Exhaust bomb

Hey guys, when i bought my wr450f i got an aftermarket slip on with it and an uninstalled pipe... i wanted to test the full system today but when i took al look at it, i see an unusual piece of pipe sticking out. I don't know where its for or if it needs to be connected...

Take a look at the picture, you'll see what i talk about.




Interesting! I'm look at exhaust at the moment and have seen similar parts like that on a Yoshimura set up. Do you know if it's open all the way through that little pipe? I did read someone saying that a little pipe chamber that came off the yoshi set up helped to give it the torque. No idea personally though, following this for sure!

That is one freaky looking pipe set up.


Are you sure that is for the WR?  

It doesn't look, like it woud fit.

That extra pipe is probably there for something strange, like heater system.......

It's either a Bultaco or CZ pipe. Well maybe a Jawa.

It's either a Bultaco or CZ pipe. Well maybe a Jawa.


MZ.  Minerelli. Maybe Derbi or Fantic...

looks like DRZ400 with the single opening and large downturn.

I bet its not for your bike. Looks like it has a catalytic converter of some sort. I bet it for a bike that has a bunch of smog crap.

That tube is probably for an O2 sensor........

Or it's for a separate, tiny muffler.

Or it's for a separate, tiny muffler.



Or a Harvesting attachment.

Humph you guys.

The small pipe is a heat pipe like the air cooled VW's had.

When used on a motorcycle you simply put the pipe up your gass on cold days.

Thanks for the replies everyone, I do think it fits though, the header opening is the same size and the other side ends right at the beginning of the slip on.


the pipe is "open", i can blow in it and feel air comming out the other side...

it's also around the same size as the cooling tubes but i would be damned if i needed to cool my exhaust... and there is no other pipe where the cooling water would come out of...


the welds are crap so i thought maybe someone wanted to &%$#@! with me and welded the pipe on it but al the other welds aren't 10/10 either so i do think it's there for a reason!


why would the o2 sensor be that far away from the actual exhaust path ?


later on the day i'll just fit the thing on... i'll see what happens, if i get an extra 100 foot pounds of torque at 1000rmp i will let you guys know.

I put it on today ! I couldn't go for a ride because my plastic bash plate touched the bomb thingy and i didn't want it to melt... it fitted perfectly!

The sound was nice too, a lot deeper and louder ( duh, no muffler on the small pipe thingy ).

I still have no clue in the world what the pipe is for though

Then the small pipe thingy was pointing at your carb blowing header temp exhaust at it?



I'll bet that wouldn't cause any problems.  Sort of a fuel per-heater!!  :ride::mad:



What year is your WR?  And, send some pix, because that big "bomb" thingy looks like it would bump the front fender too...

It pointed at the radiator actually, the carb was a little further to the back.

It's a 2009 wr.

I forgot to take any pictures but i will next time. It fitted quite well actually, it didn't got in the way, i think its even small enough for off road riding without damaging it at all.

It doesn't stick out to the front though, it hangs down the side.

Ill keep you updated

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