4 into 1 exhaust for max power?

[boontonmike]

Okay, I am sitting here with my bum knee and just brainstormng about how to set up my exhaust system. I am looking for max power in the high RPM's as thats how this build is going.

34mm CV flatslides, port matched the head to the larger CV carb boots.
K & N filters
Dyna 2000 with 2.2 coils, 8mm wires, will most likely advance the timing
Using the 550 cam on the 673 head for more high rpm duration

BUB 4 into 1 exhaust

Now my question is which would give me max rpm HP when tuned properly? No baffle, Baffle without packing, or Baffle with packing. I am most interested in baffle without packing to not have the bike ear pearcing loud but still perform great. Any other tricks or tips would be appreciated also.

[koolaid_kid]

I highly recommend packing the silencer. I tested my Kerker pipe before and after with a sound meter (yeah, I'm a geek). It lowered the noise level by 10dB, which means it is twice as quiet. It has a really nice sound, especially at WOT, but not neighbor-annoying like it was. And it scoots IMHO. For max performance I recommend finding someone with a wideband (a.k.a. sniffer) which will maximize performance for you. Plug chops, while they are adequate, will only get you in the ballpark. A wideband will put you on home plate.

[TheCafeKid]

It's really going to depend on a lot of variables. The size of the headers, mid-pipe etc really determine the added horsepower numbers more so than whether or it it has a baffle, packing etc. The larger the header tubes and mid-pipe the more the power will be moved toward the top end and the less midrange punch it will have. The top end rush will be fun, but for around town you may find it punch less.

These BUB systems are new on me. So I can't tell you what the pipe diameters are, how the collector is set up (stacked? Wedged? 4-2-1?) etc. I'd honestly suggest packing the baffle however and see what happens. A very good drag racing tuning buddy of mine found that in some cases pulling the baffle hurts performance. He had a bandit that ran faster times with the baffle on his Yosh in rather than out...

[isleoman]

Not an expert but would think you will get better low and mid range with the baffle and packing. A wide open exhaust will probably only benefit you at WFO throttle.

Since you seem somewhat interested in maintaining your hearing and not pi$$ing off John Q Public, I would say that's a second good reason for baffle and packing.

The third good reason is why alert Law Enforcement two towns over of your approach.

I have a Yosh on my 1100. It has baffle and extra packing. Several years ago I was riding next to a lake that was about 4 miles long. Lakes tend to echo noise. I crested a hill near the end of the lake and waiting for me at its base was a local police officer with radar gun in hand. He told me he could hear me coming while he was sitting at a boat ramp and had plenty of time to pull out of the parking area, set up on the street, and nail me. The ticket was for doing about 47 in a 35. Had I been on my FZ1 with its whisper quiet stock exhaust I could have blown by him at 75 with him never looking up from his nap.

[boontonmike]

I am actually going to be buying a wideband for tuning purposes. Had one on my previous turbo car and it was awesome. The bub exhaust has 4 into 1 and the all collect in one spot 2 over 2 then cone into a single pipe that is approx 2 inches, then goes to a megaphone and has a baffle with reverse cone at the end. It seems to be a pretty good size and design for the engine. The baffle is quite large, about 12"-18" long and the reverse cone exit tapers down to about the same size as the collector end. So i guess it would almost act as a straight pipe off the header just the megaphone portion is full of packing.

[TheCafeKid]

That's actually a pretty nice looking pipe. Wonder if they come in an 8v 750/850/1000 version?

Anyway, by the looks of it, I'm going to guess performance wise it's on par with a Vance and Hines of the day, or perhaps a Jardine. These were street pipes, not overly large on the tube diameters, and kept you from losing midrange power. Decent pipes but nothing amazing. The biggest advantage IMO was the weight savings over the stock system which was like a boat anchor.

You have to stop and think, the stock systems flowed pretty good. They weren't choked down by any means, except for the baffle. So if you had a stock 4-2 pipe it likely flowed nearly as well if not as good as or better than some 4-1 based on volume of air exhausted. Scavenging comes into play but that's above my "pay grade". But that pipe probably weighs half or there bouts of a stock system.

[boontonmike]

Jim has those systems for sale for a bunch of bikes in the for sale section. I paid 295 shipped for the header, megaphone and baffle. He found a stock of NOS somewhere. Fit was perfect and until I run it I can only go off of feel and fit. It seems like a great pipe. I just sold a 1000 Kerker and I like the design and fit/finish of this pipe better.

[boontonmike]

I mean I guess I don't want to have a completely gone mid and low end, but this is a 6 speed gear boxed 673 with pretty torque based sprocket setup and 1/4 turn throttle. I shouldn't be in the mid/low range for long at all. It's mainly going to be a backroad twisty toy only. My main concern is just not being completely too loud for the law reasons stated above.

[koolaid_kid]

That is a nice looking pipe. Like I stated before, packing made my Kerker half as loud (or twice as quiet), which I really appreciated, and I am sure my neighbors do as well. And I have 3 LEOs in my neighborhood, including 1 that I have to drive right by every time I exit or enter my subdivision.

[koolaid_kid]

I use an Innovate LM-1 wideband with an exhaust clamp. It does take up a bit of room; I was unable to fit it into TCK's pipe. On my Kerker I just remove the baffle and it goes right in.
A stainless O2 bung is sometimes required, which is what I have on my turbo car.

[boontonmike]

im going to get an AEM and weld a bung in after the collector. its 160 on ebay with tge O2 sensor. I like the AEM cause its a round guage

[koolaid_kid]

AEMs are fine if you want a permanent installation. I have a friend who installed a LC-1 in his car, it seemed to me to be more of a light show than anything else, but he seemed to like it. I use my LM-1 on lots of vehicles and for multiple purposes, so it makes more sense for me. As long as you use it correctly to tune it (and you will), you will be extremely pleased with your results. It is really easy and straightforward and does not take that much time. Your results will be spot on for all the carb stages, no guessing required. Hopefully you have already researched the correct AFRs for air cooled motorcycle engines, which are different from water cooled engines.
And then you can sit back and chuckle at the plug chop threads.

[boontonmike]

Never used an LC1 or LM1. I had the AEM and liked it because it has the number readout and than a color coded digital dial guage around so it would be easy to see peripherally if you were spiking lean or rich while road tuning. I don't mind the more perminant setup. They keep coming down in price so eventually any vehicle I want to put one on I'll buy one for it.

I did some more reading on AFR's and have a pretty good idea of what to shoot for. I know that it seems to be a general rule of tuning rich for air cooled. Wondering how the oil cooler and timing manipulation from the dyna 2000 would effect that? I also don;t mind tuning on the rich side in warmer weather so that I don't need to rejet when it cools down outside.

What kind of spark plugs are the go to choice?

[gearhead13]

I have/had a red LC1 gauge on my bike. Its still there just not hooked up. It is VERY hard to look down at the gauge when you are WFO. It works great for idle and part throttle. With mine I am able to hook up a laptop to it, carry it on my back and go riding and check the numbers later.

[TheCafeKid]

Never used an LC1 or LM1. I had the AEM and liked it because it has the number readout and than a color coded digital dial guage around so it would be easy to see peripherally if you were spiking lean or rich while road tuning. I don't mind the more perminant setup. They keep coming down in price so eventually any vehicle I want to put one on I'll buy one for it.

I did some more reading on AFR's and have a pretty good idea of what to shoot for. I know that it seems to be a general rule of tuning rich for air cooled. Wondering how the oil cooler and timing manipulation from the dyna 2000 would effect that? I also don;t mind tuning on the rich side in warmer weather so that I don't need to rejet when it cools down outside.

What kind of spark plugs are the go to choice?

Plugs? NGK all the way baby. Don't stick no chumpion crap in there.

I can't recall if your bike uses the B8ES stock or D8EA. Most of the 8v bikes used the B8s and the 16v uses the D8, but if you're using the 650 head I think that was an oddball and used the D8... 550 8v used B8. If you run it on the slightly rich side you may want to use the B7 (or D7 depending on what yours uses) as its a hotter plug. On my 1100ES I used the D7 and i was running larger carbs pods and a jet kit and had perfect colour on them. Try the stock plug temp first though.