ^_^

Thanks for the advice and sharing the pictures Richard,   It’s really helpful to see how they work.  Tom

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24 minutes ago, RLWP said:

They do soot up

 

This is the double sided valve:

 

valves-2.JPG

 

which seals into the seat in the head:

 

valves-1.JPG

 

and into the back of the Low chamber:

 

valves-4.JPG

 

valves-3.JPG

 

To make them seal properly, you have to take the valve apart, clean up the seats and ideally lap the valves in

 

I'd leave them in high

 

Richard

 

MORE: looking through out JP manual, it shows a JK head with a blank instead of the c/o valves ^_^

Lapping them in is easier said that done, keeping the assembly parallel whilst lapping is near impossible. I leave mine well alone, only operating them once in a while for that mad professor experience and to oil them during servicing. 

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11 minutes ago, Capella247 said:

I had to google lap / lapping.   Thankfully safe search was on 

Same process as sealing the valves in the cylinder head, but unlike those, the changeover valve has no guide to support the valve whilst carrying out the operation. 

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34 minutes ago, BWM said:

Lapping them in is easier said that done, keeping the assembly parallel whilst lapping is near impossible. I leave mine well alone, only operating them once in a while for that mad professor experience and to oil them during servicing. 

Smoke, explosions, flying soot - it's fun operating those valves

  • Haha 1
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