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KWR
KWR
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71 Thunderbolt Oil pressure and idle speed
#825625 10/04/20 8:38 pm
Joined: Mar 2020
Posts: 46
Likes: 1
R
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Finally took my 71 Thunderbolt on it's first ride. My question is about the oil pressure. when it was cold idle was 40 psi and revved up close to 60. I am using 20/50 HD oil. After riding it to get it warmed up the pressure is 20 at idle and 40 revved up. Do you think this is ok? Also what is a good idle speed? I can not find ant spec for the oil pressure or idle in my service manual.

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Re: 71 Thunderbolt Oil pressure and idle speed
RUSS TILLEY #825627 10/04/20 8:53 pm
Joined: Mar 2006
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Likes: 11
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Oil pressure sounds good. Cold pressure is pretty meaningless, it's the hot numbers that count and those sound fine. Rough rule of thumb is 10 psi per 1000 rpm. Set the idle at around 1000-1100 rpm. Pretty easy with one carb. That's a nice looking bike. 70 and up bikes have some nice engine updates like a better oil pump.


1978 Bonneville T140E
1974 Trident
1970 BSA Thunderbolt
1971 Norton Commando
1972 Norton Commando
1973 Norton Commando
1974 Norton Commando
2018 Kawasaki Z900RS


Everything will be alright in the end. If its not alright, its not the end.
Re: 71 Thunderbolt Oil pressure and idle speed
RUSS TILLEY #825638 10/04/20 10:34 pm
Joined: Oct 2007
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oil pressure sounds fine, a good idol speed would be around 1000-1200 rpm give or take


"There's the way it ought to be and there's the way it is" (Sgt Barnes)
Re: 71 Thunderbolt Oil pressure and idle speed
RUSS TILLEY #825642 10/04/20 11:37 pm
Joined: Mar 2020
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Thanks for the information. It has been a journey to rebuild this bike and I have received a lot of good info from this forum.


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