weehe
Junior Member
Sounds good, I will turn it down to 1100rpm to start. I do mostly highway for commuting so hopefully will work.
Single Massive Backfire
Sounds good, I will turn it down to 1100rpm to start. I do mostly highway for commuting so hopefully will work.
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You get my PM??
weehe
Junior Member
I did sorry, have been on my phone and have problems replying to them. I am good :thumbup:
weehe
Junior Member
Well I let the bike warm up, rpms started around 1800 then dropped to 1350ish once I got a bar on the coolant temp. I adjusted the rpms down to ~1100 and went for a ride. The backfire is still there. It seems I can very easily repeat it too. It is only after 3-4+ seconds of 4000+rpm decel. Once I stopped riding my idle staid at 1200 rpms, not 1100 anymore. Doesn't look like the previous owner added the ground wire to check CO. I will have to do it tomorrow. I took a 2 min warm up video to show idle, but everything seemed normal. Let me know if you still want me to post it.
Next steps will be install ground wire and check CO values, buy a manometer and do TB sync, look into valve check/adjustment.
Next steps will be install ground wire and check CO values, buy a manometer and do TB sync, look into valve check/adjustment.
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1,800 cold is SUPER HIGH, even cold. Something is definitely NOT right...
My cold start (80's ((F)) outside) is about 1300, warm it drops down.
I agree a manometer and TB adjust wouldn't hurt and may show a specific cylinder jumping about, etc.
Just for a reference, here's a video of my bike (checking voltages), from a COLD start to warming up. You can see the RPM's and possible hear the difference from cold enrichment to operating condition, as it warms;
https://www.flickr.com/photos/127092600@N08/
My cold start (80's ((F)) outside) is about 1300, warm it drops down.
I agree a manometer and TB adjust wouldn't hurt and may show a specific cylinder jumping about, etc.
Just for a reference, here's a video of my bike (checking voltages), from a COLD start to warming up. You can see the RPM's and possible hear the difference from cold enrichment to operating condition, as it warms;
https://www.flickr.com/photos/127092600@N08/
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weehe
Junior Member
I'm going to bite the bullet and buy the Morgan Carbtune, i'd rather have a high quality piece. Do I need any adapters or tools/accessories they offer before I order?
What year is your bike and is the exhaust stock?
Lastly, did you check the CO values?
To some extent, a rumble while coming down from RPM is not uncommon or a indication something is out of place...
I cant compare mine to well as it has some changes. Specifically those which help the rewet on corner exit can induce a fair amount of reburn in the exhaust. i.e. adding fuel via fuel controller. Especially if the throttle is cracked partially going down a hill.
I should have a audio somewhere... I'm just saying, even with a perfect TB sync, it may still pop on decel.
One quick test for the AIS leaking would be to have the air box lid off, have it running, and try to blow air into the AIS inlet in the airbox. It should not flow air while parked at idle.
I'd like to hear a video of how bad this issue is... Can you make one?
Audio track of some decel popping while descending a hill. Likely in 3rd gear with the throttle just cracked to maintain speed.
Click link -->> Soundcloud.com MP3 Audio - FZ6 Decel pop through 2 Bro cans
Listen from 1:20 to 2:50 or so.... You'll hear it crackle and pop descending a hill at about 45 mph
Is yours this bad? Is this what you want to fix? Pop/Crackle?
2008 Bike has:
AIS block off plates
S1 header w/Cat delete midpipe
Open 2 Bro Exhaust (P1X tips out)
Ignition advanced to 11.5° (stock is 5.0°)
Bazzaz Fuel Controller, mapped to reduce rewet (13.0:1 AFR)
Click link -->> Soundcloud.com MP3 Audio - FZ6 Decel pop through 2 Bro cans
Listen from 1:20 to 2:50 or so.... You'll hear it crackle and pop descending a hill at about 45 mph
Is yours this bad? Is this what you want to fix? Pop/Crackle?
2008 Bike has:
AIS block off plates
S1 header w/Cat delete midpipe
Open 2 Bro Exhaust (P1X tips out)
Ignition advanced to 11.5° (stock is 5.0°)
Bazzaz Fuel Controller, mapped to reduce rewet (13.0:1 AFR)
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I've owned the Morgan Carb tune for about 4 years and you don't need anything additional. Its paid for itself MANY TIMES over and is extremely accurate and easy to use.
Short of open Scorps and Iridiums, the engine is bone stock (CO#'s never changed) and I get NO backfire/popping, etc, even from a hard run to 13,500 and full throttle shut off back to idle..
weehe
Junior Member
I have an 04 with stock exhaust. I have not had time to check CO values, will probably have to wait till the weekend. I realize some crackling is normal, but this is a pop that is louder than a gun. On occasion there will be quiet pops after the loud one that I would consider normal. I will try and get a video for you, hopefully my phone has good enough sound quality. I'll try and do the air test, but will also probably get pushed to the weekend.
On a side note. If i decel and am just slightly on the throttle, i get no backfire/popping.
weehe
Junior Member
Sounds good, putting the order in today.
Typically most are trying to solve the little repeated crackles (like audio I shared). And more often those are a product of Air or Fuel or both in excess when its believed the throttle plates are closed. Remember the engine is a big pump always sucking in air and pushing it out. Along the way it usually burns the fuel going through but during times of high rate of deceleration the vacuum is so high the ratios get off and causes reburn in the exhaust. YOURS waiting to reach CRITICAL MASS is a little different variant. Perhaps you need to imbalance it a little as an experiment to see if it will do many small burns vs one BIG ONE!?
Typical issues:
AIS - valve leak adding air
Exhaust system leak - adding air
Intake leak - adding air but likely wouldn't idle down to 1200 if this is true
CO offset - adding fuel
Fuel Controller - adding fuel
TPS - out of adjustment - adding fuel. Verify Settings
Over advances ignition timing
Exhaust valves not closing completely and/or synchronized (adjust valves)
In my case, the ignition being advanced coupled with fuel being added from 2K to 7K leads to decel popping. Mind you its getting 45 - 50 mpg on this map and you can hear it goes through the gear pretty quickly.
Should you get bored some time, set the idle speed to 1350 and and repeat decel tests just to see what it does...
In the audio I shared that's descending a mile long hill where its just on the bubble. i.e. closing throttle completely and I'd slow too much so its just barely cracked. Essentially coasting but neither accelerating or decelerating. Hence fuel is being added from Fuel Controller offsets for 0 & 5% TPS angles....
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This is Very interesting, ^^^.
Pretty much eliminates a burned exhaust valve or valve too tight and points towards a mix issue..
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weehe
Junior Member
I am leaning towards a combo of things that may be causing this. First my CO values were set higher, injecting more fuel. Second, my TB are out of sync causing too much air to get in while decel. With too much fuel some could get into the exhaust and get held up on the cat. Then when I decel and no fuel is being injected the extra air causes a leaner than normal condition which burns up all the fuel on the cat with one big pop.
I could be way off, and I will check the CO values this weekend or sooner and will know. Will probably take time for the manometer to get here. Hopefully checking both these will reveal the problem. I'm hoping there is no unknown fuel map or valve problems.
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I seriously doubt its an OEM ECU map issue. When they break, they flat don't work (from what I've read here).
I'd have to read up on checking / cleaning the AIR PUMP/system to make sure that's working properly and rule that out.
The TB sync should help give some answers and at least rule that out.
I'd have to read up on checking / cleaning the AIR PUMP/system to make sure that's working properly and rule that out.
The TB sync should help give some answers and at least rule that out.
weehe
Junior Member
I was more meaning if the previous owner put a PC map on and didn't take it off. But it is suspicious to me that the previous owner replaced the fuel pump right before I bought it. I haven't read about those going bad. But like you said the CO values and TB sync should tell a lot.
Do keep in mind that the CO values directly impact the TB Sync vacuum. So if you change the relationship of C1/C2 it will alter vacuum readings at sync time. That is; if you mess with C0 values, plan to re-sync unless you maintain the SAME relationship and MOVE both C1/C2 equally +/- the same amount (you should be able to get away with that).
Idling condition OEM Specs:
Engine idling speed: 1250–1350 r/min
Intake vacuum: 29.0 kPa (8.6 inHg) (218 mmHg)
Water temperature: 95.0–105.0 °C (203.00–221.00 °F)
As for the actual TB sync:
If you can't hit 210 - 220mmHg, don't hesitate to move the #1 screw. That said, the CT devices resolution is not accurate enough to use as a stand alone measuring tool (major graduations are 20mmHg) to hit the OEM spec as its best guess of +/-1.0cmHg (+/-10mmHg).
When you're done with TB, make sure you still have range control of idle screw. i.e. it adjusts from 1000 to 1500 RPM.
Last little bit: If while holding it at say 5K and one needle sores above the rest it's a good indication the valves need adjusted.
Idling condition OEM Specs:
Engine idling speed: 1250–1350 r/min
Intake vacuum: 29.0 kPa (8.6 inHg) (218 mmHg)
Water temperature: 95.0–105.0 °C (203.00–221.00 °F)
As for the actual TB sync:
If you can't hit 210 - 220mmHg, don't hesitate to move the #1 screw. That said, the CT devices resolution is not accurate enough to use as a stand alone measuring tool (major graduations are 20mmHg) to hit the OEM spec as its best guess of +/-1.0cmHg (+/-10mmHg).
When you're done with TB, make sure you still have range control of idle screw. i.e. it adjusts from 1000 to 1500 RPM.
Last little bit: If while holding it at say 5K and one needle sores above the rest it's a good indication the valves need adjusted.
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If you have an aftermarket fuel addition, it'll be very noticeable under the seat.
Please check and see ya or nay if you have one, that can make a difference....BIG TIME...
Unless you send the stock ECU out for a PROFESSIONAL re-map (about $500), it cannot be changed.
Re the fuel pump, yes they do fail. Especially if the bike is parked over say winter with a half full tank. The upper, inside of the tank rusts, the rust gets sucked into the fuel pump filter, (not really serviceable) and the pump is ruined. The pump is cooled by the fuel, so running it low to dry isn't the best thing for it...
Here's a pump filter with rust/crap in it;
Please check and see ya or nay if you have one, that can make a difference....BIG TIME...
Unless you send the stock ECU out for a PROFESSIONAL re-map (about $500), it cannot be changed.
Re the fuel pump, yes they do fail. Especially if the bike is parked over say winter with a half full tank. The upper, inside of the tank rusts, the rust gets sucked into the fuel pump filter, (not really serviceable) and the pump is ruined. The pump is cooled by the fuel, so running it low to dry isn't the best thing for it...
Here's a pump filter with rust/crap in it;
If it died from RUST - could be **potentially** point towards leaking injector..... A sync screw being off say (guess) +/-1/2 compared to the others might point at this...
Also, count the turns out from bottomed of all sync screws and record them before MOVING THEM!
