R25 Idles Ok coughs at higher revs

[Ligarosa]

@Eppo I checked the inlet/outlet ports and they where dry, also sprayed brake fluid to test valve sealing is ok.

While engine operates there is alot of oil dropping from rocker arms (due to axial loosenes probably). Also the engine does not seem to burn oil so there is no path to ignition chamber.

Maybe I could use a bench vise to press the rocker arms to fix the looseness? If so does anyone know the tollerance of the fitting?

[Ligarosa]

[Ligarosa]

@Eppo I checked the inlet/outlet ports and they where dry, also sprayed brake fluid to test valve sealing is ok.

While engine operates there is alot of oil dropping from rocker arms mainly for inlet (due to axial loosenes probably). Also the engine does not seem to burn oil so there is no path to ignition chamber.

Maybe I could use a bench vise to press the rocker arms to fix the looseness? If so does anyone know the tollerance of the fitting?

[4Taktix]

Good Morning Ligarosa,
there is no explicit value given, the manual just says (in german):
"Spielfrei, aber leicht drehbar"
-> without any clearance/play, but easily moveable.
I'd say this is about 0,05mm.
This is valid for the narrowest spot, in most cases in the upper half of the front face at the thrust end.
( opposite of the valve rods )
You can probably notice an area there, looking polished and shiny. This is where the rocker had contact and the
narrowest spot.
The Blocks were just pressed onto the axles, in many cases you can use a clamp to tighten the clearance.
I'd put a feeler gauge 0,05mm between rocker and blocks on top half, then clamp it to tighten.
Then remove the gauge and check if the rocker moves easily whithout any resistance.
It's a bit fiddling around, try and error.
Problem is the press fit - blocks on axle. If it is too loose, the clearance that you set before, will likely
change again by tightening the head bolts. Just try, mount the head and finally check rocker clearance again.

[rolf]

´so eng wie möglich aber absolut freigängig