Power Upgrades

[Highc5555]

thank you. this is most certainly more info than i have found anywhere else. do you happen to know if the vn1500j block is the same as all other kaw 1500s? surely somebody has built a performance motor with one of these kids. does kawasaki have a performance division or any speed shops dedicated to kawasaki motors?

[chief]

I know many people have upgraded the performance of their 1500. Some of the resources/components they used were from other bikes and local customizing. Suppliers aren't as readily available and the kits that used to be available may no longer exist.

This is a quoted post made by ROK (from the old DRF forum).  He did a lot of mod work to his bike.

From: Rok (rokkinhorse)9/14/10

Bro,
You can pretty much go as wild as you want with engine upgrades, the difficulty IMO is with bumping the compression.

There's so much ignition advance that these aftermarket pistons, pretty much all of them, will at the very least require an ECU change to a Classic 1500 box.

The two boxes are near identical but the Drifter brings on more ignition advance and faster than the Classic.

If you're just in the market for a cam changeout, take a gander at these guys: http://www.webcamshafts.com/ (Editor Note: this company is still around but don't know what they have for the 1500 nowadays.) You'll find the grind for a Kawi 1500 that enables the use of stock valve springs. They also offer a service to modify and upgrade the rockers.

From what I've been told, you have to be very careful of binding the stock valve springs with too much lift OR by altering the rocker ratio. The more lift you put into replacement cams, the more work the heads will need to accommodate that lift. Pistons might also have to be relieved, especially if you keep to the same or similar exhaust duration/overlap.

If money were no object and I could do anything I wanted with my Drifter's engine, it'd be outfitted thusly (100+ cubic inch displacement):
1. Nomad 1600 crank, gearbox and electricals.
2. Mean Streak heads, intake and injectors
3. JE pistons, 11:1 ratio (note: JE makes ALL the aftermarket pistons for Thunder, Muzzy's , etc. The casting and piston characteristics remain the property of the vendor)

EDITOR NOTE:  Thunder MFG still exists but I don't think they produce performance products for the 1500. Muzzy's is gone. JE Pistons may still make pistons which will work on 1500s.

4. Custom-burned aftermarket ECU, to maximize the mods without detonating the engine to death., i.e. modified spark curve. There could be several maps and spark curves that could be changed at the flick of a switch to match the type of riding you plan to do. Have access to racing fuel that's 106 octane or better? You could have a configuration in the controller to make it work.

Another consideration is the max RPMs of the stock ECU; at 5750 RPMs, most of the head mods that could be done are just beginning to work. Thus, the custom-burnt Engine Control Unit. (starting at $2500).

The good news there is that you can also control the ignition, something impossible to do with a Power Commander or other commonly available controller.

Head porting, polishing and flowing would somewhat be wasted on an engine that will only spin <6000 RPM. A simple cam change that would put some of the HP down lower would be money well-spent IMHO.

Good Luck! If you research any of this, please post it and share what you find. Disclaimer: The above is opinion only, based on my own very limited understanding. Corrections accepted:-)

Rok

[Highc5555]

Has anyone installed a full stage 4 kit on their 1500? Including: intake/exhaust; cams; cylinders/pistons; hi-flow heads/throttle body. I am not having much luck finding resources on builds, components, etc.