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Oil pressure at idle when hot?
#126663 10/19/07 11:48 pm
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Normal Triumph oil pressure with warm oil is between 60 & 80 psi. Anything higher at cold startup is permissible due to the inability of cold oil to flow. Anything lower than 60 at 2500 RPM usually indicates engine wear to the crank seals and/or rod big ends. Quote from RF. Is this pressure at idle or at a certain RPM?


Cliff Ginger
71 Bonneville 650RR?
73 Bonneville 750 (sold)
73 Trident
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Re: Oil pressure at idle when hot?
#126664 10/20/07 1:57 am
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Quote
Originally posted by GeeMan614:
Anything lower than 60 at 2500 RPM...
What the heck are you smoking? laughing

Is 2500 RPM not specific enough?


Don't hide 'em, Ride 'em !!

RF Whatley
Cornelia, GA
Re: Oil pressure at idle when hot?
#126665 10/20/07 3:33 am
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i dont getcha RF, doers wat i been smokin make a difrence to idle rpmes's's?


"he who laughs fast, laughs first"~Gunk
Re: Oil pressure at idle when hot?
#126666 10/20/07 1:50 pm
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OK, I misred the info. but what is normal or good pressure at idle when engine is hot?


Cliff Ginger
71 Bonneville 650RR?
73 Bonneville 750 (sold)
73 Trident
Re: Oil pressure at idle when hot?
#126667 10/21/07 12:29 am
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Born To Run
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G-Man

Have a look at this (courtesy of Dave in PA):

I'm running a 72 T120 with 20/50 synthetic motorcycle oil and I conducted a test of my oil pressure with an oil pressure guage that I attached in place of my oil pressure switch.

These are the results:

When first started:
Idle 800-900 RPM 32 psi
1000 RPM 35 psi
2000 RPM 75 psi
3000 RPM 85 psi

After about 2-3 minutes:
Idle 800-900 RPM 28 psi
1000 RPM 32 psi
2000 RPM 65 psi
3000 RPM 70 psi

After about 6- 8 minutes:
Idle 800-900 RPM 23 psi
1000 RPM 24 psi
2000 RPM 52 psi
3000 RPM 70 psi
4000 RPM 80 psi



If your numbers are anywhere close to these, ride the [email protected] out of it..... laugh

Cheers,

Steve


'77 T140J
"Vintage Bike". What's in your garage?

"The paying customer is always right."

Fitting round pegs into square holes since 1961...
Re: Oil pressure at idle when hot?
#126668 10/21/07 5:12 pm
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What is your idle pressure after a good hammering? This is when the old 7lb psi oil switch starts making the dreaded light flicker!

If I rev my engine to 10000rpm, this is how the warning light looks from space

http://farm3.static.flickr.com/2030/1674668455_9de2576679_o.jpg
Dave

Re: Oil pressure at idle when hot?
#126669 10/22/07 2:42 am
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Thank you for the replies, My pressure is about 5 lbs at idle when hot ( half hour of running). I think I need a new pump!


Cliff Ginger
71 Bonneville 650RR?
73 Bonneville 750 (sold)
73 Trident
Re: Oil pressure at idle when hot?
#126670 10/22/07 5:54 am
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not the pump thats the problem....pressure is the resistance to oil flow by bearings etc...


1970 tr6r dryframe
Re: Oil pressure at idle when hot?
#126671 10/22/07 7:53 am
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What oil are you using sport? The 'wrong' viscosity can give this symptom methinks.

Blapper redwine

Re: Oil pressure at idle when hot?
#126672 10/22/07 1:48 pm
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I read that low oil pressure at idle is probably ok (according to some factory bloke) as long as it was up at normal speeds. He also said that the oil light was a big worry to riders and that at least before 1968 oil pressure was out of mind because there was no switch fitted! I have no switch on my '67 but my big end shells are ok.

Do you have an early unit 500? The bush can wear but they generally last a long time.

Re: Oil pressure at idle when hot?
#126673 10/22/07 3:13 pm
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I have found that miles on the oil makes a difference too. Viscosity. So conventional oil like say Castrol 20/50 doesn't hold that as well as real synthetic. Unburned gas in the oil after miles also. So on a hot day say 90 degrees even fresh 20/50 will flicker around 500 rpm, sitting at stop light, with hot bike. Starts doing it in 70 degree temps, time for an oil change.


Bob, Lifetime bike: '71 T120R, bought in '71 at Ken Heanes, England.
Re: Oil pressure at idle when hot?
#126674 10/22/07 4:37 pm
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Quote
Originally posted by GeeMan614:
OK, I misread the info, but what is normal or good pressure at idle when engine is hot?
Gee Whiz -
There is no stated oil pressure for idle simply because there are too many contributing factors. What you really want to see is between 60 & 80 psi at road speeds (2500 RPM +) when the oil is warm. If you have that, then you will (and here's where the contributing factors start to creep in) probably have sufficient oil pressure at idle.

Contributing factors include:
• Oil weight
• Length of time the oil has been in service
• Type of oil (mineral or syn)
• Ambient temp
• Case temp
• Oil temp
• Age of the crankshaft oil seal
• Condition, type and year of the OPRV
• Condition of the oil pump

And others. I place condition of the oil pump last because since 1966, I have only seen 1 or 2 "bad" oil pumps. They simply do not wear out unless the drive block explodes or a huge piece of metal gets in there and starts gouging. A lot of people replace them, but only as an excuse to spend money.


Quote
Originally posted by GeeMan614:
I think I need a new pump!
This is like saying, "There's no more beer in my glass, therefore there must be an invisible hole. So I need a new beer glass." Why don't you try starting with the obvious high wear item, namely the oil seal. Oil seals wear out, they get hard with age and loose their resilience, they also pop out of the timing cover on occasion. And seeing how the oil seal is ~$90 lower in cost, wouldn't it also be the most economical place to start?

:bigt:


Don't hide 'em, Ride 'em !!

RF Whatley
Cornelia, GA
Re: Oil pressure at idle when hot?
#126675 10/23/07 1:12 pm
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The brand and internal construction (steel backing) of the oil seal that feeds the crank can be problematic.

Also, someone could have over tightened the Oil Pressure relief Valve and distorted it. This can cause it to stick open and result in low oil pressure. You have two chances to perform this.

Is the pressure low through out the rpm range?
John


Re: Oil pressure at idle when hot?
#126676 10/23/07 1:44 pm
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Quote
Thank you for the replies, My pressure is about 5 lbs at idle when hot ( half hour of running). I think I need a new pump!
may want to try a new oil preasure gauge before getting too worried..
I`ve went through a couple of them over the years..both times, my gauge was reading way lower then my actual preasure..threw a new gauge on..and everything was fine..

Re: Oil pressure at idle when hot?
#126677 10/23/07 3:24 pm
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I might be in the same boat as G-Man, so see if this throws some light on the subject. I have a newly restored '69 Bonnie, less than 1000 miles. My brother has a newly restored '68 Bonnie, less than 800 miles. Both engines were completely rebuilt and are running on 30W-non detergent oil for their break in. Using a new oil guage I am getting the following readings:

Cold Start: 55psi
Idle: 30psi
2000rpm: 55psi
3000rpm: 60psi

After a 15 mile run:
Idle: 5psi
2000rpm: 13psi
3000rpm: 40psi
4000rpm: 50psi

The figures are the same for both bikes ('68 & '69). We both live in S. Florida and these reading were identical two months prior. Outside temp is hot (85 to 90 degrees), sunny, and humid as hell. I've been told that when we change to normal oil the oil pressure will increase to more normal range. I recently changed the crankshaft oil seal (to be on the safe side) and checked the pump. Everything looks fine. I might worry more if just one of the bikes had such low readings, but both bikes, rebuilt by different "experts" having the same readings under the same conditions, I'm hoping I have nothing to worry about. Although I worry every time that red light flickers at a warmed up idle, I'm hope everything is cool. What do you guys think?

Re: Oil pressure at idle when hot?
#126678 10/23/07 4:24 pm
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Loafer -
I remember seeing photos of those two immaculately restored bikes. Beautiful examples.

IMHO, your bikes suffer from item #1 from my list, your oil is too thin for the South Florida ambients. If you utterly refuse to break-in a bike with a multi-grade oil, then I suppose 30W was a good choice. But certainly after 200 or 300 miles that should come out.

I would swap both bikes over to 20W50 "motorcycle oil" ASAP. I think you'll be pleasantly surprised to see your oil pressure magically lifted into the "normal" range. This will be the "proof" of the remedy.

After several thousand miles, you both might both consider a synthetic such as 20W50 Mobile-1 for V-twins, which will keep its pressure at much higher temps, something you'll need in your locale.

Hope this helps! :bigt:


Don't hide 'em, Ride 'em !!

RF Whatley
Cornelia, GA
Re: Oil pressure at idle when hot?
#126679 10/24/07 12:58 am
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Bionic: This sounds exactly like my situation. Rebuilt motor about 600 miles on it, oil pressure has be low since day one? New oil seal and two rebuilt oil pumps, 20W-50 still didn't help mine. Pressure at speed is around 45lbs but at idle about 5 or less. I am not the sharpest tool in the shed but this is my 3rd rebuild, the other two are running great with no problems but this one just doen't want to co-operate, it also smokes on the right side (sitting on bike)but that is another thread for later?


Cliff Ginger
71 Bonneville 650RR?
73 Bonneville 750 (sold)
73 Trident
Re: Oil pressure at idle when hot?
#126680 10/24/07 2:48 am
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Quote
Originally posted by GeeMan614:
Bionic: This sounds exactly like my situation. Rebuilt motor about 600 miles on it, oil pressure has be low since day one? New oil seal and two rebuilt oil pumps, 20W-50 still didn't help mine. Pressure at speed is around 45lbs but at idle about 5 or less. I am not the sharpest tool in the shed but this is my 3rd rebuild, the other two are running great with no problems but this one just doesn't want to co-operate
Mr. Tool -
The prudent person might want to work their way down the list I left previously and note that the only mechanical item you haven't changed is the OPRV. The pump makes the pressure, the seal and rod bearings contain the pressure, but the OPRV is actually what "sets" the pressure.

Why not simply screw one of the other OPRV into the questionable bike for 2 minutes. You might just be surprised.

:bigt:


Don't hide 'em, Ride 'em !!

RF Whatley
Cornelia, GA
Re: Oil pressure at idle when hot?
#126681 10/24/07 7:16 pm
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RF, I have replaced the spring in the unit and cleaned it out. You think a whole new unit might be in order?


Cliff Ginger
71 Bonneville 650RR?
73 Bonneville 750 (sold)
73 Trident
Re: Oil pressure at idle when hot?
#126682 10/24/07 10:48 pm
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New oil seal?

Brand and did you put it in backwards?

We just had a dealer do this, that is put it in backwards.

Sounds just like his symptoms!

john


Re: Oil pressure at idle when hot?
#126683 10/25/07 12:39 am
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John, this is my second seal but I could still be backwards? What brand would you recommend and where can I get it? I need to order some other parts for another bike anyway.

Thanks


Cliff Ginger
71 Bonneville 650RR?
73 Bonneville 750 (sold)
73 Trident
Re: Oil pressure at idle when hot?
#126684 10/25/07 12:50 am
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The seal in the cover goes in with the spring side facing the cover,facing away from the engine.
Pioneer is the brand that has be recommended over and over here but I've yet to see a supplier mentioned.


When given the choice between two evils I picked the one I haven't tried before
Re: Oil pressure at idle when hot?
#126685 10/25/07 1:54 am
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Gee Whiz -
An easier rule of thumb for me to remember is that the spring always goes towards the oil you're trying to control. In the case of the points, the oil seal spring goes towards the cam gear. In the case of the crankshaft, the oil seal spring gets installed into the timing cover oil gallery. When both seals are installed in the timing cover they face opposite directions. That trips up a lot of people.

Yes, OPRV bodies can be bad, springs can get sagged out, and people can install the wrong spring. In the case of my 1966 (which had never been tampered with) the dome nut on the end had missed a machining step. The well for the spring was not machined into the dome and the spring was consequently being compressed an extra 1/10 of an inch. It was running oil pressures well over 100 psi.

And this is why you always take the oil pressure reading on a bike that's new to you.

:bigt:


Don't hide 'em, Ride 'em !!

RF Whatley
Cornelia, GA
Re: Oil pressure at idle when hot?
#126686 10/25/07 2:32 am
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Hi, I have a 1970 bsa A65 lightning. I had low oil pressure # 7 /8 lbs. at idle. I check oil pump installed on engine case, i found it leaking between pump and gaskit, you may be loosing oil pressure there, also, on the oil pressue valve i put a new one ,new high output oil pump (SRM) Now i got 60 lbs. at start up , hot 45 lbs , idle 32 lbs.And returned oil to Day tank full stream flow. Engine sounds like it ready to run. Thanks Rv


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