Over Run on a 1150gs adv

[Anthonypowell]

Is it normal for poping through the Exhaust on the overun when I lift of the throttle. The Cat has been removed and the fueling has been set up as per Steptoe instruction. Sometimes it sounds like a backfire,

Thanks tony

 

[fatnfast]

You don't say what 'can' you are running, but with a remus/free flowing can popping on the overun is pretty normal. Mine even emits some nice flames every now and again. You might want to check that the pipe is sealed properly at the joint to the Y-piece, which can help.

 

[ockier]

I ve the same "problem" on the same....1150gsa. I took the cat out and replaced with remus y pice with original pipe. sounds like back fire. I was told to switch from 98 to 95 octane. this did fix it.

 

[guzzimag]

They all do that sir - even worse with standard can it's like a bloody shotgun. Nowt to worry about

 

[John Armstrong]

They all do that sir - even worse with standard can it's like a bloody shotgun. Nowt to worry about

Unless you have the plastic panniers

 

[longdog]

They all do that sir - even worse with standard can it's like a bloody shotgun. Nowt to worry about

Bl**dy right there!! I've got a Remus Y piece and standard can on and the Steptoe link and when it backfires!!!! Jeez! It makes me jump! Trouble is, it's not consistent either. It may not backfire for days, then some days it's every time I shut the throttle!!!

 

[david306]

I am running a Y piece and a Carbon Can Co end piece and i have perfected the backfire with 6" blue and orange flame... The engine has to be warm for starters, then simply using third gear, speed up a little to about 4000 revs then back off but not fully off throttle, you should hear a rumble from the back which will build up in depth and then back it fully off and....bang !!!!... you get a nice flame and a loud pop which can scare the crap outta people sitting beside you with a car window open or something...


Not that i would do that...


Its even louder when i take out the baffle as its straight through...

 

[guzzimag]

Bl**dy right there!! I've got a Remus Y piece and standard can on and the Steptoe link and when it backfires!!!! Jeez! It makes me jump! Trouble is, it's not consistent either. It may not backfire for days, then some days it's every time I shut the throttle!!!

I had a cyclist shouting "you f***ing tw*t!" at me once when the old girl backfired as I was coming up to a junction - poor bugger nearly feel off his bike Not so bad with the remus more of a popping than a full on explosion

 

[Womble]

I am running a Y piece and a Carbon Can Co end piece and i have perfected the backfire with 6" blue and orange flame... The engine has to be warm for starters, then simply using third gear, speed up a little to about 4000 revs then back off but not fully off throttle, you should hear a rumble from the back which will build up in depth and then back it fully off and....bang !!!!... you get a nice flame and a loud pop which can scare the crap outta people sitting beside you with a car window open or something...


Not that i would do that...


Its even louder when i take out the baffle as its straight through...

LOL - a few years ago I'd have been very worried to try stunts like that around Belfast.

 

[Womble]

Going back to the original question about popping, it could be that there is still a problem. They may 'all do that' but it might be possible to make it better.

I have backfires on the overruns (decatted 1150GS) and it got worse when I went back to my original pipe from my Scorpion. I took it apart at the weekend when I was swapping the wheels, and reassembled it with gun gum to make sure that there were no air leaks.



If anything, it's worse

Although, I did fit a K&N filter at the same time, so it could be that as well

I've got the 24k service coming up, and once I've sorted that, it's off to the Dyno to get the Techlusion properly adjusted.

 

[GS TRV]

Mine does it too - I've a Remus and Y piece.

problem? I think it's cool

 

[pomm001]

Mine does it too - I've a Remus and Y piece.

problem? I think it's cool

Mine with a Y and STD can does it, but it’s something that bothers me so one of these days I will try a few mods to see if I can make it go away
The main issue is on the overrun throttle butterflies closed the ECU shuts of the fuel supply signal to the injectors as the revs drops the ECU switches the signal back on again to fuel the engine.
This weak fuel air mixture ends up going down the exhaust pipes and collects; it needs oxygen to burn so dependant on the system dynamic and where it can draw the air in to burn the fuel either explodes in the Y piece or can.
With the CAT in the system this would be damped out or even burnt in the CAT as it would still be up to operating temp.

What I want to try when I can get around to it is take the bungs off the throttle bodies connect together and run through a solenoid valve (normally closed)
When on the overrun ( throttle closed ) the TPS signal voltage would open the solenoid valve to atmosphere thus letting some clean air to the other side of the butterflies which should purge the and cool the explosive charge out of the system
The valve would remain open until the injector signal switches the injectors on again.
Downside to this is there would be some lost engine braking
Most of us know how to avoid the ‘popping’ by keeping the throttle slightly ‘cracked open’ on the overrun and opening the throttle slightly earlier
This is what my mod would hope to achieve, its just trying to find the time / and or motivation to try it