Farting giant

[poh]

Dear colleagues,

 

I have purchased a new Quat-D Ex-box for my V11 S (2001). The beautiful system makes a perfect fit on the bike. However, I experience some "exhaust banging" when I let the throttle off, and guess that it is due to air leaks close to the cylinder head? The bangs are not very sharp or loud (they do sound like giant farts!), nor do they appear very frequently, but are still a bit annoying/embarrassing. One could possibly argue that the system always sounds like a farting giant or a 1972 Fiat with a corroded muffler, but that is not the issue here. When I dismounted the Guzzi stock system I could not find gaskets between the cylinder heads and the head pipes. My question is: should the Ex-box head pipes/stubs (or other pipes for that matter) be mounted with gaskets or some kind of sealant, and if not, is the banging an inherent consequence of the design of the system? No cracks – I have checked. Please, spill over some of your unlimited experience.

[Guest Nogbad]

Sounds great to me! Where can I get one?

[pete roper]

There should be a gasket in the port, asbestos wrapped in(?) Aluminium? If they ain't there it'll pop and fart like a good'n.

 

Pete

[Mal]

As Pete says there should have been gaskets there originally, you definately need them with pretty much any exhaust.

 

Quite often the old gaskets are very difficult to see as they get crushed and covered in carbon etc and with their metal faces they just look like part of the cylinder head. A careful prying out with a small screwdriver or some such tool is required.

 

New ones are pretty cheap and easy to fit.

 

Other than that I hope you are enjoying your new exhaust.

 

Mal

[tomsp]

just wondering here because I have an exhaust pop now too -- do you hear the backfire/pop at the cylinder head or at the rear of the exhaust?

[DeBenGuzzi]

check the exhaust clamps I had a loose one that was causing me some pops. took 3 secs to fix.

[poh]

Thank you guys. I´ll look for the gasket and replace it. And for you DeBenGuzzi, there are no clamps on a Quat-D E-box, the kit is from the stubs and down held together with spirals - racing style! Tomsp, I think the farts are coming from the end of the system - it´s kind of tricky to tell since the end is situated down below (my own end).

I also sent the quiz to the maker who replied with that some sealant in the joints could make the trick. I would guess that he did´nt believe that I would try without a new gasket.

I´ll use my glasses the next time. Thank´s again.

[jimbemotumbo]

I can't be certain from your description, but it may also be "carb farts", which often happens when you suddenly lean out the mix (new exhaust!). Although FI is supposed to deal with this, I had it happen on my 00 V11 when I put on the stooky and M4s. The PCIII allowed me to isolate the lean spots and get rid of them. Until then, and at certain rpms/TP I would get short duration "farts". May be something to consider.

 

Jim