Stock exhaust performance

[hondaror]

Sounds like they ran pretty good on the bike they were on. A rich running bike runs quite a bit leaner when you put pipes on. Jetting right really helps the cause as well. The crud around the silencer should be Sandy brown and a bit gritty.

[jumjum01]

Update on my modded 1UA exhaust. I made different stinger "inserts" with different diameters. The baseline 24mm stinger combined with a free flowing exhaust killed the power, I guess due to not enough back pressure. By decreasing stinger size the bike now pulls so hard it makes the clutch slip in 2nd gear. EGT temp didnt increase significant. I allready fitted bigger FZR clutch plates, so I guess there is no way around stiffer clutch springs
Bike will by dynoed as soon..

[kpke]

[(F5)]

Well that's surprising. . . . Oh wait, it's not. Good on you for objectively testing. You can mount every 2nd stiff spring. That's what I did on my original.

You could also lengthen the lever on the case. I think I did mine about 8mm or so on my bigbore bike. I might have ovalised the cable hole to get a better angle. So long ago.

[crogthomas]

Nice work. I've just done exactly the same to a set of 1UA exhausts, except my welding isn't as neat, so it's good to see I haven't wasted my time.

It's worth mentioning that the broader FZR clutch plates won't increase the clutch torque capacity, the only simple option is stronger springs (or 3 stronger of 6 as F5 says). The FZR plates might increase the life of the clutch though.

[RZtuner]

Jumjum, when you just fit FZ6 fiber plates the clutch is still compromised by the OEM narrow elliptical steel plates. They are a mismatch. In order to take full advantage of the extra friction area of the FZ fibers you also need to fit full width steel plates to match. The FZ6 steels are too thick, use Barnett steels for the Banshee.

https://redlineracing.biz/shop/clutch-p ... a-banshee/. A new set of stock springs work fine with this set-up.

I use this set-up on my land speed race bikes and have never had clutch slip.

I'm not a fan of fitting heavy duty springs, nothing worse than riding a street bike with a heavy clutch. I once bought a motor off a guy who had the 3 spring mod done to it and found the bottom punched out of one of the spring cups on the pressure plate. IMHO there's really not enough material there to support the spring load reliably. Take a good look at your pressure plate, the metal is really thin at the bottom of the cups. Dunno, maybe it was a casting flaw? but it failed, so definitely think about that.

Hope this helps.

[jumjum01]

RZtuner, thanks for tip on clutch steel plates, I just placed an order for 6 Barnett plates

[jumjum01]

Well, time for the verdict... bike was dynoed today. Did some runs with different stinger inserts ranging from 16 - 24mm diameter (20mm long). 16mm was the clear winner. The stinger inserts made a difference in power from 7500rpm and up. Below 7500rpm, no real difference in power output.
Blue line on dynosheet is baseline with cigar exhausts. Red line is modded 1UA exhausts and 16mm stinger insert. Since baseline dyno the bike was fitted with new pistons and squish set to 1mm, so the differences in power output can be affected by this.
But my conclusion is that the 1UApipe is probaly more fun, since its a street bike and having the power come on much ealier rpm vise will make a snappier acceleration. We tried different fuel, timing, ypvs settings on the dyno but the 1UA refuses to make power past 8500rpm and falls on its face. I guess it comes down to exhaust design.

[Evans Ward]

Impressive results especially for the cigar shaped exhausts! I agree, the cigar stockers will add to the sleeper effect both in looks and sound.