New Owner


New Member
Greetings Everyone:

I've recently purchased a 2017 RC390. Bike has 5k miles, a full high-mount Werkes exhaust with PCV, tail tidy.


I've been riding bikes since I was 12, my first bike being a Honda cb160 back in 1970. Since that time I've owned more than I can count, everything from 2 Stroke Aprilia 50s, 125s and 250s to a prototype Ducati Supertwin (one of about 6 built). Through all that time I've maintained a love for small displacement bikes. My perfect bike would be a 50 hp 250 lb sportbike., and a few years ago I thought of building a "Moto 450" bike via a kit but never got around to doing so.

In 2008, when Kawasaki first offered their new generation 250r I bought one with the intent of doing everything possible to decrease its weight and increase its performance. That's it below:
To that end I did the following:

-ported/polished the heads
- replaced the stock carbs with oversize Keihin 32mm carbs with stage 2 jetting
- ignition advancer which also overrode the rev limiter allowing the bike to rev up to 14k
-12.5/1 hi-comp pistons
- balanced a lightened crank
- full ti GP exhaust
- full suspension upgrade by Traxxion Dynamics, including Penske shock and reworked forks
- forks moved up in triple clamps by 25mm ans clip-ons mounted on forks above triple clamp
-Galespeed Type R Forged wheels w ceramic bearings
- 520 chain conversion
-lithium battery
-drilled rotors
-braided lines
And a bunch of other things I'm probably forgetting

The point of it all was to make the lightest, fasted, best handling little 250 possible. Needless to say, I threw stupid money at it, but it was all a lot of fun and the bike is an absolute blast to ride.

I note all of this because I'm intending to do the same with the RC390. To that end, I've done the following:

- aluminum rear 43t sproket
- loaded a custom map for the pipe
- opened the airbox and K&N
- lithium battery

While I haven't had a lot of time on the bike, I really like the bike as it is now and don't intend to do much more. What I'm thinking of in the future is to concentrate on reducing rotating mass, which, in my opinion, is the best bang for the buck. Specifically, I'm thinking of drilling out the back rotor, replacing the front rotor with a 320mm Galfer Wave rotor and possibly going to a standard non O-ring chain. All told, that's about 4 lbs of rotating mass removed, which is significant for a 43 hp bike.

I'm also contemplating the BST wheelset, which, if what I'm reading is correct, is about a 14 lb reduction over the stock wheels, which is a significant amount of rotating mass taken off in one shot. I'm interested in hearing from anyone who has experience with the BST wheels on the RC390.

In any event, thanks to everyone here flor all the great information on the site. It's been a great help to me and hopefully I can add to it in some small way.

Cheers, Tim


Premium Member
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I'm interested in hearing from anyone who has experience with the BST wheels on the RC390.
I have a little experience so far, having done two track days so far on them. You give up a little of the weight saving because the rear takes a 160 tire, which generally weighs a bit more than the stock 150 - or the 140s that some folks use.

That said, and considering I have only about 40 track days on the RC under my belt, I feel noticeable, but not radical, improvements in acceleration and braking, and turn-in.

On my 1.8-mile track my typical lap time dropped immediately from about 1:41 to about 1:37.

I would say that bang-for-buck is not high for this expensive option, but now that the purchase is behind me and the money forgotten, I am very happy to have the wheels. And they are beautiful.