4 into 1 exhaust

[Mr Jake]

Gentleman,

I have a question for all the riders that have made the switch from stock exaust systems to the 4 into 1 configuration. I have heard a lot of hype about horsepower increases from people selling the 4-1 systems, but haven't heard a lot from people who have bought them.
What are the chief advantages of a 4-1 system? Is there actually a noticeable increase in performance? Is it due to a decrease in weight or does it actually increase power? Or is it the change in the way the bike sounds that is the reason that people switch?

Let me know what your experience has been.

Jake

'80 SG

[Madness]

4 into 1

Jake,

I had to replace my rotted pipes on my Midnight earlier this summer. I had a used set of Kerker that I had picked up on eBay. I haven't ridden it enough to really give you an answer on increased hp. Does seem to have lost just a bit in the low end, but once you get past that....Hang on!!! Seem like hp increased, but YMMV. The Kerkers are pretty loud when you get on it in the upper rpm's. So far I love the sound. Probably will need ear plugs for any extended riding.

Jim

[tsears]

4:1 - loud and faster

Hi Jake,

I replaced my stock exhaust on my '80 SG because it was rotting out. I installed a 4:1 Jardine. I got an increase in performance (incremental - 5-10%), and the bike is now a lot louder. I don't like all the noise, and am saving for a MAC 4:2, which may also allow for an oil cooler.

Tim

[Mike Hart]

Hi Jake, and welcome.

The 4-into-1 will give a bit of hp increase due to increased exhaust flow, but to get the most out of it you have to also increase the intake air flow, either with individual filters or a hi-flow K&N replacement filter with some additional holes in the airbox, and then increase your jet sizes.

For info on that, you can see the Jetting Recommendations Jetting Recommendations tip.

As Jim said, you will lose a little on the low end, but will gain in the mid- and upper-range. Won't hurt gas mileage either!

[strom]

Well, I have a 4in1 exhaust... the short edition (u'll understand when I scan the photos) with a single marwing.
I'll try a 4 into 4, when the beast starts... a friend's got it... 4 marwings :P
Anybody got any earplugs I can borrorw?

LP

[Mr Jake]

Increase in flow?

>The 4-into-1 will give a bit of hp increase due to increased exhaust flow...

This is one of the things I don't quite understand yet. I don't deny that it is true, but how can the bike have increased exhaust flow when it has half the exhaust pipe area (of the original 4-into-2) and an increase in back-pressure?

And I have another question for you. That jetting tip thread didn't mention any adjustments for high altitude. In Denver here, I already have to lean it down to compensate. I am not sure I would be able to go up to a larger jet size.

Mr. Jake

[Mike Hart]

short answer: better scavenging (actually less backpressure)

altitude: I'll let somebody who lives at altitude answer you more specifically, but yes, your increases per the jetting tip would be offset by your altitude.

Are you running stock jetting now? Does it behave like it's rich? Plug color?

with 4-into1, and filter &/or airbox mods, maybe you wind up with stock jets, that would be cool.

Also, Gary (sixtysix) posted this carb link in the Links forum, has a chart that should help.

[Mr Jake]

jets and plugs

Originally posted by Mike Hart

>Are you running stock jetting now? Does it behave like it's rich? >Plug color?

As far as I know (I haven't changed what the previous owner had in there and he didn't know anything about it) I have the stock jets in now. I tuned it by color (Colortune kit) and ear till I got it where it seemed to behave best. It doesn't misbehave or backfire but the plugs do have a little bit of carbon on them when I check them. They are not dark black but they are darker than they should be. I just put in a K&N replacement (oval configuration) filter in and haven't checked the plugs since. That should lean it out a bit but maybe I should make some holes in the airbox as well. Frankly, I haven't noticed any difference with the K&N but it could be that I need the additional air holes. What size/how many holes do you reccomend?

Thanks for the tips- It is great to get the chance to discuss this with somebody else.

Jake

[Mike Hart]

Haven't done that myself (drilled airbox). The bikes I'm familiar w/ have the indiv. filters. Jake, the Search feature works good, you could put in 'airbox' (no quotes) and see what you get!

But, there already happesn to be a thread on the subject right here in XS/XJ Discussion forum!

[skids]

Jake I am in Denver (Arvada). I have a K&N Washable. 4into1 Jardines. 1978 Model E. New 130 mains, old 42.5 pilots, 210 air pilots. At 60 mph, 37 mpg!!! No midrage missing. Good torque all around. 1.5 turns each mix screw.

Note that I have another xs11 with 4-1 Jardines and the same filter. It is an 81H with 78 carbs on it. I tried the same jetting and it was rich at midrange. I lowered the pilot jets to No. 40's and then I dropped the needles one notch and it helped, but it is not quite adjusted right yet. I can't explain the differences!

[nwilley]

I installed a SuperTrapp 4-1 to replace the old stock system. A few impressions...1] Not as quiet, but sounds neat 2] Tunable for low/high end performance.

Mostly I went with the SuperTrapp because it was in good shape, and I couldn't pass up a deal!

[Mr Jake]

more on exhaust dynamics

I dug up some info on exhaust systems on the XS850 Triple site.
I found it interesting. Maybe you will too.

http://w3.one.net/~ryanr/triplesite/exhausts.html

Mr. Jake

[procamper]

hey madness--

does that kerker work with an oil cooler?

[Madness]

Procamper,

Don't have a oil cooler on Twisted, so I can't tell you for sure. I know I need to pull the pipes to change my oil, and cannot use my center stand.

[irb9494]

Kerker

I recently purchased a Kerker 4 into 1 for my SG. The gentlemen I purchased it from emailed a photo of the exhaust installed on his bike so I could get a good look at it. He also had an 80SG and it did have an oil cooler installed. It looked as if there was no interference with the oil lines and the headers and enough space to remove the oil filter housing.