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General Category >> Rubber Side Down! >> Checking Health of Oiling System?
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Message started by Axman88 on 02/24/26 at 08:32:12

Title: Checking Health of Oiling System?
Post by Axman88 on 02/24/26 at 08:32:12

I tried to search this topic, but wasn't able to come up with anything, either here, or in a general Google search. I did see some pictures of Savages where an oil pressure gauge had been hacked in, but couldn't see any details.

On another thumper, (Royal Enfield 500), I could run with the valve covers off and observe flow to the rocker arms, as a simple assessment of circulation. And, I could remove a fitting and tap in a gauge to measure oil pressure to the bottom end.

Still haven't put many miles on my machine. Not experiencing any issues, but I did find evidence that somebody had the head off, so it seems prudent to probe a little deeper and make sure there's no ticking time bombs. Perhaps a member has some idea of a technique that might work on my '05 S40 to check oil pressure and flow. What can I do to assess the health of my oiling system on my Suzuki?

Title: Re: Checking Health of Oiling System?
Post by Dave on 02/24/26 at 14:36:20

The oiling system does not have a lot of flow or pressure. The bottom end has bearings and they don't require a lot of oil. The cam and rockers need oil - and it has to be a good oil with a minimum of 1,000 ppm of ZDDP. (Like Shell Rotella T).

It is important to keep your idle speed no lower than 1,100 rpm, and do not let the engine idle while leaned over on the sidestand, as it causes the uphill exhaust rocker and cam lobe to get starved for oil. Do not let the engine idle for extended periods of time.....like somebody starting the bike in the winter to get the battery charged.

One way to see how your oil system is doing is to start the bike up and run it for a half a minute - then remove the front valve inspection cap and look inside and see if things are oily.

I have adapted a temporary pressure gauge in a spare oil filter cover, and just recently plumbed in a temporary fitting into the head cover. I don't plan on using these permanently - they are there just so I can see what is going on with the stock oil pump gears.....and the overdrive gears I made using DragBikeMike's design.

Title: Re: Checking Health of Oiling System?
Post by Dave on 02/24/26 at 16:35:33

Another source of access to oil pressure is using one of the two threaded plugs at the right front bottom of the engine.

You could buy an adapter that has matching threads and a pipe tap hole. You likely don't have room for a gauge in that location - but you could use tubing and a remote gauge.

Title: Re: Checking Health of Oiling System?
Post by Axman88 on 02/25/26 at 07:45:08

Thanks for your responses.

Visual inspection, via the valve adjustment ports sounds like a good idea. I think I'll see what happens when I try removing a cover and peeking inside after the engine is warmed up and running.

A port is just what I'm looking for. I only want to temporarily check oil pressure, and baseline oil pressure, while running "on the bench". Are you sure those threaded holes access pressurized points in the system? If so, where in the system are they located, hydraulically?

One challenge is that I don't have a factory manual yet. I am working from the Clymers manual only at this point, and it doesn't have a diagram of the oiling system. I do recall reading through an excellent analysis of the oiling system, probably here on this forum, but I'm having a hard time finding that thread again.

I do have a factory diagram for my Suzuki GZ250, (which I attached) and from what I've seen, the LS650 engine's architecture looks very similar. I wonder if you, or any member can confirm that the oiling system has the same general architecture, or note what the lube system differences are from GZ250 to LS650, or perhaps even post the correct diagram?

Title: Re: Checking Health of Oiling System?
Post by Dave on 02/25/26 at 15:56:19

Maybe this in the Tech Section will help.

http://suzukisavage.com/cgi-bin/YaBB.pl?board=tech;action=display;num=1151246239

Title: Re: Checking Health of Oiling System?
Post by DragBikeMike on 02/25/26 at 17:39:05

The GZ250 oil flow diagram you posted is generally the same as the LS650, but the diagram does not show the source of oil for the main bearings. The main bearings get their lubrication from the camshaft. The drain oil from the cylinder head provides the lubrication for the left-hand and right-hand main bearings.

This old post provides a very detailed description of the oil system. I think you will find it useful. BTW, I don't recommend that you remove the valve covers with the engine running. It's very messy. The best way to evaluate your oil pressure is to install a gage. I personally like the left-hand side of the head cover. Tapping into that location provides the most meanigful information. Normal pressure will be about zero at idle and 6 psi at 4000 rpm with oil at normal operating temp (200F).

http://suzukisavage.com/cgi-bin/YaBB.pl?num=1695617698

Good luck.

Title: Re: Checking Health of Oiling System?
Post by Axman88 on 02/26/26 at 16:40:23

Thanks for the responses guys,

Dave, it appears from that diagram in the other thread, that the ports you mentioned are in the gallery directly fed by the oil pump. That's great, thanks!

DragBikeMike, thanks for the link to your thread. That's what I recall seeing previously, appreciate your creating it and directly me back to it. I hear what you say about opening up the valve cover during running. I guess the cams will be slapping the pool under the camshaft, and slinging oil out vigorously in all directions. I'll go through your oiling system analysis and see if any other bright ideas pop into my head, then continue discussion there, since it's both recent and still alive.

Title: Re: Checking Health of Oiling System?
Post by Dave on 02/27/26 at 03:00:49

The stock oiling system is very reliable and I cannot recall anyone having a failure that was not related to improper assembly. Failure mode is when folks remove the clutch and the drive pin drops out of the gear on the back of the clutch.....and then the pump doesn't work anymore!

The other major failure(s) occurs when folks use oil with too little ZDDP and the cam/rockers wear out - or when folks let the bike idle while on the sidestand, or when the idle speed is set too low.

In 2005 the rocker warms were updated with a brazed on hardened pad, and these are more durable that the previous rockers that were all made from the same material.