ThumperPaul wrote on 07/16/24 at 14:19:41:


I don't know the cause of the reduced temperature - but DragBikeMike experienced a temperature reduction as well when he installed the first Wiseco Flat Top piston in his bike.  He also reported a dramatic increase in mpg.

I am using the rest of the 30 weight oil - the 10W-40 break-in oil will arrive in a few days.  With a proper pressure gauge the oil pressure is fine with the 30 weight.  I may need the larger bleed jet when I go to the heavier weight oil.

The stock Savage may not have "great" oil supply as built - but it is certainly adequate.  Youzguyz put 160,000 miles on his bike with the stock oil system.....the only thing that was worn beyond limits was the valve guides.  Use good oil, don't idle the bike on the sidestand, don't lower your idle speed below 1,100 rpm - and you will be fine.

"I currently have the #102 bypass jet installed - I will put the #120 back in and see if I can get the pressures down a little bit."


With 50 weight oil at normal operating temp, you can expect about a 9 psi drop across the filter at 4000 rpm.  So, if your gage in the filter cover read 20 the actual pressure at the cylinder head would be about 11.  With 40 weight oil I expect it would be a couple of psi less (like 18 at the filter and 9 at the cylinder head).  

I measure my oil pressure at the cylinder head.  That's the only place on the engine where the pressure actually counts.  It's the only portion of the engine that uses plain bearings (i.e. cam bearings).  But I think you can assume that the system from one engine to another will behave about the same.  Let's be bold and assume you actually have a drop of 7 psi across your oil filter (40 weight oil).  If you can maintain 17 psi on your gage at 4000 rpm at normal operating temp, then you should have approximately 10 psi at the cylinder head.  That should work pretty good.

Of course, the best way is to eliminate the guess work.  That requires a gage installed at the cylinder head.

I think the 2 psi reduction in pressure due to the 40 weight vs the 50 weight is pretty close.  I just dumped my Rotella (using it for break in) and replaced with 50 weight.  Pressure bumped up right around 2 psi (from 10 psi  to 12 psi  at 4K).

Since you are not measuring pressure at the cylinder head (the most critical data point), I think it is safe to assume that at 4000 rpm your pump discharge pressure (measured at the filter housing) will be about 7 psi higher than the cylinder head.  So, if you want 10 psi at the cylinder head adjust your bleed orifice to achieve 17 psi at the filter housing.  That would be at 4000 rpm and oil at normal operating temp (200 F).

   

Paul, that "10 psi" you are talking about is with a set of high-speed drive gears.  With stock oil pump drive gears, the oil pressure to the head is only about 5 or 6 psi at 4000 rpm.  At idle it's "ZERO".  Those values are with 50 weight oil.  With 40 weight it's even less.  Given the recent weather reports, I would say that Mobil 1 V-Twin 20W-50 Synthetic would be an excellent option.

I am chasing down a very small oil leak.  On a 30 mile ride I will have 4 or 5 small drips on the top of the starter motor or and the metal cover plate just behind the starter.  The top end is dry - it appears the oil is coming from the top of the clutch cover and getting blown down the bottom of the cylinder - then the wind catches it and blows it behind the cylinder.

In an effort to confirm it - I sprayed the top of the clutch cover with the cheapest can of spray foot powder I could find (evidently baby powder is not made in a spray).

NOTE:  The stainless screws have stainless washers - I believe they may not always seal properly at the 3 locations with the sealing washers with the rubber on the inside.....so I am removing the stainless washers at those locations.

I am still chasing down the minor oil leak.

I took the clutch cover off again....and I removed the clutch lever and the oil window, and then scrubbed it clean.

I used my "cheap" die pen to mark the gasket surface.

After a bit of scuffing the clutch cover around - I found a bit of a warp right where the leak is.  I continued sanding until it was gone and all the die was removed.

I then reinstalled it with the Suzuki gasket with the steel interior, and I used a very thin wipe of Suzukibond on the sealing surface where the oil passage is.

I had to go out of town and it has been sitting for a couple of days - I will likely get a chance to fire it up and see if the leak has been solved.

Very smart, Dave!  What I want to know is how it went from no leaks before the piston swap to discovering warpage with a leak?  Did the old gasket just do a sensation job of filling in the warped area of the mating surface?