Here I am again. The S4 is making a lot of noise. I wear ear plugs all the time but decided not to on the way home from the eye doctor today. Holy hell. I'd hate me if I weren't me.
Here's the skinny:
Bike backfires a lot on decel. Very rapid and very loud. The bike will also pop and throw a fit just cruising along at around 4K. Finally, sometimes as I am coming to a stop, I'll pull the clutch and blip the throttle just out of habit and every once in a while I get a loud, hollow pop that sounds like it is coming from the intake.
Here are things that have or have not been done recently...
-Valves were adjusted
-Exhaust came on and off a few times. I reused the gaskets
Fueling issue? Exhaust leak? Nature of the bike?
Exhaust leak.
Either get new gaskets, or remove the exhaust and use sealer...
or both. ;D
You would have to suspect exhaust leaks with them having been on an off a few times. Then there's reusing the gaskets all those times. Thats where I'd start.
Oops, too slow. +1
if new gaskets doesnt cure it, I'd look into checking the ignition timing as well as testing the TPS.
leaky gaskets may cause some minor popping and un-smooth sounds, but they more than likely would never cause backfiring type popping, nor would leaky exhaust gaskets cause any type of popping from the intake (unless you bike has an o2 sensor and the exhaust leak is before the o2).
loud popping or backfiring out the exhaust is usually the result of ignition timing being too retarded, or using way too high of an octane of fuel, or tip-in enrichment/retard being too drastic from a bad TPS. check your plugs, if they're black after a long hot ride it could simply be that you're running too rich. rich burns colder and longer and often allows the combustion flamefront to continue out the exhaust when closing the throttle
food for thought
Quote from: ducpainter on July 10, 2012, 05:52:36 PM
Exhaust leak.
Either get new gaskets, or remove the exhaust and use sealer...
or both. ;D
I respectfully disagree. Sealer will only make it a PITA next time. New gaskets, new bolts. You can buy a BOX of copper self=locking exhaust bolts for around $8.95 from any Au-Ve-Co or WURTH dealer.
I'd also have your mixture checked. IIRC, popping on overrun/decel is a clue to too lean.
FWIW I was in exactly the same boat a few years back. I thought I needed new gaskets as well. I rode around, without fixing it, long enough that my valves came due again. I re did the valves and that fixed the issue. The clearances were a little off but nothing to write home about. That previous valve job was my first attempt so I'm sure I just screwed up the math.
It might be good to cover all bases and check the valves and replace the gaskets.
Quote from: dlearl476 on July 13, 2012, 09:54:46 AM
I respectfully disagree. Sealer will only make it a PITA next time. New gaskets, new bolts. You can buy a BOX of copper self=locking exhaust bolts for around $8.95 from any Au-Ve-Co or WURTH dealer.
I'd also have your mixture checked. IIRC, popping on overrun/decel is a clue to too lean.
I was thinking the gaskets at the slip joints that some 4V bikes use.
Not at the head. Those gaskets should be replaced every time.
All good info [thumbsup]
I'll be checking the plugs and such.
Is there anything I can do with the fueling without getting a power commander?
The PC's aren't too terribly expensive so it might be worth my while to look into one.
Valves should be good. I just spent all winter having fun with it
Quote from: ducpainter on July 14, 2012, 06:24:28 AM
I was thinking the gaskets at the slip joints that some 4V bikes use.
Not at the head. Those gaskets should be replaced every time.
The only thing I've ever had good with down the road is WURTH copper anti-seize paste.
You don't want to hear about my agony having to cut a relatively new header of my Austin America after I'd used some Checker-Zone-Boys exhaust gasket sealant.
Quote from: dlearl476 on July 17, 2012, 03:35:51 PM
The only thing I've ever had good with down the road is WURTH copper anti-seize paste.
You don't want to hear about my agony having to cut a relatively new header of my Austin America after I'd used some Checker-Zone-Boys exhaust gasket sealant.
Better living through chemistry... ;D
Silicone.
If it doesn't work...
it digs out easy. [thumbsup]
Long time no post. Took a break from all forums for a while.
Came to post that I was having the same problem. Now I know where to start looking.....
2005 s2r800 with boomtubes. Ran fine when I winterized and this spring she pops like mad on decel.
Thanks guys.
My local guru seems to think that it is lean pop and suggests a power commander
He has no explanation for the pop that is coming from the intake
Quote from: lazyjinglin717 on July 22, 2012, 04:37:18 PM
My local guru seems to think that it is lean pop and suggests a power commander
He has no explanation for the pop that is coming from the intake
Pop from the intake is a symptom of lean.
Does sound like lean spittin' through the airbox. Is it worse when the engine is cold?
I don't notice much of a difference between hot or cold because it really doesn't happen often
Rode it today and it is running like crap. Sputtering and popping through the airbox at the lower RPMs when I accelerate. Seems to settle down when I get higher in the RPM range.