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General Category >> Rubber Side Down! >> Sludge on top of the piston at 10K
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Message started by roosky on 10/31/10 at 17:51:43

Title: Sludge on top of the piston at 10K
Post by roosky on 10/31/10 at 17:51:43

When I adjusted my valves for the first time (at 10K miles), I looked in the spark plug hole and noticed that the rod I was using to see the piston location had scraped some black gunk around where it was making contact. I was so focused on the valve adjustment that I didn't investigate more carefully. Later, I wondered if that sludge was normal or abnormal. Whaddaya dink?

Title: Re: Sludge on top of the piston at 10K
Post by Routy on 10/31/10 at 21:09:54

Sludge ????? Sure it wasn't just normal carbon buildup ?

Never fear, that does nothing more than up our compression
a bit, something that some of us spend hi dollars to acc :oomplish

Title: Re: Sludge on top of the piston at 10K
Post by Oldfeller on 11/01/10 at 17:20:12

Dry carbon build up is normal

Wet sludge is NOT normal

was this oily material? -- if so, then potentially BAD news

Has your engine been smoking any under sudden acceleration?

Title: Re: Sludge on top of the piston at 10K
Post by justin_o_guy2 on 11/02/10 at 06:33:16

Lets dont forget, the cavity the plug sits in gets sand & junk in it. Unless that gets blown out, then every time the plug gets pulled, theres crap just waiting to fall into the cylinder.

Title: Re: Sludge on top of the piston at 10K
Post by roosky on 11/02/10 at 14:06:44

I don't have much experience working with engines so I'm not sure if what I saw was normal or not. It seems it was not dry. Most likely oily. It wasn't very thick, but the tool left scrape marks in it. Since the bike runs rough (like it's not getting enough gas) at slow speeds (that's nothing recent) I discovered that it runs smoother if I pull the choke out a small amount (I've heard it's not a real "choke"), so sometimes I ride like that even when the engine's not cold anymore. Could that be causing a problem? Like running too rich or something?

I always clean the dirt off that falls next to the plug before I remove it, so I don't think it came from falling in the hole.

Thanks for your replies.

Roosky

Title: Re: Sludge on top of the piston at 10K
Post by Routy on 11/03/10 at 05:55:48

If it runs better w/ choke out, it is running lean not rich.
If it idles good and runs good everywhere except that slow speed surging, you likely would benefit from the "white spacer mod", or should I say thats what fixed my exact same problem.

If your bike runs good, no oil consumption, and no spark plug fouling, the carbon on the piston is normal,..... just pretend you didn't see it.

Title: Re: Sludge on top of the piston at 10K
Post by roosky on 11/07/10 at 17:21:43

Routy:

You brought up a point I've always wondered about: the WHITE SPACER. When I first bought the bike I noticed that most everyone removed the white space in order to (if I remember correctly) improve performance or something. I always wondered if the removal would reduce the gas mileage. One of the main reasons I bought the bike (remember gas prices in 2008?) was efficiency for my long commute. I posted a question about the WHITE SPACER and gas mileage but nobody replied. I'm willing to remove the spacer as long as my gas mileage doesn't suffer. I get from 60 to 64 mpg (I think I ride like an old lady) on my commute which is about 50 % rural and 50 % urban) and I don't want to do anything irreversible that would cost me in mpg.

Spark plug fouling: the plug looks more like whitish coloring than tan. I don't know if that's bad or OK.

As far as "pretending I didn't see it", I think that will work for me until spring (this is near the end of the riding season in Michigan) but after that I'll get more curious, take the plug out, and get my gun barrel light and really look at this "sludge" I mentioned. I was too focused on the valve adjustment to get curious about it when it would have been easier.

Roosky

Title: Re: Sludge on top of the piston at 10K
Post by Charon on 11/07/10 at 20:13:26

You can peruse my fuel mileages by clicking the "Fuelly" logo in my signature. There, you can see for yourself what the white spacer mod did to my fuel mileage. I didn't notice any change in performance, but the mileage got worse. I put the spacer back in. It may make a difference that I live at about 1800 feet altitude.

Title: Re: Sludge on top of the piston at 10K
Post by justin_o_guy2 on 11/07/10 at 22:19:43

You CAN get that sludge out.

Just gotta get a sludge hammer on it.

Title: Re: Sludge on top of the piston at 10K
Post by Routy on 11/08/10 at 08:55:58

If an engine is not running correctly,...w/ regards to lean and rich, it is not getting the best mpg. You cannot improve mpg by starving an engine for fuel....to the point of it surging or running rough.

On the other hand, if an engine is running correctly......defined as smoothly in all ranges, I believe it is getting about as good mpg as is possible, nor is there any noticeable performance gain to be had by modding the carb.
I just don't know why anyone would do the white spacer mod (same as raising the metering rod) if the engine is running smoothly in the low and midrange throttle.

I did the spacer mod because I had a surging at slow speed in the lower gears. Had this been years ago I would have raised the metering rod by moving a clip to the next slot. Trimming the white spacer did the same thing, and it corrected the low speed surging almost perfectly. I also now need less choke for a shorter time in cold weather. I did not notice any difference in fuel miliage, probably because its not using much fuel in the low speed range anyway.
My bike always did run good at hi and WOT range, and the one time plug check showed a nice tan white color. If however, I ever did a major open exhaust mod, and/or like to run a heavy throttle in hot weather, then and only then would I be modding main jet,....depending on other things like altitude.
Yep, I have always gotten near 50 mpg, but most my riding is in very hilly country. I also believe the large differences in mpg on this site, is the rider, not the motorcycle.

Title: Re: Sludge on top of the piston at 10K
Post by Oldfeller on 11/08/10 at 09:03:40

Amen, it's your right wrist that kills your gas mileage ....

Title: Re: Sludge on top of the piston at 10K
Post by roosky on 11/08/10 at 18:03:30

Thanks for the heads up about worse gas mileage after removing the spacer. I suspected that. I'll keep mine in, even though it does "surge" (runs haltingly) at lower speeds. Gas just passed $3/gal here in SE Michigan this week. It's starting to remind me of 2008. Problem is it's been in the 30s every morning lately. I used to ride down to 30 but I'm getting old and whimpy. I don't like to go below 40. The rut is on too and I counted 3 deer carcasses in the first 2 miles of my commute (in the morning dark). It makes me nervous. I have to drive through the municipality that has more deer/vehicle crashes than anywhere else in Michigan- 8 of them were fatal 2 years ago - all involved motorcycles.

BTW What is a metering rod?

I'll see if I can get a sludge hammer at Walmart.

Title: Re: Sludge on top of the piston at 10K
Post by Charon on 11/09/10 at 06:03:12

The "metering rod" is more commonly known as the "needle."

Title: Re: Sludge on top of the piston at 10K
Post by Routy on 11/09/10 at 08:19:50

I must be blind,... I never did find anything about the white spacer in Fuelly.
But I do question why the drastic differences in some of your mpg stats. Or did I miss the different conditions there too ?

537871627F7E100 wrote:

Title: Re: Sludge on top of the piston at 10K
Post by Charon on 11/09/10 at 08:28:04

You have to look back to early 2008. My mileage dropped from mid-fifties to high forties; then returned to mid-fifties when I put the spacer back in. And I did not completely remove the spacer. My spacer is approximately three 4-40 washers thick. I replaced the spacer with two washers, thus raising the needle by about the thickness of one 4-40 washer. The idea was to try the modification in increments, which would be easily reversible.

I do not always make remarks about the conditions under which I drive. Most riding, as with most of us, is local and doesn't change a lot. I can usually look at the locations where I fuelled and have a good idea what I was doing. The most extreme examples are under forty mpg running at 75 mph into the wind on I-80, and over 70 riding in the Rocky Mountain National Park at speeds of 35 - 40 mph. That's a range of nearly 2:1 on the same bike with the same rider.

Title: Re: Sludge on top of the piston at 10K
Post by bill67 on 11/09/10 at 08:36:29

0B20293A2726480 wrote:

The "metering rod" is more commonly known as the "needle."

jet needle

Title: Re: Sludge on top of the piston at 10K
Post by roosky on 11/09/10 at 18:30:01

Getting back to the first question, sludge on top of the piston, Oldfeller asked if the engine had been smoking during sudden acceleration and the answer is no. I think before I waste any more of your time with this question, I better take it apart and look in the hole more carefully and come up with an exact description of the "sludge", like maybe get some out on a Q-tip and smell it or taste it, or something. While I'm doing that, do you think I should open the valve gap for the exhaust .001 more than the intake? When I checked them that's the way it was so I made them both the same. Later I read that it's ok for the exhaust to be a tiny bit more open.

Title: Re: Sludge on top of the piston at 10K
Post by Oldfeller on 11/09/10 at 19:17:22

How about if you just go ahead and run it -- if you have no smoking and are using no oil you have no issue to be chasing.

It is possible for a recently started (just run for a minute) engine to make some condensation moisture (water is a combustion by-product) which would give you your "scraped mud" that you saw.

Run it, if you have any sort of issue it will show itself more clearly later on.

Title: Re: Sludge on top of the piston at 10K
Post by justin_o_guy2 on 11/09/10 at 19:33:11

Yep, dont sepnd time huntin a booger. If theres a problem, youll find it later.

Title: Re: Sludge on top of the piston at 10K
Post by Routy on 11/10/10 at 05:17:10

Exactly !
Now if the rod that you stick in the hole ever goes down to the crankshaft, then you have a problem ! ;D

Title: Re: Sludge on top of the piston at 10K
Post by bill67 on 11/10/10 at 05:26:45

I would put Sea Foam in the oil and gas to clean up the piston and engine.

Title: Re: Sludge on top of the piston at 10K
Post by Routy on 11/10/10 at 05:40:39

Not everything that Bill says is right,...like running an engine w/o oil :'(, but I can't knock the "seafoam"!
Something fixed the carb problem on my 50 hp 4 stroke Merc, and at 8 bucks a can, I'd like to think it was the seafoam.

272C29297372450 wrote:

I would put Sea Foam in the oil and gas to clean up the piston and engine.