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Discussion Starter #1
Just picked up a tidy 749s for the wife .
Cleaning her up I noticed the rear vertical mid pipe is loose between the header and exhaust.
Also the rear is mild steel and has surface rust the front mid looks to be SS no rust.
Then noticed there is a huge difference between the front horizontal mid pipe and the diameter of the rear vertical mid pipe diameter aprox 10 mm . 55 front around 45 rear .
Also not sure what exhaust comes standard on this bike it doesn't look and sound stock but isnn't marked as a Termi or other .


No link pipe also which baffles me no pun intended as all the 2V Ducati's I have had use a link pipe.

If any of the 749 aficionado's out there can fill me in on reasons for the reason of two different diameter pipes .
Cheers
 

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10,218 Posts
The 749 uses an asymmetrical system. The different diameter pipes are correct. They did it this way to even out the pipe volumes so they didn't have to figure out where to put the extra pipe length coming off the vertical cylinder and could make one pipe longer than the other.

How about getting us a picture?

Edit: And someone with more knowledge than I can correct me, but I suspect the reason for not having a crossover is due to the different size pulses coming from the different sized pipes.
 

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small pipe - good for low rpm

large pipe - good for high rpm

If that's the case then you have one cyl. good for low and one good for high rpm.

they also run in different length and then propagate at the rear exhaust. (haven't seen the stock core yet but termi's looks like it is)

You if you know the exhaust temp. (which could varies along the way) you can work back what rpm that length are tuned to. Quite sure they are not the same for the different exhaust length.
 

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Yes the different pipe diameters are an attempt to equalize flow, smaller pipe is higher gas speed and big pipe will flow equal volume but at a slower speed. The attempt was to make up for pipe routing constraints. Your effective crossover is probably in the 100lb exhaust can that even when a termi did not shed much weight, hence the 749/999 breaking plenty of aluminum subframes.

The rusty pipe sounds like a D&D exhaust as they often (ever?) used mild steel instead of stainless like oem and everyone else.
Any pictures?
who made the can?
 

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Discussion Starter #7
It is a great little bike perfect for the missus with out an aggressive power delivery picked it up cheap from its second owner after he had it for 10 years , full 24k service 12 mth rego new tyres full service history original fairings included .
Will be adding tank grip and swapping out the OEM bars with their 9 degree downward sweep to some LSL 5 degree clip ons to make it a little more road use friendly.
A nice addition to the busy garage.
Ducati monster S2R1000
Ducati 1098s track bike
Yamaha R6 track bike
Ducati 749s
 
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