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Message started by LANCER on 03/30/15 at 17:37:27

Title: OUCH
Post by LANCER on 03/30/15 at 17:37:27

Just sitting for extended periods of time without being able to run seems to have stuck a piston in the cylinder, leading to BAD things.

Michael, some of the things we talked about causing the engine knock was either the counter balancer or maybe piston slap...here it is.

I am still going to pull the cases apart just to double check the balancer.

http://images1.snapfish.com/232323232%7Ffp93232%3Euqcshlukaxroqdfv3%3B7%3A4%3Enu%3D323%3A%3E639%3E697%3EWSNRCG%3D3763%3C%3A%3B33%3B339nu0mrj

http://images1.snapfish.com/232323232%7Ffp93232%3Euqcshlukaxroqdfv36%3A57%3Enu%3D323%3A%3E639%3E697%3EWSNRCG%3D3763%3C%3A7%3A5%3B339nu0mrj

Title: Re: OUCH
Post by Kris01 on 03/30/15 at 17:52:23

Aaaa, it'll buff out! :D

Title: Re: OUCH
Post by justin_o_guy2 on 03/30/15 at 18:08:12

Bummer,dude.

Title: Re: OUCH
Post by verslagen1 on 03/30/15 at 20:33:47

there's not much to the balancer.
and both bearings are visible to the outside of the case.
although the stator side is a bit hidden.
clutch side, just take off the bolt and you should be able to get a good look at it.

I wonder if it's an issue with the wiseco pistons :-?

Title: Re: OUCH
Post by Dave on 03/31/15 at 03:17:31

Well it looks like there is a rust mark in the cylinder where the piston sat while the engine was in hibernation.

Not sure what to say about the damage to the skirt....it appears to to be a "not enough oil" or "got too hot and the piston got too big for the cylinder" symptom. The rings appear to be free...which normally isn't the case when an engine is overheated at cruising speeds (it appears the oil ring may be stuck).

If you asked me what happened and I only got to look at these 2 photos....my guess would be the owner let the bike sit for a long time and moisture built up in the crankcase and rusted the bottom ring to the cylinder. Then got it running and let it sit and idle for an extended period until it overheated. There isn't much oil being pumped through the engine at idle speeds, and even less cooling going on when the engine is sitting on the kick stand at idle. The engine obviously was ridden prior to being in storage.....as the cross hatch is worn off the cylinder where the rings travel, and that takes a good bit of miles to happen. (Maybe idled for an extended period with the enrichment knob pulled out.....and washed the oil off the cylinder wall?).

Why does everything look so dry and oil free....have the parts been cleaned off before the photos were taken?

Title: Re: OUCH
Post by LANCER on 03/31/15 at 06:15:05

The compression rings are free but the oil ring set is NOT. That sucker is SOLID in there.
Yep, rust mark around the cylinder where the piston sat for "some time" & "times & a 1/2 time" maybe.
I did wipe the cylinder wall and piston skirt with a shop towel before taking the photos to make it easier to see the detail.
Dave, these came out of REX.

I don't think this has to do with the Wiseco piston; more with extended periods of down time and too little oil on the piston/cylinder at start ups.
I was thinking that on one of those start ups as the piston broke free from its rusted position it was yanked sideways a bit and that was what led to the initial gouging at those two very prominent spots on the cylinder & piston. From there it was all just plain ugly.

But its a good thing I can just BUFF IT OUT & all is good ! ;D ;D

Kind of surprising he kept running as well as he did with it like this.

Title: Re: OUCH
Post by justin_o_guy2 on 03/31/15 at 06:24:20

Will you be looking at some ideas for ensuring such doesn't happen again?

Title: Re: OUCH
Post by Dave on 03/31/15 at 06:43:01

Well....I know you didn't let it sit and idle for too long - so my new guess would be that the piston was just too plain dry when it was started. I would guess that all that time sitting idle, being hauled cross country, and just sitting around allowed the oil to drain off the piston and cylinder wall...and most likely the gravity allowed the oil to drain out of the oil system and down into the sump. The damage most likely happened in the first few seconds after the engine fired....while the oil pump was trying to fill up the oil passages and oil filter.

I guess the best thing we should learn from this....is that we should spray some fogging oil or motor oil down the cylinder before we start our bikes after a long period of storage. (After seeing this I am going to do that to my bike before I fire it up....it has been sitting since last fall).

Title: Re: OUCH
Post by WD on 03/31/15 at 07:24:03

That would explain why it was giving you so many problems when you were here...

I need to ATF the CL100 and get it freed up again. If I ever get around to buying a new "carbon dater" for it. Sudco is kinda steep. Really steep for a bike that restored is worth about $10...

And that pic tells me that my 98 (turned over twice in the last 5 years) can be turned into a sign now. Case has been open to the atmosphere for at least 2 years with zero oil on board. Outside, in Dixie. Rings and transmission are probably solid rust at this point.

Title: Re: OUCH
Post by Dave on 03/31/15 at 10:24:14

Now you have a chance to do some Wossner piston testing!

I am curious why the Wossner has a "bench" at the bottom of the piston that the Wiseco does not have.

Title: Re: OUCH
Post by justin_o_guy2 on 03/31/15 at 10:29:27

If the wrist pin is right that bench is not needed. Increased piston weight,no function I can see.

Title: Re: OUCH
Post by verslagen1 on 03/31/15 at 10:44:22

The question would be what to do to prevent the damage.
It seems to be a moisture issue more than a lack of oil issue.

a squirt of oil and cycling the piston?
or change oil and go for a blast?

Title: Re: OUCH
Post by Dave on 03/31/15 at 10:50:24

Well I tend to believe these folks know what they are doing, and wouldn't put extra weight in a place it is not needed. If you look at images for most Wossner pistons...they don't have that bench on them, and this piston is unique. It could be that the bench provides stiffness, and they are able to make the piston thinner and lighter in other areas as a result.

I just have never used a piston that is shaped that way....and was curious if it makes any noticeable difference in power, vibration or noise.

Title: Re: OUCH
Post by justin_o_guy2 on 03/31/15 at 17:30:20

Yaknow, Dave, I've been watching you, and you're a smart guy. You read my post and you're not convinced. You offered some reasons I never considered. And, they are manufacturers,with mechanical engineers. So, I will come over and agree with you. And, FWIW, it's a Good Looking thing. I just don't understand the reason for the skirt. But they didn't do it just for fun, probably...

Title: Re: OUCH
Post by Boogieman on 03/31/15 at 19:01:28

Huh...now i have to know why there's a skirt on that piston.

Title: Re: OUCH
Post by WD on 03/31/15 at 23:02:34

Because performance style pistons tend to need the extra rigidity. The engine is going to run a touch hotter (usually), making the piston "grow" a bit more in operation than a stone stock version. You ought to see the skirts on a low compression forced induction piston... normally look like a 1930s or 40s flathead truck engine component.

Title: Re: OUCH
Post by Dave on 04/01/15 at 03:03:12

If you search Wossner Piston Image on google...you will get 100's of photos - but none have the bench in them nearly as wide as the piston for the DR650/LS650. Obviously the 2 stroke pistons are fully round, the 4 stroke pistons either have a full skirt...or some version of the thinner slipper skirt piston. A few have a reinforcement around the piston pin that looks similar to the bench on the LS650 piston - but none are as pronounced. Wonder if they would entertain a "Technical Question" about it? I sent them an email asking them about this unusual design.

And to make this more confusing.....this is the piston that fits the early DR650 and our LS650, and it weighs 371 grams.

Wossner for the DR650/LS650
http://i61.tinypic.com/xn8as8.jpg

And this is the piston that fits the later DR650SE with the 100mm bore, and they don't list a weight.
http://i60.tinypic.com/5lpg9i.jpg

Title: Re: OUCH
Post by LANCER on 04/01/15 at 06:48:20

The newer DR has a much shorter stroke; seems like that would affect the yankin' & bankin' of the piston in the bore.

Title: Re: OUCH
Post by Dave on 04/01/15 at 07:13:01

323F303D3B2C6C695E0 wrote:

The newer DR has a much shorter stroke; seems like that would affect the yankin' & bankin' of the piston in the bore.

It could be something to do with the long stroke and resulting rod angles. If you look at your piston/cylinder....the most severe scuffing occurred at the bottom of the stroke where the rod angle would be the greatest - and causing the piston to have the most pressure on the piston skirt.

Is this the big piston you were talking about WD?

Title: Re: OUCH
Post by Dave on 04/01/15 at 09:51:08

Well.....that Wossner design might not be the latest "hot ticket" design. This is what Wossner responded with:

Thank you for your email and questions. Wössner doesn't participate or post on bulletin boards or forums however please feel free to post my answers to your question(s) on your Suzuki Savage forum.

Our part numbers indicates what pistons were made first as a stocking part, the 8501 series would have been the first 4-stroke stocking piston then 8502 etc. The round skirt 97mm piston has not been updated to a newer style "slipper" style forging and without steady/increased sales they never got updated. On the 100mm bore pistons Wössner had a slipper style forging that the piston "laid out" pretty well on so that is why it was used. On many later 4-stroke pistons the Wössner family heavily invested in more and more dedicated lightweight forgings as the business and demand grew.

So....we have an old style engine..and the early DR650 and LS650 owners just aren't creating a big demand for the newest performance piston styles.....and the market doesn't support the design or tooling necessary to make it. That isn't to say the 97mm Wossner doesn't work well - it just may not be the ultimate piston that they could have made if the demand justified it.

Title: Re: OUCH
Post by Dave on 05/08/15 at 03:36:28

Lancer:

I have developed a recent concern about anyone dumping the oil and changing the oil filter on any bike that has been in storage for a while. My thought is that most of the oil has drained away from the piston and cylinder during storage - and then when you dump the oil and change the filter the oil system has to be refilled by the oil pump before any oil is actually pumped through the moving engine parts. The critical "dry start" time that everyone claims is when the most engine wear occurs......has now been extended a considerable length of time by the empty oil filter.

I believe we should warn folks "not" to change the oil and filter before they start up any bike that has not been run for a while. It would be better to start the bike and get it warm before doing an oil and filter change.

Do you remember if you changed the oil and filter before starting up REX following the dormant period?

Title: Re: OUCH
Post by Gary_in_NJ on 05/08/15 at 05:05:04

Dave,

Another way to prime the system would be to crank the starter for 10-15 seconds with the sparkplug cap removed (preferably with the sparkplug removed). While this will not pressurize the system, it will prime it.

Title: Re: OUCH
Post by jcstokes on 05/08/15 at 12:53:14

Agree with Gary In NJ, take the plug out and put a couple of drops of engine oil down the plug hole, replace the plug loose and crank a few times, or if you are scared of it starting, put in gear, very loose plug, ignition off and roll the bike around in gear, should get the bore oiled.

Title: Re: OUCH
Post by Dave on 05/08/15 at 13:05:02

424B5B5C47434D5B280 wrote:

The point I am trying to make......is don't make the situation worse by draining the oil and installing a new oil filter - which results in a dry system at start up. It would be better to start the bike with the old oil already in the bike.....then once it is warmed up and running again you can change the oil if you want to.

Adding some oil to the cylinder is a good idea if the bike has been dormant for a while, and running the engine starter a bit to prime the oil pump can help - and even changing the oil might be OK as long as you don't take the oil filter off the bike.

Title: Re: OUCH
Post by Jeff71 on 05/08/15 at 16:00:14

Could you just leave the decompression switch open a bit instead of pulling the plug? (You'd pull the coil wiring so it wouldn't start.)
Jeff

Title: Re: OUCH
Post by justin_o_guy2 on 05/08/15 at 16:57:14

Yeah, easier, quick er ,safer.