TO RESTRICT OR NOT TO RESTRICT

[technicolorhighway]

I am planning to tune the carbies and not sure which is the best approach.
i have a set of REMUS exhaust on.

do i

tune with the baffels/dbkiller on?
i have my track day,will it be ok and ready to go when i take the baffles/dbkiller off?


or i

tune it without the restrictor and put in the baffles/dbkillers for my daily rides.


thanks

[gilson]

Hi there,
a suprising bit of info I was told recently was that baffles are dangerous and can damage the head gasket. I didn't ask how as it came from a good source but I presume something to do with the back pressure?

So I'd recommend no baffle and if your pipes are loud, repack them.

Also you only need to worry about noise if you are going to a quiet day, 99db day and even that is still quiet loud. 105db are very loud and almost sounds like something is wrong, I. E. A repack is required.

Just my thoughts....

[sirch345]

Hi there,
a suprising bit of info I was told recently was that baffles are dangerous and can damage the head gasket. I didn't ask how as it came from a good source but I presume something to do with the back pressure?

That surprised me too, surely if a head gasket can withstand the pressure of an explosion in the cylinder head, the back pressure from an exhaust would be bugger all in comparison ?

I'm also surprised too hear that too
I'm inclined to think along the same lines as Mike. Also the standard cans (silencers) with be giving more back pressure than Decibel killers will.

Getting back to the original question. If you intend to use the bike on the road without the baffles fitted, then as that's where you'll be using the bike the most, I'd tune it without the D/killers as Gilly said. But before you tune it just be sure you're going to be happy with it being that loud first, IE. not going to be pulled all the time, or annoying the neighbours.

Chris.

[Zakalwe]

Sounds like chewed grass* to me, dreamt up by someone who knows bugger all. The pressure in a combustion chamber is far far higher than anything experienced in an exhaust pipe.










*bullshit

[Beamish]

Baffles in or out should not affect the head to that extent. Granted it may run rough but as a rule of thumb bikes are set up from the manufacturers to run lean hence lowering emmisions and noise . Lean engines run hotter and can benefit from a richer fuel/air ratio set up. Apparently most of the SP fuelling issues are caused by Hondas low RPM fuel/air ratio settings

[Zakalwe]

Baffles in or out should not affect the head to that extent. Granted it may run rough but as a rule of thumb bikes are set up from the manufacturers to run lean hence lowering emmisions and noise . Lean engines run hotter and can benefit from a richer fuel/air ratio set up. Apparently most of the SP fuelling issues are caused by Hondas low RPM fuel/air ratio settings

I'm open to correction, but most standard bikes run rich, not lean. WRT the SPs they run notoriously rich. I have heard that Honda got their knickers in a knot when there was reports of US based RC-51s running waaaay too hot (the side mount radiators are a bit marginal at best, especially in traffic). They made the fuelling richer to help lower the temps (as you have said, a rich mixture will make for a cooler combustion burn) on the SP2s and fitted a second radiator fan..

With increasing emissions restrictions, bikes certainly do run leaner than of old (hence the use of lambda (oxygen) sensors in the exhausts). Lambda sensors only work up to about 40% throttle openings, and cannot sense rapid changes in oxygen content. They are only useful when pootling about or at low rev ranges (perfect for emissions testing though). The standard bikes still run richer than optimum though.

[Pete.L]

Spot On Z
and if you tune your bike with out baffles when you put the baffles in it will run rich too and not cause any damage.
If you tune the bike with the baffles in and then run it with them out it will run lean and you risk burning your exhaust valves out.
Of course if you weren't so cheep you could tune it for both and change your tune when ever you wanted to change your baffles.It's a bit more of a pain on the Firestorm but on the SP all you have to do is upload another map

Pete.l

[gilson]

Sounds like chewed grass* to me, dreamt up by someone who knows bugger all. The pressure in a combustion chamber is far far higher than anything experienced in an exhaust pipe.

*bullshit

It surprised me too but it's what Roger Ditchfield told me when he gave me back my Firestorm after tuning the Moriwaki Stage 1 engine....he returned the baffles in a box and said never to put them in as they can damage the head gasket. Maybe I mis-heard what it could damage...Maybe this just applies to this engine tune??

[Beamish]

Spot On Z
and if you tune your bike with out baffles when you put the baffles in it will run rich too and not cause any damage.
If you tune the bike with the baffles in and then run it with them out it will run lean and you risk burning your exhaust valves out.
Of course if you weren't so cheep you could tune it for both and change your tune when ever you wanted to change your baffles.It's a bit more of a pain on the Firestorm but on the SP all you have to do is upload another map

Pete.l

That was my plan with the SP to have two maps on the PC3 set up on the dyno, one with baffles and one without. It was the guy at the Dynomax that said the SP2 runs lean at low revs hence the snatchy response, he said the first thing he does is richen the mixture at the bottom end (may have misheard and happy to stand corrected if I am wrong .)

[gilson]

Sounds like chewed grass* to me, dreamt up by someone who knows bugger all. The pressure in a combustion chamber is far far higher than anything experienced in an exhaust pipe.

*bullshit

It surprised me too but it's what Roger Ditchfield told me when he gave me back my Firestorm after tuning the Moriwaki Stage 1 engine....he returned the baffles in a box and said never to put them in as they can damage the head gasket. Maybe I mis-heard what it could damage...Maybe this just applies to this engine tune??

From the Great RD:

2. I remember you saying something about not using baffles (when you returned them in a box after you tuned my Firestorm engine) as they can damage the engine. Was it the head gasket that can suffer? and why would this happen?

"Yes, the head gasket can blow and the exhaust valve seats burn prematurely because the "V" twin relies heavily on the exhaust pulsing to scoure the cylinders and baffles fitted into a freeflow exhaust that was not designed for the engine can cause these problems.as well as general overheating problems above the ones that SPs have anyway."

All very interesting....

[sirch345]

Good man Gilly for getting a reply from Roger on that

I remember you saying something about your Moriwaki tuned Storm's engine having leaking valves, that Roger found and put right. I presume the bike must have been running with the baffles fitted by the previous owner

Chris.

[tony.mon]

So having baffles can lead to burning valves, and that means lower compression, less engine efficiency and inevitably you'll (not knowing about the state of the valve seal until you strip the top ends) just use more throttle to compensate for less power.

Obviously this would use more petrol.


SO, officer, my straight-through exhausts are saving the planet.
Any more smart comments?


(or shall we just get on with the speeding ticket......)

[Pete.L]

Spot On Z
and if you tune your bike with out baffles when you put the baffles in it will run rich too and not cause any damage.
If you tune the bike with the baffles in and then run it with them out it will run lean and you risk burning your exhaust valves out.
Of course if you weren't so cheep you could tune it for both and change your tune when ever you wanted to change your baffles.It's a bit more of a pain on the Firestorm but on the SP all you have to do is upload another map

Pete.l

That was my plan with the SP to have two maps on the PC3 set up on the dyno, one with baffles and one without. It was the guy at the Dynomax that said the SP2 runs lean at low revs hence the snatchy response, he said the first thing he does is richen the mixture at the bottom end (may have misheard and happy to stand corrected if I am wrong .)

2 maps...Sounds like the best plan
The SP does run a little lean low down and then richens up through the mid range. The Firestorm is predominantly rich through the whole range.
Only problem is, that's a generalization. As soon as you change an exhaust or a filter it's going to be different for your bike.
Roger is quite right about the baffle putting extra pressure on the head but you have to keep that statement in the right context. If you are racing and looking for optimum performance, you don't want the baffle. You are probably pushing everything to its limits and you don't want any extra strain on anything. If you are well with the tolerances of the engine, you can put a baffle in line and fuel it to suit. All of our road going bikes are designed with fuel and noise restrictions built in. The engine and frame will also have an expected life time too. (80k miles for the SP before a major engine rebuild is recommended...under average use) Race the bugger on track and you are supposed to do a rebuild at least every season.
Oh! and don't stick potatoes down your exhaust, it's not big and it's not clever

Pete.l

[tony.mon]

Oh! and don't stick potatoes down your exhaust, it's not big and it's not clever

Pete.l

I'd heard that chips gave you more power.....

[Pete.L]

Oh! and don't stick potatoes down your exhaust, it's not big and it's not clever

Pete.l

I'd heard that chips gave you more power.....