Exhaust Blues

discussion about the 750 Sport and '89/'90 900SS, which share many mechanicals with the Paso series
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Fireypete
Posts: 36
Joined: Sat Aug 23, 2025 5:24 am
model: 750 Sport
year: 1990
Location: Australia

Exhaust blues

Post by Fireypete »

I have a set of genuine 750SS exhaust cans. Thought they would fit my bike (had high hopes!). It would appear the 2 into 1 system fitted is a home made job. Phuck I say! Option would be to take the bike on a trailer to an exhaust shop and see if they can fit it. The header bolts are rusty, they dont look real good which brings the issue of them snapping if I locate an exhaust sytem. Any ideas?

SORRY, RE POSTED IN THE SPORT 750 SECTION
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Duc Exhaust.jpg
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Last edited by Fireypete on Sun Sep 28, 2025 10:56 am, edited 1 time in total.
Fireypete
Posts: 36
Joined: Sat Aug 23, 2025 5:24 am
model: 750 Sport
year: 1990
Location: Australia

Re: Exhaust blues

Post by Fireypete »

Oh, being a USA import the headers are smaller diameter than the rest of the world. So, finding a set in Aus wont fit... I can see why the bloke was keem to sell :(
Mc tool
paso grand pooh-bah
Posts: 1984
Joined: Wed Dec 05, 2007 12:35 am
model: 906 Paso
year: 1990
Location: Riverton New Zealand

Re: Exhaust Blues

Post by Mc tool »

If I had a choice I would def go for the bigger ones . I used to know a guy who ran a Ducati workshop and raced belt drive 2 valvers and he swore that the 1st thing to do was upsize the header dia and re-jet
Im understanding that the 2 into 1 is a bit naff . Do you have to fit some tested or certified exhaust to get the bike road legal or are you just looking to go back to original ?
Do you have a Mig welder ........its not that hard to make your own headers out of exhaust bends .
If the rusty studs you mention are the ones in the head it would pay to get them sorted before they break . Give them a good wire brush up and see just how rusty they really are . If none of the pitting is deeper than the bottom of the threads you may be ok ......but .....some peeps loose sleep over things like that.....not me :roll: :lol:
I wish I was young again............Id be heaps smarter than last time
Mc tool
paso grand pooh-bah
Posts: 1984
Joined: Wed Dec 05, 2007 12:35 am
model: 906 Paso
year: 1990
Location: Riverton New Zealand

Re: Exhaust blues

Post by Mc tool »

Fireypete wrote: Sun Sep 28, 2025 10:07 am Oh, being a USA import the headers are smaller diameter than the rest of the world. So, finding a set in Aus wont fit... I can see why the bloke was keem to sell :(
How sure are you about that Pete ? (Im not :) ) The flange is the same size and apart from that they are just slightly bigger dia . I would have thought that the biggest issue is that you would have to modify the ends to suit the rest of the system .
906 and 750 have different length stroke so the heads are further apart and the headers are not interchangeable .
I wish I was young again............Id be heaps smarter than last time
Fireypete
Posts: 36
Joined: Sat Aug 23, 2025 5:24 am
model: 750 Sport
year: 1990
Location: Australia

Re: Exhaust Blues

Post by Fireypete »

Hey Mc tool, yep the road worthy needs a standard pipe. They take photos of it and send it to Vicroads Also vicroads want to inspect it to see if it needs a specific engineering certificate for Victoria its been done in QLD but.... PITA really. I'll get the bike back together and take it and the standard exhaust to a exhaust shop, they will be able to make it fit. When I get a RWC and club plates Ill think about a 2 into 2. Have to get it made.
Fireypete
Posts: 36
Joined: Sat Aug 23, 2025 5:24 am
model: 750 Sport
year: 1990
Location: Australia

Re: Exhaust Blues

Post by Fireypete »

This is what I have. Part number 57310221A
This slips into the header pipe. The header has an external dimension of 45mm
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IMG20250929114922.jpg
IMG20250929114922.jpg (44.94 KiB) Viewed 859 times
Fireypete
Posts: 36
Joined: Sat Aug 23, 2025 5:24 am
model: 750 Sport
year: 1990
Location: Australia

Re: Exhaust Blues

Post by Fireypete »

I have a fairly basic mocrometer and I'm reading 38mm I reckon if I go bigger they wont fit onto the cylinder head. I'm gonna jump the fence an see if the Paso lads know if their headers are 38mm. A paso system should fit
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