Reducing Decel Popping?

[barbagris]

I would say - It wont hurt to try. I'm not sure but iirc the first Hanso Tunes were done very much with input from Wayne Tripp.

I will take a harder look at it all today - once I plug in a bigger screen. I find it hard to visualise without having TuneECU, Commander and Winpep open and visible together. I'll print off one or two graphs and put them in the MAP tuning thread.

 

[barbagris]

How do you do that ?

Set Speed limiter on. Put secondaries at 10% above 3000rpm , disconnect one plug in each pot.

 

[Claviger]

You and @phil ewins have the same issue and both use the outlaw system. Doesn't that system use a piece of flex pipe to attach the muffler to the header?

If so, I'm going to point a big fat finger at the flex pipe as your point of ignition in the exhaust causing the popping. They're small, elevated into the gas flow and steel so will retain heat for ages.

I still think you both have a leak on the vacuum or exhaust side.

 

[phil ewins]

You and @phil ewins have the same issue and both use the outlaw system. Doesn't that system use a piece of flex pipe to attach the muffler to the header?

If so, I'm going to point a big fat finger at the flex pipe as your point of ignition in the exhaust causing the popping. They're small, elevated into the gas flow and steel so will retain heat for ages.

I still think you both have a leak on the vacuum or exhaust side.

No flex pipe attached to headers

 

[Tal]

This may very well be the dumbest thing suggested on this forums entire history but....the most common reason for decel pop is manifold bolts not tight enuff!!!...dosn't take much either...
ok, ok,....i'll have another rum and keep reading....

 

[barbagris]

You and @phil ewins have the same issue and both use the outlaw system. Doesn't that system use a piece of flex pipe to attach the muffler to the header?

Rob - The pictures posted show fixed pipes as do DavePlatt's ad's. BUT the expansion chamber available is MINISCULE. So no controlled exit expansion - Think MUZZLE BLAST - Megaphone exhausts exist for a reason - as you know.

@Nat67 has Outlaws and when he came past me it sound like a belt fed shotgun. Uncle Natty-poo has not mentioned if he has popping.
If he does NOT then as you say - a leak seems possible - I am very OCD about routing stuff and repositioning the MAP sensor so there were no kinks in the tubes was time consuming.
An exhast leak somewhere would also do some pulsejetting. If he has popping - and knowing how fussy Nat is about motors - then it is an inherent issue with Outlaws.

They are that open (visually) - would also NOT surprise me if between exhaust pulses they draw in some clean air - like a pulsejet assisting unburned gas combustion therein. Bit like a V1 rocket engine (Schh tell no body how I know).

Would actually be interesting (once I have the Travelguy-Jardines & THUGS dialled in) to see how different a set of Outlaws is. I do not like the Gas splitter union at all on DP's pipes. I know it is partially a problem with the ABS boxes.

 

[Nat67]

Rob - The pictures posted show fixed pipes as do DavePlatt's ad's. BUT the expansion chamber available is MINISCULE. So no controlled exit expansion - Think MUZZLE BLAST - Megaphone exhausts exist for a reason - as you know.

@Nat67 has Outlaws and when he came past me it sound like a belt fed shotgun. Uncle Natty-poo has not mentioned if he has popping.
If he does NOT then as you say - a leak seems possible - I am very OCD about routing stuff and repositioning the MAP sensor so there were no kinks in the tubes was time consuming.
An exhast leak somewhere would also do some pulsejetting. If he has popping - and knowing how fussy Nat is about motors - then it is an inherent issue with Outlaws.

They are that open (visually) - would also NOT surprise me if between exhaust pulses they draw in some clean air - like a pulsejet assisting unburned gas combustion therein. Bit like a V1 rocket engine (Schh tell no body how I know).

Would actually be interesting (once I have the Travelguy-Jardines & THUGS dialled in) to see how different a set of Outlaws is. I do not like the Gas splitter union at all on DP's pipes. I know it is partially a problem with the ABS boxes.

Ah yes , the term you are looking for Mr B , is reversion . Where fresh air is sucked back up the open exhaust , thus supplying o2 to the unburnt fuel for easy ignition by the hot pipes ! My bike will pop and bang , but as I mentioned before , depends largely how I ride it . If I ride hard she don't really pop , just Burble but if I plod in high gears , she will bang most loudly on overun. This is great , as I can be selective as to whom I piss off !

 

[barbagris]

Ah yes , the term you are looking for Mr B , is reversion .

At my age - I start to forget the odd ........ erm you know. Those thunammies that tell you what a doobry is. Words - that's what they are - Yes! - words.

Reversion! - that's the kiddy. And from the shape of the Outlaws - this effect would not surprise me one iota. Selective annoyance functionality. We could market that.

 

[Nat67]

At my age - I start to forget the odd ........ erm you know. Those thunammies that tell you what a doobry is. Words - that's what they are - Yes! - words.

Reversion! - that's the kiddy. And from the shape of the Outlaws - this effect would not surprise me one iota. Selective annoyance functionality. We could market that.

I try to be annoying most days , but some days more annoying than others !

 

[TURBO200R4]

i kept telling myself do not read this thread do not read this thread do not read this thread
yesterday i read the thread
this is just my opinion
when i was young i would pull the distributor out of my old chev put it in a vice install new points and set them with a paper match book cover reinstall and set timing by ear sometimes had to back off because the starter was working hard when it got hot.
i have never seen or heard of anyone tune a motor by listening to exhaust backfires in my life.
it seems to me the prob is u put a racing exhaust system on your bike and now it makes noise
in the old days we would throw a big carb on to get it to run good and we would have gas going by the piston rings into the oil messing up the works. now the injection system with o2 sensors really makes for a nice system engine runs good and no more gas in the oil.
i guess my point is with the muffler it will suck air into the pipes and bang the best way to cure the bang would be to put a better system on(smaller exhaust port) or build a flapper plate with a smaller hole to restrict the air from being sucked in.
i run 3 tors and when they get hot they bang. sometimes i let them bang and when i dont want them to bang i pull the clutch in. a compromise i can live with