Categories: all aviation bicycle gadgets misc motorcycle theater

Wed, 15 Sep 2010

Thoughts on racing the Ninja 250

My race-day report earlier didn't really address some of the Ninja 250-specific stuff I was pondering.

The bike acquitted itself pretty well. The suspension upgrades (.95 kg/mm springs in front, '08 stock shock in back, cranked to full preload) were definitely worthwhile, although I really need a stronger spring in back. The back end was wallowing a little bit -- not a lot, but enough that I was aware of it. The front springs are so stiff that even at full preload (a poor-man's stiffer spring), the rear shock was a bit mushy feeling. Damping was fine on both ends, or at least I wasn't aware of it. Unfortunately, I don't think the '08 shock can be resprung, so if I want to solve the problem, I'll need to find another way of doing it.

The stainless steel braided front brake line was definitely worthwhile, and I'm sure most of the bikes that make it out next year will sport them by the second session. I already knew this, but it was nice to see on the track too. Between the suspension and the SS line, my bike was the most race-ready of those that went out.

Tim had BT-003 tires on his (cheetah!) '09 bike, which was to his advantage when the track was dry, but left him behind me (a position he never sees, except while passing me, normally) for the first damp-track practice session. He said his tires were "like ice" on the wet track. Phil, running GT501s and stock suspension, said that my form was good enough around turn 2 that I was pulling away from him in the practice (and I was going pretty slowly, in my own estimation, not trusting my tires too far).

The BT45s I had on were fine, but I noticed particularly in the entrance to turn 3 that I was chirping the rear tire every time I downshifted. It's not a big deal, as I never have to downshift while leaned over very far, but I have a feeling that the relatively hard center compound on the BT45s is contributing to that. I'd like to put stickier tires on the bike, and I've emailed Pirelli (requesting the advice of their experts, according to the web form I filled out) asking their opinion of the MT75 vs. the Sport Demon. I'd rather go with the MT75 if they're equivalent or better, as the smaller tires will be better handling, and will noticeably reduce rotating, unsprung mass. Interestingly, after my rides on Sunday, I was able to clearly see the line seperating the hard center and soft side compounds on the rear tire.

I found myself holding back through turn 2 (where I feel like I'm getting pretty good, with the new pavement, and as my crash there recedes a bit into history), unsure of the grip my tires would actually have. I know I wasn't pushing them too hard, and I can go further there, but allowing myself to do it is a real challenge. I still pussy-footed through turn 3 and 4, and as always, I know I can go faster through there. I know how to do it, I know what the good line is, and I just can't get myself to actually do it. This isn't a Ninja vs. CL issue, it's just me.

Having the greater power of the Ninja was very pleasing to me. I didn't even take out my airbox snorkel (something I think everyone else did), and I was doing well down the straight. If I follow through with my plans to get a Muzzy exhaust (single-sided, therefore lighter, and theoretically flows better) and yank out the airbox, I should be able to add a little bit to top-end power, at the expense of midrange. It's a compromise I'd never make on a street bike, but for a race bike, it looks pretty attractive. I'm going to get the bike down to a dyno before I make any changes, and see what happens with and without the snorkel, then take further dyno runs to figure out jetting, and see what kind of gains I actually make (I don't expect much -- I honestly just want to get the weight reduction; one ninja250.org forum poster said the stock system weighs 20 or so lbs, and the Muzzy weighs 5.5).

The Ninja 250 is a much physically larger bike than the CL175. I always knew I fit on it better, but it was pretty dramatic how clear that was when I immediately leapt from the Ninja to the CL on Sunday. The CL felt weedy and insubstantial, where the Ninja had felt solid and reassuring, at least as far as my physical contact-points went. The Ninja was obviously suffering a bit from weight: where the CL175 feels stiff and solid on its suspension primarily because it weighs very little, the Ninja felt like the forks were flexing a bit. I may build myself a fork brace to try out, but I can't see spending the $100+ the commercial braces seem to command.

I think I'm going to get some of that Stomp Grip stuff (nubbly grip tape that goes where your knees hit the tank, to give something to hold on to), as I think it might help increase my confidence in hanging further off the bike, and will probably help me relax my arms a little bit in some situations. It's a relatively cheap investment, and seems worth trying. I have grip tape on my street Ninja, and like the effect, although it's really just a friction tape, where the Stomp Grip is actually sizeable nubs sticking out. I've never bothered on the CL, because the tank is so skinny I can't really grab it with my knees.

Overall, I was very pleased with the Ninja 250 racing experience. Sure, I came in last, but I was up against dramatically more skilled riders. I was on a bike I enjoyed much more, and it definitely seems like it's worth pursuing for next year.

Posted at 00:11 permanent link category: /motorcycle

Categories: all aviation gadgets misc motorcycle theater

Written by Ian Johnston. Software is Blosxom. Questions? Please mail me at reaper at obairlann dot net.