76a exhaust options

[morris147]

just curious as to what options we have for exhausts and which ones actually make power!

As far as i know:

Standard
sandy bike spares
autorimessa (Only ever seen photos, haven't seen any power figures)
Yoshimura (Again, yet to see a full system or power figures)
RPM (as aboth)
Yamamoto A-spec

And theres the route of a custom made system.



What other systems are available, or "were"?

[moforockband]

I'm no aftermarket exhaust guru, but I have been dabbling with the 76 exhausts fitted to my 73.
The best results I had out of the 400 was with the standard Suzuki 4 into 1 mild steel. Low to mid 60's hp, and did ok in club racing. It made nice power everywhere, but that head had been mildly worked on back in Japan.

The problem with some of these stainless manifolds on the market is that they have welded the collars from the inside! This makes the pipe look neater, but restricts the gas flow. The welds on mine were from 3- 7mm thick inside the pipe. I've since rewelded the collars on the outside and ground the inside welds back.
The welding looks to be the same method of construction with the Bla*k Widow set on sale currently.

29mm inside diameter with a pipe wall thickness of 1.5mm, and ending with a std 2" outlet is the rough way to go if you're thinking of building one.

[morris147]

I noticed that with the set of sandy bike spares headers i have, on a "customer dyno" it was giving 64.5bhp and only 54 on our club dyno. I now run a yamamoto system, jetting still needs some work but were around the 63 mark on the club dyno with 122.5 mains. Im very interested to see the gains from the Autorimessa pipe set up, as from what i gather that was the "Race Kit" option?

I have a kit loom, and the faux airbox covers. I have seen photos of the kit airfilter and cdi but no confirmed power figures from a "Kit Spec" 76a.

[moforockband]

Why the large difference between the dyno's? different manufacturers, ie dynopro/dynojet??

[morris147]

Unsure about the deficit. The club dyno is used for compliance runs for certain classes so i will be going off the results of that dyno.

[moforockband]

What do Sandy's headers look like? Mine make good mid range power but not so much up top. I've modified mine internally to increase high speed gas flow. Dynojet dyno's are all over the place. My bike will make 60 on one and the 54 on another?
I'll download a couple of piccys once worked out how to do it!

[moforockband]

[morris147]

I'll grab some photos of the sandy bike spares system later or tomorrow.