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Oil Temp or Oil Pressure Gauge?

Started by 86FJNJ, July 23, 2025, 11:44:25 AM

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86FJNJ

I see RPM sells separate oil temperature and oil pressure gauges. Curious if anyone is running one and why? With the FJ being air cooled and me getting caught at some longer stoplights having the temp gauge would offer some entertainment but I'm not sure it adds much value. Where as the pressure gauge would alert me to an issue if the oil system failed but I'm not sure if that Should even be a concern, I'm not sure I've heard of people blowing their engines because the oil pump failed.

Curious on the groups thoughts since I'm not aware of a gauge that shows both oil temp and pressure so seems like have to pick.

1986 FJ1200 converted to Fuel Pump

Pat Conlon

Between the two I would opt for an oil temp gauge, not to be worried about high oil temps but to watch when my cold oil temp gets to the 180° safe zone before I start hammering on my engine.

I find it amazing how long I have to ride on the street before my oil properly warms up.

I lived 40 years in the low desert and I can imagine my summer oil temps exceeding 280-300°, but as long as I have air flow over the engine, all is well. It's the 117° days with stop and go traffic that's alarming.

Oil pressure is not an issue. The racers have found FJ 2 stage oil pump system to be remarkably robust. HSR has a supplemental oil line kit for the FJ engine that adds more oil volume to the cams. Broken cams from heat distortion seems to be a problem with the racers, but that's cooling airflow related, not oil related. 
1) Free Owners Manual download: https://tinyurl.com/fmsz7hk9
2) Don't store your FJ with E10 fuel https://tinyurl.com/3cjrfct5
3) Replace your old stock rubber brake lines.
4) Important items for the '84-87 FJ's:
Safety wire: https://tinyurl.com/99zp8ufh
Fuel line: https://tinyurl.com/bdff9bf3

Millietant

I wouldn't bother with either - FJ's don't fail due to overheating their oil, or due to oil pressure issues (pump failures).

If you fit one, it will only get you needlessly worried about the numbers you're reading from time to time.

I can imaging for some high level racers and for legend race cars, then there could be some merit in monitoring those, but on a street bike, just don't give yourself something else to worry about needlessly.
Dean

'89 FJ 1200 3CV - owned from new.
'89 FJ 1200 3CV - no engine, tank, seat....parts bike for the future.
'88 FJ 1200 3CV - complete runner 2024 resto project
'88 FJ 1200 3CV - became a race bike, no longer with us.
'86 FJ 1200 1TX - sold to my boss to finance the '89 3CV I still own.

86FJNJ

1986 FJ1200 converted to Fuel Pump

red

86FJNJ,

If I had to choose, I'd want to see oil temps, but I probably would have both, or neither.  At idle, FJ oil pressures can get to 10 PSI or maybe less, and most riders will panic over such low numbers.  It was always like that, but they just never knew.  Pat gives you good advice above, about oil temps.
Still, it's your call there.
Cheers,
Red

P.S. Life is too short, and health is too valuable, to ride on cheap parade-duty tires.

Pat Conlon

Yea....Dean brings up a good point, why the needless worry? I have to agree.


I think a TPMS would be more practical for safety reasons.
To be alerted to a slow leak could save you some excitement while at freeway speed.
1) Free Owners Manual download: https://tinyurl.com/fmsz7hk9
2) Don't store your FJ with E10 fuel https://tinyurl.com/3cjrfct5
3) Replace your old stock rubber brake lines.
4) Important items for the '84-87 FJ's:
Safety wire: https://tinyurl.com/99zp8ufh
Fuel line: https://tinyurl.com/bdff9bf3

Bozo

Good topic, some years ago I had the gear ident lever changed to a stronger version. I didn't notice that during clutch hub assembly the oil pump gear dogs were not engaged correctly (my excuse - my kawasaki's use a direct gear drive).

After a long ride the hub spun disengaging the oil pump gear dogs once in a blue moon causing my bike to seize, if only I had a pressure gauge all would've been avoided.

Lesson learnt never again.
First major bike in my life was a Mach III widow maker.
My Second permanent bike 1978 Z1R (owned since Dec 1977)
My Third permanent bike is the 89 FJ12 - nice and fast
Forth bike 89 FJ12 my totally standard workhorse
81 GPZ1100 hybrid - what a bike, built to sell but I can't part with it

Old Rider

I have installed a oil temp gauge.Most for fun and keep an eye if engine is overheating for some reason. It has an alarm beep that can be set .I set my at 110degree Celsius very very rarely it make the alarm go off even in hot summerdays.
The gauge readings goes up to 150 degree so oil temps seldom goes over that i think.
I have the sensor mounted in the oilcooler witch is a separate oilway out of the 2 way oilpump. after or before a ride it shows ambient temps because the oilcooler then is emty.On these picks from yesterday the the bike has idled for about 2 minutes and temp is only 88 .It takes very long time before engine reach
operating temps
:morning1:

86FJNJ

Thanks Old Rider, I have a slight paranoia that my engine might get too hot so I recently added the RPM oil cooler kit to help keep that under control a bit better than stock. With it being 95 degrees F here in NJ through the next month or so I was thinking seeing oil temps might be nice but based on group feedback and Pat's experience in Arizona I guess that is not a concern as long as I'm moving. I go get stuck at the occasional long light for a couple mins but that's about it. So with the group saying oil/engine temp and oil pressure is not an issue so I'll prob not proceed with that....

...might be time to stop upgrading the FJ and start saving up for next bike, I'd really like a modern sport tourer or adv bike like Vstrom 1050 (or maybe 800), Yamaha Tracer 9 or Triumph Tiger 900, something sporty with enough grunt and comfort for easy 2up riding and room for side luggage but still enough handling ability I can enjoy a spirited ride on my own, 95% on road with the occasional dirt road...something I can pick up used but clean with plenty of life left for under $10k...if anyone in the group has any two cents on such bikes I'm open to it, or maybe I should start a separate thread for that feedback.

1986 FJ1200 converted to Fuel Pump

Bones

I live in Queensland Australia where we get hot summers and Christmas time when all the toy runs start is at the start of the summer season. Toy runs are usually first/second gear affairs for miles and where the engine gets that hot from no airflow you can feel the heat burning your legs and see smoke emanating from it.

Worried about possible damage I fitted an oil temp gauge to monitor it and have seen temps in the years gone by around the 135deg Centigrade mark, I've been assured that the engine won't be harmed at those temps because race cars running these engines run hotter than that without any problems.

Normal temps while cruising sit around the 80deg C mark and as Pat has said it take s quite a while from cold to get up to normal temps before giving it the beans. Thats probably the reason why the majority of bikes don't have oil temp gauges fitted because owners would probably panic seeing temperatures that high.
93 fj1200
79 suzuki gt250x7


Too young to be old but old enough to know better.