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merv
10-10-2004, 09:07 PM
I have about 150 miles on my new 02 st2. I noticed that it backfires/exhaust pops every now and then. Is this normal?

Bong
10-11-2004, 01:28 PM
Merv, you may want to check the exhaust header pipes to ensure that the sensor fittings haven't come loose or fallen off. There is usually on on each cylinder header pipe. I had one come off and the engine was backfiring on deceleration. Good luck.

merv
10-12-2004, 01:44 PM
There aren't any sensors on the exhaust anywhere.

Bong
10-12-2004, 04:13 PM
Sorry, there aren't sensors - just the exhaust plugs the screw in. They are about 1/2" diameter, you can't miss them as they are right on the exhaust headers. If they come loose you will get an exhaust leak and backfiring. This may not be your problem, just wanted to point out that these came looses on my bike and caused similar symptoms you describe.

Two-Push
10-12-2004, 04:51 PM
I have about 150 miles on my new 02 st2. I noticed that it backfires/exhaust pops every now and then. Is this normal?

Is it doing it on declaration or all the time, sort of randomly? My S4 did that for a while as I backed off the throttle and we cleaned the plugs and sync'd the throttle bodies. Problem went away. Or, just take it out and give it an "Italian tune-up". No, wait...don't do that. Doesn't sound like a big deal. you may just be riding it a little too slow and fouling the plugs.

lll0228
10-12-2004, 07:40 PM
You may also be using too high octane in gas. Get down to 89 or even 87. The ST2 only runs at 10.3:1 compression (pretty low), with too high octane you will end up with a lot of unburnt gas at the exhaust. Just guessing.

Curt999
10-13-2004, 07:43 AM
I have about 150 miles on my new 02 st2. I noticed that it backfires/exhaust pops every now and then. Is this normal?

Backfiring on deceleration can mean it's running to lean. Do you have aftermarket exhaust on it? If aftermarket exhaust was put on the bike with out being tuned to them it is most likely running too lean. My 01 ST-2 did the exact same thing when I switched out the exhaust. If you have the means ducsea can tune it properly with an analyzer. If not you can get it pretty close at home, enough to stop the backfiring. I can give you some help if needed...

Curt

cpcumming
10-13-2004, 08:16 AM
I've had similar issues to Curt998's on my 01-ST2 when I put on new slip-ons. It burped/hiccuped on deceleration and it was in fact running too lean. Merv, is it stock exhasut?

Also, not to hijack the thread but Leo, interesting bit of info about the octane, I've never heard that before. I always put in 91 but I wonder if I should switch to 89...

merv
10-13-2004, 08:38 AM
Lol....I was staring at the plugs on the exhaust header wondering if I was missing a sensor. I have the stock exhaust and I do put super unleaded in it. It only does it every now and then in 2 different senarios. Sometimes when I am decelerating and sometimes when I throttle back up after completely letting off the throttle. It does run great, but I am taking it really easy on it until the first service, so like Two-Push said maybe I am not riding it hard enough. :scared10: