Was riding the last to days and suddenly the bike started backfiring. It idles fine, starts up fine, rides quite smooth but just seems to backfire when im either off the throttle or feathering it at.
Couple of things to note
1) S2R 800 2005 - almost 31k miles
2) I replaced the fuel filter has been replaced at 25k
3) I replaced the spark plugs at 29k - NGR Iridiums
4) Oil was recently changed at 30k
Now, here where I need some DMF assistance. I started poking around the vertical head and noticed something odd. Id looked like there was a hole in the cylinder head. I'm wondering if this is normal as just a casting error or whether I really have a big problem.
Im attached really high res photos so you can see what I'm talking about. Also I'm attaching photos of the spark plugs for your evaluation
Can someone with an S2R 800 look at their bike and see if they have the same goofy looking hole?
Also take a look at the plugs and let me know if you guys see anything out of the ordindary.
(http://s3.postimage.org/z34a92zs9/DMF_S2_R_Vertical_Head_01.jpg)
CLICK HERE FOR ULTRA HI-RES IMAGE OF THIS PHOTO (http://postimage.org/image/36mustays/full/)
(http://s3.postimage.org/kwomoxdwz/DMF_S2_R_Vertical_Head_02.jpg)
CLICK HERE FOR ULTRA HI-RES IMAGE OF THIS PHOTO (http://postimage.org/image/36my3vzyc/full/)
HORIZONTAL CYLINDER SPARK PLUG
(http://s3.postimage.org/6q8xh8fh6/Horizontal_Spark_Plug.jpg)
CLICK HERE FOR ULTRA HI-RES IMAGE OF THIS PHOTO (http://postimage.org/image/36mzrfcg4/full/)
VERTICAL CYLINDER SPARK PLUG
(http://s3.postimage.org/rzwn35kre/Vertical_Spark_Plug.jpg)
CLICK HERE FOR ULTRA HI-RES IMAGE OF THIS PHOTO (http://postimage.org/image/36n32i1fo/full/)
Plugs look somewhere between fine and lean.
Lean makes bikes pop, doesn't it?
Maybe reverse mods to see if they contribute/create the pops.....
Here's my hole :o I'm guessing it's in between fins?
(http://i329.photobucket.com/albums/l394/stopintime/005.jpg)
Whew..good to know that hole is normal..
Thats the problem. I havent had any popping for almost 6000 miles. Pods have been for 29k. I'm going to check the valve and see If they need adjusting again.
Quote from: Carbon 14 on July 18, 2011, 08:00:37 AM
Your spark plugs are carboned ALL the way up the threads. That doesn't look right to me.
I just assumed the first one or two threads do stick into the combustion chamber someone correct me if I'm wrong. I'm really not sure about it.
The rest of the treads arent really carbon. I have a habit of applying copper anti sieze on the sparkplug threads. I dont know if its required but I've noticed that the heat cycling tends to fuse the threads together making it difficult to unscrew the plug. I decided to err or the side of caution than to risk stripping the threads on the head (even though I always torque it to spec).
The residual carbonation might just be the anti sieze compound burning on the threads.I don't know if its meant to be at such a high temperature but it stlll seems to make a noticible difference. I don't hear that scary pop anymore from the threads cracking loose when I try to remove the plugs.
What model number plugs are those?
What all engine mods do you have?
Backfiring of that kind is generally due to a lean condition.
A suddenly occurring lean condition is usually an air leak.
Also possible that you've blown one of the exhaust gaskets, that can lead to backfiring also.
Those plugs look on the lean side.
TPO beast intakes
Boomtube exhaust,
I have dyno'd the bike w/ an advanced map (cylinder specific) generated for my powercommander III.
DCPR8EIX NGK's for the plugs.
I checked the head connections and they arent leaking anything.
I still have to check the valves but I've dialed them in 6k ago. (Zero closer torelance). I've got MBP collets in there so I havent had any major clearance changes for almost 10k
Belts were replaced at 24k when I did my last adjustment.
Nichols breather routed to the back seat.
NO new engine mods have been made since I installaed my boomtubes back at 24k. Beast intake was installed when the ODO had 1k on it.
I replaced the battery for the first time 4 months ago but the bike's been running fine for 4k with the shorai installed.
Assuming you've removed the charcoal canister... how did you plug the fittings in the manifolds?
threaded stainless metric socket head cap screws
Have you checked your exhaust system. Look for signs of a leak. Check the nuts that hold you system in place at the head. They could have worked their way loose. The gasket at the head could also be the problem. I've found exhaust leaks causing my bikes to backfire several times. The repeated heating and cooling of your exhaust can caused a localized and premature failure.
Quote from: EEL on July 18, 2011, 01:33:56 PM
threaded stainless metric socket head cap screws
Spoilsport. [laugh]
Have you checked that the PCIII didn't lose the map?
Quote from: akmnstr on July 18, 2011, 02:06:57 PM
Have you checked your exhaust system. Look for signs of a leak. Check the nuts that hold you system in place at the head. They could have worked their way loose. The gasket at the head could also be the problem. I've found exhaust leaks causing my bikes to backfire several times. The repeated heating and cooling of your exhaust can caused a localized and premature failure.
+1...my top cylinder bolts come loose every now and then...backfires when engine-braking.
Remove the seat and come straight at the bolts from the rear with an extended ratchet.
Head connections are fine. I can feed a very small puff coming out the vertical cylinder head connection but thats only when I rev the piss out of it. Its definitely better than the stock ceramic gasket setup I had stock.
I'll upload the map again into the PCIII. I got a cheapo dcpr8e standard plug. gapped it and threw in the the bike to see if maybe the iridium head was all jacked up. going to take it for a quick spin to see what happens.
Quote from: EEL on July 18, 2011, 06:18:23 PM
Head connections are fine. I can feed a very small puff coming out the vertical cylinder head connection but thats only when I rev the piss out of it.
?It doesn't take much of a leak...(one) symptom is if it backfires during decel/engine braking
You're running a much less restrictive exhaust with no cat or any emissions controls and you're wondering why it's backfiring on decel? Embrace it!
I'm the type of person that doesnt accept that a mod is causing a problem after 6000 miles of not causing a problem...
I may have tracked down the problem. we shall see..the PCIII isnt "communicating" properly. I'm trying to turn it on and it wont accept commands. Sometimes it works and then just stops communicating and the green led just turns off. Battery is fresh so I know its not that. If its crapped out on me, it might explain the issue. i've had it for 7 years so (was on my old M800 before my S2R 800).
Sorry, didn't realize that you'd been riding the same setup for 6000 miles with no problem. Was kinda confusing. Anyways, good luck. Sounds like the PCIII might have died on you. It's exhibiting symptoms of an S2R running a stock ECU with pipes.
Quote from: $Lindz$ on July 18, 2011, 08:25:32 PM
You're running a much less restrictive exhaust with no cat or any emissions controls and you're wondering why it's backfiring on decel? Embrace it!
Just because you have increased your flow through the engine should you expect backfiring. Proper fueling will eliminate a backfiring problem provided it is not sucking in air through an intake or exhaust leak.