Ducati Monster Forum

My HM1100Evo comes with a DP 2 into 1 full system. Even at speed my pillion in a million gets gassed by the exhaust. It's fine solo, but I think there is an issue which a wind tunnel would show up.
The exhaust exits well behind the pillion, but I think the issue is similar to when we used to drive station wagons with the rear window wound down back in the day ;).
There is no such issue with my old M900, even though the pipes exit alongside the pillion (but down low).

I'm considering going to a stock system with the two mufflers, but this is no guarantee of success.
I have removed the DP wind screen in an attempt to change the airflow. I'll test that in a couple of days.

Meantime, anyone have any experience of this, or any solutions?
Cheers.

First silly suggestion would be to ride faster.  ;D

I've not heard of the issue, but that's not worth much in this case.

I've had weird aero interaction between my pillion and my helmet, subjecting me to a bobble-head effect, very annoying.

Is this the system you've got?

(http://i1064.photobucket.com/albums/u364/Auto_Enthusiast/5N35E45Me3E13Kb3Nac97db43a0439cdc1e3e_zps134de5d2.jpg)

Are you running the dB killer/insert?

That's the one. No DB insert. The bike came with it. If removing the screen doesn't help then I'm considering buying a stock system. It's the pillion bike.
Cheers.

Perhaps an 'elbow' that goes in place of the insert to direct the exhaust more horizontal and outboard may do the trick?

I'd say cobble something crude to bolt in there as an experiment, see if you can solve it that way.
May have to try a few different concepts.

Do you have a few 'test-pilot' pillions to do the donkey work with, then present the solution to the Pillion In A Milion?

Lab rat kids ;).

Maybe a modified DB killer ay?

Something like that, yes.

Just crude and simple stuff to try to get clues on which way to go.
Try to direct the exhaust down a bit and outboard to get it away from the zone directly behind the pillion.

Is the gassing occurring around town, low speed, or at cruising speed on the highway?

At all speeds up to 70 mph, much to my surprise. :P  Hwy was quite bad.
Tested on closed course conditions of course.

Nothing to add to Speeddog's suggestions.  Without a wind tunnel it is all guesswork.  My concern with returning to the stock exhaust is, with the cats, your Pillion might still be gassed, but without the stink as a warning. 

Cats, like squirrels, can be dealt with ;D
Aint the cat cleaner?

Cat is 'cleaner', but doesn't eliminate the CO.

  Its the CO Im worried about.  :P

buy a cheap smoke grenade (they used to sell 50 cent ones that last for 30seconds in the grocery store, or you can always make your own (they arent hard to make a home made one either)

they got hot, but thas easily solved. take one, light it up on a street and go for a ride!!! ;D.

Science though, behind the passenger is low pressure, the exhaust is probably getting sucked into their burble.

nothing you can do about it unless you actually ride SLOWER to reduce the pressure gradient, or you redirect the exhaust. maybe you can change the cap without having to go with an insert.

Thanks fellas.
A twin system straight out the back would have to protude a fair way ay?
Or the current pipe less tucked in and angled straighter?

Lab rat 1 said that the fumes were worse sitting back than when holding on close. Also that the fumes became strong when I lifted my elbows [laugh] (might need more deodorant). Smell went away with elbows tucked in. (How would Spies go)? Head over my shoulder no fumes noticed.

I'll get the GLW (pillion in a million) to try it with no screen and the pipe moved. Then if that works I'll try again with the screen fitted. A local exhaust guy could give a slight bend if needed.

I found the pipe can move down and out and inch or so. I'll make a bracket and try that. This test was with no screen, and to be honest I didn't notice much difference than with it on. Maybe less buffetting :P.

I may still get an oem system for other reasons.

Thanks to all you guys for giving me some direction with this. Love this place.
Cheers.

Sounds like you're rooted Tony   [laugh]




 ;D

There is a 2 into 1 into 2 DP full race system in the catalogue 8).
Just sayin'.

Moved the pipe as much as it will let me. It helped somewhat but is still too close to the pillion. The pipe will need some bending.

I don't know if the oem dual muffler location will be any better. The option of a performance 2-1-2 system probably gives the best performance, but is an expensive failure if the pillion still gets gassed. It may depend on how far back they protrude.

I will try some pipe bending (neighbour has an exhaust shop) to get the 2-1 muffler down to a level that works, but still exposes the back wheel.

Some interesting observations.
My GLW was able to communicate with me in real time via a Scala rider to pillion system.
1. If I turned my head to the side the exhaust fumes increased for her.
2. If she sat back with a gap between us she smelt more exhaust.
3. When tucked up close looking over my shoulder she smelt no exhaust. 4. With the flyscreen fitted when I raised my elbows the fumes were less, the opposite of the no screen test with my daughter.
5. With the pipe lowered, there were less occasions when she smelt the fumes at all speeds.

The pipe lowered a couple of inches or so reduced the fumes noticeably so I'm hopeful lowering it more will work. The GLW has never smelt fumes while being pillion on my 900 Monster. I don't intend to bend the pipes that low, but somewhere around upper tyre height will hopefully do the trick.

When bending lower are you also bending the can to a more horizontal position?  This might help since you are changing the angle of the exhaust plus moving the tip rearward.  Or not.  Dunno.

Yeah, I'm definitely trying to go more horizontal. It points up in the stock pos-n at quite an angle. I'll get it to a pipe bender next week.

^^ Sounds like a win+win solution  ;D  ;) ;)

 ;) ;D
Wink wink nudge nudge say no more!

cut the pipe at the center point of the wheel & remount the can about 1' lower, same angle,  much like the position of M900 low pipes. would need custom strap/ bracket mount.

https://www.youtube.com/watch?v=SrDFGa0juCM (https://www.youtube.com/watch?v=SrDFGa0juCM)


your wife.....is she a....go-er? no what I mean?

Candid photo's? [laugh]
One of my favourites. There is a park bench version which is even better.

I'm aiming for about top of rear tyre height with only a slight upward angle nearly horizontal. It also will push the outlet further back towards the rear of the bike. That should do it.

An update.
The pipe will not be bent, instead a small extension of the correct bend will space it down and extend it back an inch or two, nearly horizontal at about upper tyre height. The pipe can go back to stock easily for sale if this doesn't work in case I am forced to buy a Spark  performance 2 into 1 into 2 system. According to the DP catalogue, the 2 into 1 into 2 system makes the most power.

I saw a Kanma blurb that seemed to say that a shorter 2 into 1 system made the most power on their tests. It has a muffler coming out in front of the tyre quite low.

These guys at the exhaust shop could fab that short 2 into 1 kind of thing quite easily using my existing muffler and headers. It would fit between the tyre and passenger footpeg like the 1200MTS kit. I bet these guys could make it cheaper than me buying the complete Spark system. All I would need is the 2 into 1 junction and a small bracket.

Well see if this mod passes the GLW sniff test.

Well, the pipe worked in two out of three siuations. Riding straight was ok, banking right was ok, banking left was not. Of course the pipe is on the right. Left hand sweepers raised the pipe outlet to the centre line.

I had the pipe lowered further with a cut n shut removing a few inches that has put it close to the MTS1200 Termi postion. It sits at upper tyre height.

The angle upward is less but still rakish and the pipe sits much lower and forward which seems to help.  It actually looks better imo. Interestingly the bike runs better with the final 54mm section to the muffler being shorter.

Pictures Tony, pictures  ;D

 [popcorn]

I could always "out" you  [laugh]

(http://i1024.photobucket.com/albums/y304/tonykokonis/1024x768_bestfit%2016_zpsxc260gxg.jpg)
Long overdue. Sorted laptop and photobucket. Dropbox did not like me as I wasn't a hipster.
The shortened exhaust on my Hyper. Closer to the newer exhaust positions of the new Hyper and Multis. Looks pretty good too. No more gassing the GLW.

(http://i1024.photobucket.com/albums/y304/tonykokonis/20150617_105051_zpsyypz8qmz.jpg)