Lowest safe idle.
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From: Nunya.
Lowest safe idle.
What speed do you all guys idle at? The M8 came out at 850 but now it's 950. Shovel heads and Evo's we idled them ridiculously low and they sounded great. Steve, Scott or mogollon or another builder what lowest idle speed do you believe is safe for an M8. I've idled mine back to 900 but want to go lower.I know a cam can dictate idle but just in general and yea I'm going to an RS468 at some time too.
Peace.
Peace.
Last edited by Agoober; Nov 19, 2019 at 08:20 PM.
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What speed do you all guys idle at? The M8 came out at 850 but now it's 950. Shovel heads and Evo's we idled them ridiculously low and they sounded great. Steve, Chris or mogollon or another builder what lowest idle speed is safe for an M8. I've idled mine back to 900 but want to go lower.I know a cam can dictate idle but just in general.
Peace.
Peace.
Last edited by Steve Cole; Nov 19, 2019 at 08:33 PM.
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From: Nunya.
To me it depends on the build. Go out and get yourself a good Oil Pressure gauge and get it installed. Run the bike around until at full operating temperature and see where the pressure is at after its sitting and idling for several minutes on a Hot day, say 80 Deg F and above. You should then have the oil temperature up into the 250 - 280 F range. If you have a fan on the oil cooler if your bike is equipped with one, you may need to un-power it during the testing. This will show you what HD says is good, the TwinCams typically would drop to about 3 - 5 psi which I did not much care for. The M8's are better but with all the oil pump changes they have moved around. You can drop the idle speed to whatever oil pressure you feel is safe at and idle. Since these are roller bearing engines they do not take much but the cam and lifters are where my concerns are from as there is no roller bearing in the cam plate and the lifters need pressure to stay pumped up as well.
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At idle I would live with it as low as 8 - 10 psi but no lower. Remember the load does not change on the camshaft but the higher the engine RPM the more times it see's the load in a minute of time operation.
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If and when you check your oil pressure at idle and adjust your idle would you mind sharing your findings on this thread. My M8 107 after the S&S 475 cam install has a Idle of 850ish when warmed up and I've been wondering if I should have that bumped a bit. Thanks
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Last edited by hellonewman; Nov 21, 2019 at 10:47 AM.
