As above guys.
My loverly 'new' 160 had started to feel a little underwhelmed over the last few gallons so
I did the obvious took the rocker cover off to adjust the tappets and found the inlet valve
spring broken. I ordered a new one from Probuild fitted it, adjusted the tappets and took
her flying again. She still feels a little lack lustre any ideas where to look next Gents?

What caused the spring to fail? Maybe too hot? Could the engine be running too lean?

A new 1.60? How many flights has it seen? If there are a fair amount of flights it may be ring and bearing time. Barring that two things come to mind:
Valve is bent.
Valve seat not sealing.

Cheers for replys Gentlemen.
Engine is previously owned so as for how lean, how many etc I couldn't say for certain.
Other than it appeared very clean and in a little used airframe.
Since I've had it it has been sympathetically run on the rich side, indeed the HSN was 1.5
turns out when I got it,I added a further 3 clicks which has a beautiful smoke trail.
The broken spring wasn't immediately apparent. The inlet seemed a little softer than exhaust
which is why I replaced it and the break became obvious only when the collets and retainer
came off.
Petec should I assume the ring and bearing are service parts on these and would this be where
you would start?
I will get a new valve as well but how or do you have to lap them in?
Atvb
John

Yes the ring and bearings are a standard service part on these engines. I know guys who replace them every year, amount of flying, lubricant and just environmental conditions play a big part in that service interval.

Aa for the valve, some guys lap them using toothpaste, other guys like me just drop the new ones in and go fly. Just be certain the valve seat does not have any carbon or any other type of build up on it.

You're a Star as always P.
I''ve ordered the bits from Probuild already and will report back
as and when I get them fitted.
All the very best
John

Have a pint of your favorite Wychwood Ale for me.

Pete

John,

On the valve, turn the engine by hand and closely listen for compression leak at the cargo and the exhaust, most probably the valve turned from it's sitting position and it is leaking, as Petec said, tooth paste(with baking soda), or I use Mothers Wax for aluminum, I turn it as slow as I can with a dremel, I had to do this repair on a friends 160 due to the same issues as your lack of power.

Good luck

Alejandro P.

ERR

Not quite sure about this but apparently confession is good for the soul........

I thought about the main problem I'd had with my 63's and 110's which
was usually traced to the 'plumbing' and various leaks along the tubes...
So I replaced all the tubing, gave it a good wipe down and look before
the final BIG STRIP...I then noticed that the needle valve appeared to
be rubbery (no not lovely in Japanese but flexible)....
Long story short valve assembly had unscrewed itself from the carb
and guess what? It didn't want to develop much power.
The good news is Sunday was perfect weather here and My epic 160
is back to it's old self.

[sm=spinnyeyes.gif]

No worries....everyone has an off day. Now you have the parts to rebuild when the ring and bearings need replaced.

It's all good Petec.
You'll be happy to learn I had a pint (OK several pints) of Hobgoblins finest and toasted your good self.
Best
John

Hobgoblin is my FAVORITE ale. Just too hard to find it where I live. Thanks for having a few for me.