SuzukiSavage.com - Print Page

SuzukiSavage.com
/cgi-bin/YaBB.pl
General Category >> Rubber Side Down! >> Camshaft and follower wear and oil.
/cgi-bin/YaBB.pl?num=1434334435

Message started by gizzo on 06/14/15 at 19:13:44

Title: Camshaft and follower wear and oil.
Post by gizzo on 06/14/15 at 19:13:44

Pulled the rocker box off my ancient 1990 DR250 this am to fix an oil weep in the head/box joint. And also to check the 40,000km old timing chain. Since the architecture is pretty much identical to the Cabbage, just smaller, I thought I'd post up a couple pictures showing the wear on the cam lobes and followers. The cam lobes are pretty much as good as new. The follower pads, you can see the wear marks in the picture. Rubbing a finger over them, all I can feel is a difference in texture. Where the pads ride the lobes, the pad is smoother than the rest of the follower. With my fingernail I can't feel any difference between the "worn" and unworn parts. No step, groove, ledge or anything. Just the change in texture. This is in a 60,000km engine with no special treatment apart from timely oil changes (2500km) using any oil to hand -automotive, diesel or bike, I'm not fussy, and which has spent a good part of it's life north of 5000rpm.
I changed the timing chain many years ago, at 20,000km because that's what you did (was working on XR and TT 's at the time) but this one's done 40,000 and still looks fine. So I'm leaving it.
There's no point to my post, just showing ya'all. And kind of reinforces my belief that Savage valve train wears out because of poor manufacturing more than a lack of ZDDP. I'm not saying the Savage doesn't need zinc, mind, just that my DR with Flat Tappets doesn't. Early XR250 was a similar problem, saw a bunch of those worn out cams and followers.
Happy days :)

Title: Re: Camshaft and follower wear and oil.
Post by gizzo on 06/14/15 at 19:14:42

The other pic

Title: Re: Camshaft and follower wear and oil.
Post by Kris01 on 06/14/15 at 20:42:29

Looks good as new!

Out of curiosity, top pic, top cam lobe, there's a "parting line" on the lobe. Any idea what it may be? Manufacturing defect?

Title: Re: Camshaft and follower wear and oil.
Post by gizzo on 06/14/15 at 21:25:52

Nah, no idea. Is some kind of machining mark but its back together now so I can't go in and look ;)

Title: Re: Camshaft and follower wear and oil.
Post by Dave on 06/15/15 at 15:43:54

There are too many variables to jump to the conclusion that the Savage is not made as well as the DR250. Most likely the DR250 valves are smaller and the springs are likely not as strong.....and the lift may be smaller as well. The DR250 parts may not be under as much stress as the LSA650/S40 parts.

Title: Re: Camshaft and follower wear and oil.
Post by verslagen1 on 06/15/15 at 17:56:10

Comparing one result against many isn't the same.
One purchased new bike against many used bikes ain't the same.
One mechanic against many of various levels definitely ain't the same.

Title: Re: Camshaft and follower wear and oil.
Post by Kris01 on 06/15/15 at 18:25:26

605B5641505C47415A525F40330 wrote:

Most likely the DR250 valves are smaller and the springs are likely not as strong.....and the lift may be smaller as well.

http://suzukisavage.com/cgi-bin/YaBB.pl?num=1434328838/0#0
I hope I'm using specs from the right bike.

DR-Z250:
Valve diam. (int./exh.): 28.5 mm / 25.0 mm (1.12" / 0.98")
Valve spring tension: inner: 10.6-12.8 lbs; outer: 29.3-33.7 lbs
Cam lobe lift (int/exh): 35.32-35.36 mm / 35.22-35.26 mm

LS650:
Valve diam. (int./exh.): 33 mm / 28 mm (1.3" / 1.1")
Valve spring tension: inner: 15.2-18.7 lbs; outer: 36.2-41.4 lbs
Cam lobe lift (int/exh): 36.174-36.228mm / 36.419-36.473mm

I knew that link would come in handy! :D

Title: Re: Camshaft and follower wear and oil.
Post by gizzo on 06/15/15 at 20:09:49

4C5F4849565B5D5F540B3A0 wrote:

Comparing one result against many isn't the same.
One purchased new bike against many used bikes ain't the same.
One mechanic against many of various levels definitely ain't the same.

No doubt. I just put it up for interests sake.

Title: Re: Camshaft and follower wear and oil.
Post by Art Webb on 06/20/15 at 12:00:50

The Savage does have a known issue with oil pressure at idle speeds below 1k, who knows how many POs turned the Idle too low to get that 'thumper' sound
Still, I'll stick with rotella