Carbon build up....

[Chicknstripn]

I've torn my engine apart twice. Once at 37k and then 5k mile later due to a transmission issue. At 37k I noticed both pistons had quite a lot of carbon build up, however, I figured this was just normal for a bike with 37k. The second tear down, after only 5k on a brand new motor, the amount of carbon build up got me wondering if something is wrong with my set up. In both cases the front cylinder had less then the rear.
The amount of build up after 5k was enough to almost completely cover the top of both pistons and about the thickness of a heavy construction paper.
I run only 93 octane fuel and I'll occasionally add some fuel injection cleaner or an ounce of seafoam.
Any ideas as to why I'm seeing so much carbon build up?

 

[mrlogix]

what was the appearance of the carbon? satiny and hard or kind of soft and flat black like candle carbon. Carbon coating can happen very quickly (to a point) even in the best tuned engines and is normal. The additives that the petroleum companies put in the mixtures when blending summer and winter fuels can cause carbon build up (normal type-minimal thickness kind of hard and dry and a little satin shine). What did the plugs look like? You mention tearing the engine apart twice, did you rebuild the first time? New rings, Valve job?

 

[Cosworth]

What kind of tuning have you done? Heavy carbon is usually the result of a rich tune. Its not uncommon for these engines to build up pretty heavy carbon though...

 

[Tbone]

Any advice for getting and keeping the carbon out of the engine would be awesome as it appears to be common with the XB engines? Wonder if ethanol gas makes it worse? When I first got my 09 Uly it had 13K miles and the dealership somehow cleaned the carbon out of the engine. It pinged like crazy, really crazy, during the test ride and it made a huge difference to have it cleaned out.

 

[Cosworth]

Install a wideband and tune leaner.

You'll never get rid of all of it, but the closer to stoichometrically ideal the less carbon build up there will be.

 

[Chicknstripn]

First rebuild EVERYTHING on the top and bottom end was brand new. Only thing I reused was the transmission(big mistake) and the clutch.
The carbon build up does seem to be the "normal" type. Took a little bit of work with and old toothbrush and brake cleaner to remove it.
Plugs look slightly "hot". A slight burned looking ash if you will. Normal as far as I can tell. After first rebuild I switched to NGK dcpr9eix iridium plugs. Had the non iridiums first 37k.
I have a Buell race ECM. Bike is a 200712r. It is now a 1250 with cams and stag two head work. I've never tuned the ECM.
I'm sure tuning would greatly reduce the carbon build up.
I'll wrench on anything any day of the week but when it comes to messing with the electronics/ECM I get a little gun shy.
Thanks for the responses guys

 

[theMelvster6]

What cams? Definitely needs tuning with the combination of work you've done. I would suggest putting your timing back to stock, it'll probably like it better with cams, head work, and higher compression. Unless you feel confident enough to get some dyno time in to really tune the ignition. Other than that, hook up a wideband to it and do some data logging. With a wide band do some controlled throttle runs and monitor your AFRs and make a not where you are at on rpms and throttle position. Might be helpful to Mark your throttle at 1/4, 1/2, 3/4, and WOT so you can see if you are too rich or too lean in any specific cells on your fueling. Datalog and then adjust accordingly. With a hopped up motor a WB O2 sensor is a wise investment.

 

[UMDterp13]

Race kit/tuned bikes run rich. More carbon
have a very high mileage stock set of pistons which are just bronzed over from borderline good tune/lean I kept since the rings were almost seized to the piston & crank went bad.

Any race ECM/tuned motor I pull apart has more carbon than a stock ECM stock kit bike.

 

[Chicknstripn]

Would a wide band be a plug and play upgrade? Or does it require any additional "stuff"?
Timing was set at stock.
Will be once it's all back together.
Would love to get on a dyno and have the tuning done right. That might happen this spring.

 

[Cosworth]

If you got a kit such as the innovative mtx-l or spartan wideband youd have to wire it in, weld in the exhaust bung, and find a place to mount the gauge. So it'd take a bit of mechanical skill.

 

[Matteson]

When we tuned a buddys zx10r after cams(degreed), milled head, thinner hg we actually had to reduce fuel from the stock mapping. It was burning the fuel very efficiently with the race setup. Race setups vary obviously. Just something to think of. More fuel isn't always what's needed on a race motor.

 

[theMelvster6]

innovate stuff simulates a narrow band signal too. a lot of people do permanent install in place of the oem narrowband sensor. I put mine on a toggle switch to switch between narrowband and wideband back to the ecm. it helps greatly with datalogging and tuning.

 

[Cosworth]

So will the 14point7 stuff, comes out of canada but its a pretty nice product.

http://www.14point7.com/

 

[theMelvster6]

the nice thing about innovate is you can program the voltage output and skew your afr so it can target a richer closed loop. Instead of Stoich (14.7)...you can make it read 14.0 if you want. basically tricks the ecm into thinking its at stoich, but running richer if desired. I dont know if other brands do that, I'm not familiar.

 

[Chicknstripn]

You guys have me thinking. First thing I'm going to do if get up with Dean Adams about getting one of his full systems that have the headers already set up with O2 bungs on the front and rear cylinders. Depending on that price point, I'll start looking into what wide band set up to run with.
Since were on the tuning tangent, let me ask this; will a GOOD dyno tune negate the need for any type of wide band set up? Can I get good results on the dyno with a stock narrow band set up? If I remember correctly the ECMspy tuning guide says to disconnect the O2 sensor when dyno tuning.

 

[Cosworth]

Narrow band is useless when tuning, the bikes ECM uses it to determine is the bike is lean, fat or close enough to ideal. Kinda a yes no maybe....
Wide band is only good when tuning but not necessary when riding about, unless your force inducted in which its a good idea to make sure something hasn't gone wrong causing a lean condition which equals a melted piston or detonation.

If your taking it somewhere to have it tuned chances are they will have a AFR sniffer, which is adequate but from what ive seen isn't the end all since its so far downstream. I think Deans test mule exhaust had 02 bungs on each cylinder close to the exhaust port on the head to set both cylinders AFR

 

[Chicknstripn]

I think I've seen pics of said "test mule". Like I said, I'll probably contact Dean regarding an exhaust set up. With tax season being right around the corner, I have no reason NOT to throw more money at this bike!

 

[Chicknstripn]

Another carbon question... ....would it help reduce carbon build up to polish the top of the pistons?

 

[mrlogix]

a proper tune and reading the plugs will help more than polishing the piston domes. The carbon is unburnt hydrocarbons wether they are from fuel additives, oil blowby or improper tune

 

[Cosworth]

^ ding ding, you'll get build up either way. Polishing might resist the build-up for a little-while but it will build up no ifs ands or buts.