1 [solved]Valve clearances Sun Jan 27, 2019 9:29 am
tinyspuds
Life time member
Morning all,
Bike 1985 K100RT 57k miles
Last week the engine shut down at 60 mph with no prior warning. I was able to re-start after a few minutes but the temp gauge rose to 3/4 and the fan cut in. It has re-started several times since and run stationary at tickover until properly warmed up without issue.
I have plenty of oil - oil and filter changed 800 miles ago. Coolant is circulating, thermostat is operating, fan cuts in where it should.
Compression test with WOT showed around 100 psi on all 4.
I've taken the valve cover off and there is no obvious physical damage. I've measured valve clearances and found:
All exhaust are .25 - .30 tick v.g.
Inlets:
.15 .10+ .10+ .10+
(my gauges only have .05 increment so 2 thru 4 are an easy .10 but won't take .15).
To narrow it down the 3 suspect inlets are a nice sliding fit for .005 in.
Three questions:
Do these clearances make any sense at all? What I've read says tightening exhaust pretty common, inlet: pretty rare.
If they do make sense, as opposed to me just not knowing what I'm doing, is this likely to have caused the stop and overheat (even though it re-started fine after just a few moments)?
If I have measured correctly, is this a don't ride it til fixed scenario?
I have already had a lot of much needed support on this under a different thread for which I am grateful. However, the bike I normally work on is a 1954 Enfield Bullet, so absolutely not too proud to receive more input.
Thanks, Stu.
Bike 1985 K100RT 57k miles
Last week the engine shut down at 60 mph with no prior warning. I was able to re-start after a few minutes but the temp gauge rose to 3/4 and the fan cut in. It has re-started several times since and run stationary at tickover until properly warmed up without issue.
I have plenty of oil - oil and filter changed 800 miles ago. Coolant is circulating, thermostat is operating, fan cuts in where it should.
Compression test with WOT showed around 100 psi on all 4.
I've taken the valve cover off and there is no obvious physical damage. I've measured valve clearances and found:
All exhaust are .25 - .30 tick v.g.
Inlets:
.15 .10+ .10+ .10+
(my gauges only have .05 increment so 2 thru 4 are an easy .10 but won't take .15).
To narrow it down the 3 suspect inlets are a nice sliding fit for .005 in.
Three questions:
Do these clearances make any sense at all? What I've read says tightening exhaust pretty common, inlet: pretty rare.
If they do make sense, as opposed to me just not knowing what I'm doing, is this likely to have caused the stop and overheat (even though it re-started fine after just a few moments)?
If I have measured correctly, is this a don't ride it til fixed scenario?
I have already had a lot of much needed support on this under a different thread for which I am grateful. However, the bike I normally work on is a 1954 Enfield Bullet, so absolutely not too proud to receive more input.
Thanks, Stu.
Last edited by tinyspuds on Sun Jan 27, 2019 3:34 pm; edited 1 time in total (Reason for editing : Imperial gap added)