Valve guide clearance R12?
Posted: Mon Aug 17, 2020 2:31 pm
The cylinders of my R12 had the holes for the valve stems worn so one of our specialists put in brass inserts. After the first couple of minutes riding the cylinders got hot (200+ Celcius), an exhaust valve got stuck and the valve guide had a press fit which was a bit too loose so it had moved.
The specialist redid it and I checked the clearance between the valve stem and valve guide to make sure it was OK. It was 0.07mm (diameter) so that looked good to me.
Apparently that wasn't enough because within 2km after assembly again the exhaust valve got stuck.
Does any of the veterans have a recommended clearance for these old sidevalves? I think I'll go for more than 0.07mm but what is reasonable before it gets too much?
Thanks for any advice,
Peter
The specialist redid it and I checked the clearance between the valve stem and valve guide to make sure it was OK. It was 0.07mm (diameter) so that looked good to me.
Apparently that wasn't enough because within 2km after assembly again the exhaust valve got stuck.
Does any of the veterans have a recommended clearance for these old sidevalves? I think I'll go for more than 0.07mm but what is reasonable before it gets too much?
Thanks for any advice,
Peter