Exhaust, intake, jetting, drivability. summary?

[ovlovder]

So, I have spent countless hours over the past year reading about these topics here and elsewhere for the bandit. 

My question is currently, does anyone have experience or opinion on what is easier to tune, stock intake/exhaust, aftermarket pipe and modded airbox, pods, etc, what combination works best, I would rather a few less hp, if it was easier to tune, and keep tuned.

Currently, I have a 400, with the stage 1 jet kit from factorypro, and stock headers, with oem, and stock headers with a yosh slip on, three stock airboxes, and would entertain pods if they made it more drivable.

[tomacGTi]

Your advantage is that all of us on the board have collectively wasted hours of our lives dicking with these poor bikes and have written about it. Every change you make is a compromise somewhere else so keep that in mind.

Here's my take on the myriad of combinations my bandit has had over the several years that I have owned it. The biggest key is to jet to the changes and that modding the airbox is more sensitive to jetting than modding the exhaust (to an extent).

-Best drivability in town: stock (everything), with jet kit.

Not the meanest top end but good bottom and mid and the jet kit helps remove the midrange flat spot. Great poke around town, you'll be shifting before 11k because all it will be is noise above that. The stealthiest of all the setups.

-Middle ground: slip-on.

More noise and generally the same jetting. A slight bit more top end from the less restrictive muffler but tends to soften everything else a bit. If you mess with the airbox, you'll have to jet bigger to compromise. It will move the powerband of the bike up.

-Middle ground v2.0: Slip-on with modified header and airbox:

Jets about the same as an honest-to-goodness full system but the compromise here is the primary pipe size and weight. A well designed full system weighs less but will out-flow even a well gutted modified setup: I know, I have both. Paired with a modded airbox, it'll get you 70% of a full system without having to look for one since they're unobtainium anymore. Better top end but softer everywhere else. Don't expect to make power until at least 6k and at 8k it starts to wake up.

Has better bottom end and mid versus a true full system but as the revs climb (north of 10k), the true full system will win.

-Best power: full system, airbox mods

Best top end, good upper midrange probably the same bottom end but overshadowed by the stouter top end (way soft). You now have to definitely work the bike through the revs to get the meat of the power but it will leave a stock bike for dead. Certainly more temperamental the higher tuned the bike is.

4-2-1 pipes are more sought after because they spread the power better but most full systems you'll find for the little bike are 4-1 with the dreaded dead spot from 6.5k to 8k that is inherent in the design (you can't jet around it). The 4-1 is much stronger on top but it depends on who you ask.

For arguments sake: the OEM exhaust is a 4-2-1, the collector box has a divider plate that makes up the 2-1 part.

-Results, track tested anyway.

All of this will require a big step up in jets. I've gone from a 102.5 MJ to a 120 with everything else (carb-setting wise) remaining the same. It certainly doesn't make the bike a 600 but at least I can give SVs some problems now (they still have more grunt up top, especially modded). At some point it will be time to move on but for now I'm content.

The only step up from here is major motor work (big bore), flatslides or putting the bike on a major diet to get the weight down. Best thing to do really is to mod the motor to your liking and concentrate on the chassis and your riding. Outbraking people is more fun than out-grunting them anyway.

Hope this helps.

-Randy

[interfuse]

^^^ what he says. 

FYI I'm running a full system, airbox with the snorkel removed, factory pro jet kit setup almost exactly how factory pro recommends and I'm very happy with it. The key for me was removing old worn slides and needle jets.

Unfortunately I now ride like a grandpa and rarely take it into the fun zone. 

[ovlovder]

What is the recommendation for your setup from factory pro?

Jet size, needle position etc.

[ovlovder]

Thanks for all the info btw

[interfuse]

The settings they recommend for the yoshi system:
Stock filter
Stock advance
Stock pilot
float height 15 mm
2.5 turns on the fuel screws
Factroypro need 3rd clip from top
Main jet #100

With the stock pipe the the sample setting is:
Stock filter
Stock advance
Stock pilot
float height 15 mm
2.125 turns on the fuel screws
Factroypro need 3rd clip from top
Main jet #95

[ovlovder]

sweet, thanks.

[ovlovder]

Will the main jets from other bikes fit?  Searching Bike Bandit, the gs550ef uses a #100 main.  There must be interchange somewhere?

[ovlovder]

Or the b600?

[tomacGTi]

You need Mikuni large round mains. Small rounds will work as well.

You can generally buy them in packs of 4 if you search in the fuel section of most mail order houses.

What size do you need? I may be able to trade you for the tank stay.

[ovlovder]

Im thinking Id like some 100's, as I have an aftermarket pipe I may try eventually.  The setup I have is the factory pro stage one that was on the original bike, with k&n, and a 2bros slip on, has something like 96.5 mains I believe.  Have some stock 102.5's or whatever, would just like to start a collection.  Any reason to mess with pilot size on these bikes?

[interfuse]

I got my jets direct from a mikuni dealer. They were cheap and I bought a few different sizes. 

http://www.mikunipower.com/Distributors01.htm

As previously mentioned you want the large round jets

http://www.mikunipower.com/Catalog/MikuniCatalog30-31.htm

[pmackie]

You can try these guys as well...

http://www.jetsrus.com/