Hey guys. So my oil pressure got low riding back through the desert. Bout 115 degrees outside at the time rode the bike about 100miles with the low oil pressure. My Checked oil pressure and it was 3psi below what was needed. He also did a compression test on both cylinders and checked for damage all the valve train looked good, cylinders have no signs of damage.and oil had very minimal amount of metal. Upon checking the compression the rear cylinder was 12lbs lower than the front. We are replacing the oil pump and lifter with fueling parts. But I was wondering if I needed to worry about that 12lb variation. He said it could be the rings but he doesn't seem too worried about it said I should be fine after sorting the oil pressure

Bike is a fuel injected 88tc that recently got a se 95" big bore kit with flat tops and 204 cams

 

"3psi below what was needed"; what does that mean? Don't know that a 3psi drop in oil pressure with 115* ambient temps, particularly if running a synthetic oil, warrants pump or lifter replacement. I think you are spending unnecessarily but that's JMHO.

The rule of thump for compression variance between cylinders is that a variance of 10% is normal; more would indicate a possible problem. I would guess that your CCP (at sea level) would be 165-170psi in a 95" motor, stock head gasket and SE204 cams. If you are higher than sea level, say Denver at 5000' higher CCP would likely be in the 150psi range. In either case, a 12# variance is less than 10% so not to worry. Having said that, I would do a leak down test just to further check on the condition of the top end.

I don't believe you have an oil pressure issue which is not to say that a new pump won't increase oil pressure a bit, just saying that the HD vtwin doesn't rely on oil pressure but on volume. Further more, oil pressure has nothing to do with compression.......

 

Thanks for the reply good sir. I'm about as ignorant as it gets when it comes to motors. So a 10% difference is ok? Didn't know if my mechanic was just trying to bullshit me or not was my main concern. And I know the oil pressure and compression are not related but the whole reason I brought the bike in was because the oil pressure was low. And I was wondering if it caused some kind of damage resulting in a compression variance between the cylinders . Like I said I'm ignorant so I hear (12psi) variation and first thing I tho k is fml my motors ****ed

 

What makes you think you have an oil pressure problem? Why are you worried about oil pressure? What is your oil pressure at idle and at cruise? Are you running synthetic oil? If not what are you running? The OEM oil pump is more than adequate for a 95" motor with SE204 cams and stock compression. How many miles on the build?

The 10% variance is the generally accepted rule in the automotive industry. I would prefer not to see a 10% variance on a motor that I built but if I did, I wouldn't tear the motor down for that reason. I might run a leak down test to see if the variance was related to ring or valve seal just for future reference and you might want to do the same.

 

I am like djl in that I am a little confused. Do you have an oil pressure gauge on your bike or did the oil pressure light come on? As hot as it was, if you have a gauge that was reading a bit low, I would not be concerned enough to start tearing into things.

 

Your oil is gonna be pretty thin especially if you are running 20w-50 in that heat.
Straight 60w would be the ticket.
Most people including myself run 20w-50
Actually 80 degrees and above calls for 60w so I am guilty of neglecting my ride too.

 

All good advice here.

Did the bike have the proper amount of oil? When was the last time oil was changed.

I'd be skeptical of the guy just suggesting changing the Oil Pump (to some hi $$ aftermarket) without inspecting the Cam chest first...

Think about it, If the Pump was bad and you rode the bike for 100mi. in that heat, the engine would be fried.

If it actually needs replacement, the OE Pump / Plate is fine, spend the $$ difference on something else...

BTW, in my first hand experience with fueling, I will never purchase any of their products again!!!

 

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So you live in Vegas and ride @ times in 115 deg f temp?

Then you can benefit a lot from an ultracool oil cooler with twin elec thermostatically controlled cooling fans along with wards twin cooling fans (targets cooling heads & upper cyls) both at the same time on your bike .

Collective together they reduced oil temp 50deg f in extreme summer heat on my 09 hd.

And when you reduce oil temp 50deg f that also significantly reduces engine temp @ same time too.

Scott

 

do u sell these ultracool oil cooler with twin elec thermostatically controlled cooling fans along with wards twin cooling fans
or what? u sure push them

 

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w.t. Heck,not again!

I have no connection of any kind with any mfg's(oem or aftermarket parts/oil etc!) of an kind associated with motorcycels & or automotive vehicles either!

Maybe its about time you & the other paranoid guys on this site that comment on my posts with nothing but negative things and or think i have something to do with every frigging mfg's product i post thats worked great for me needs to get " your head out of your butt " & ,open your mind to realize what i am posting is true & not bs trying to do what?

" help guys posting heat related performance & comfort issues " because i simply want to pass along just how great the cooling setup i installed on my bike works that resulted in many improvements in engine perf & rider comfort & thats it!

I see plenty of other guys posting things they have done that helped their bikes with no backlash from the " peanut gallery " here but not me.

Most of the guys that respond to & or comment on my heat related posts seem to be very closed minded & pigheaded stating it's not needed & or wont be beneficial either not ever trying it.

And thats after they read the 5-6 great improvements obtained post reducing oil temp 50deg f (engine temp is sig reduced @ same time too!) in summer heat when they have absolutely no idea what they are talking about because they in fact " never tried it using the same 2 cooling mods i did" making them " totally full of bs ".