Anyone race an RS125 and RC390

Does anyone have experience with both a 125 and an RC390? I'm curious how they compare.
I suspect that any competent rider on a 125 will easily run away from even a very good rider on a 390 in a race. That's not what I'm asking.

Rather, in non competition terms, like a track day, how does one compare to the other? Just the simple pleasure of riding a small, slow, light bike to the limit. You know, fun.
Can an RC (or Duke for that matter) go around corners reasonably well on stock suspension or does it need to be fettled and upgraded?

To me a 125 was the pinnicle of obtainable motorcycle racebike perfection, but limited time, money, flexibility, fitness, etc etc rule one out for any future forays onto a track.
KTMs can be found for a song but are they just grocery getters in fancy clothes or legit lightweight track bikes?

Thanks

 

I haven’t ridden either but do have a 125 2 stroke in a Aprilia RS50. I think it would be like driving a Prius Vs a formula one car .

 

It's awful. I used to race an Aprilia rs125 and r6 back to back. The 125 in single cyl category made me a better rider, but holy fck it also made me angry. Unless your field/category consists of the same zero torque all corner speed machines, you will be angry and being held up in every/second corner. Want to pass someone, no rush, it will take two laps to get that passing move lined up after you lost all momentum when some jackass parked their motard it in the apex. Arrghhh, flashbacks.

 

@motion has raced/ridden both I believe.

My son raced a RS125 and/or Moriwaki for 3 years. On a track day, I don't think you will enjoy the RS125. We were lucky enough out here, that the organizations would let the boys ride the 125's in the fastest groups, because the slower groups are really tough with guys parking it in every corner and then motoring on past you.

My son loved racing the 125 and the Moriwaki, he didn't enjoy track days on them. Having said that, I'm not sure a RC390 would be much better, but at least it would have the torque to get you our of a turn if a slow guy on a 600 or 1000 parked it in the corner. With a 125 that is really tough if you can't keep up your roll speed and stay on the pipe, you end up passing the same guy back and forth multiple times....but he is having a blast thinking you are racing with him and you are frustrated, because he keeps messing up your corners.

I really think a SV650/R7/Aprilla660 is much better for track days. Not sooooo much power to scare the crap out of you, but enough that once you learn how to ride, you can still get passed the 600/1000 that park it.

Racing wise, I like the Ninja 400/KTM390 class bike, and if I were going to race again now, I would want one of those or a Krammer.

 

I forgot to mention 125's are very easy to work on, but unfortunately that is because you have to work on them. Especially when racing, we had to put a piston in every weekend or every other. Rated for 300 miles a piston. 1200 miles per crank, as I recall. On a Friday/Saturday/Sunday race weekend, we would check to make sure the piston wasn't pinching the ring as the ring land starts to collapse, every evening. Originally that meant head and cylinder off. After time I learned how to check it through the exhaust port, but it is just a bunch of tedious work that gets old after a few years. The last 5-10 top ends my son did, as I taught him how, and while his buddies were playing on a Saturday night at the track, he had to do the piston swap, before he could go play. He could probably knock it out in about 20- 30 minutes, so it is easy and his smaller hands and better vision helped too. LOL

If you run track days only and run it a little rich, we were trying to make competitive horsepower, you probably don't need to monitor all that stuff, other than replacing pistons every 300 miles or so.

 

Yeah I used to race a TZ many years ago. It was perfection. But just for the occasional trackday giggle I don't want another GP bike so wondering how a litle RC390 would compare on track just on the basis of fun light flickable low power little bike.

Kramer seems ideal but a bit spendy for me

 

I have an RS125 with a CR85 engine, so maybe 20hp at the wheel and can barely hit 90 on the straights (hopefully getting some better gearing soon).

It is a blast to ride on larger kart tracks and on full size tracks when you have a clear path. Doing track days on it can be scary and definitely frustrating at times for exactly the reasons Boman listed. Very few people at a track day will understand the corner speed and lines that you need to run to keep such a bike moving, and they will stuff you in ways that can get pretty sketchy. At least with a real 125 you have better acceleration and top speed that fits better on a large track. My little bike is largely out of place.

I also ride a Ninja 300 (and former 250), which is a bit more compatible with faster bikes since the difference between top speed/acceleration and corner speed isn't as drastic as on my RS. Other riders understand them better (but still not always great). I've never ridden a KTM 390, but this size bike is still a lot of fun and will help build skills. Riding in the fast track day group I don't get many opportunities to pass, but it is great fun staying glued to the back of the larger bikes.

 

I race a 125, and generally avoid track days. As others have said, the back and forth with 600s and 1000s parking it in the corners then passing on the straights is tedious at best. What really concerns me though is the speed difference on the straights. I hate sitting there with the throttle pinned in 6th just waiting for someone on a 1K to go blowing by 6 inches away 50mph faster than me. I just don't trust people at track days enough to be comfortable with that. An RC390 would be even worse from that aspect.

 

Yeah, I ended up riding my RS125/85 at Road Atlanta, of all places. That is not a track for small bikes in general, let alone something that tops out at Back to the Future speeds. I did 3 sessions on it due to my 250 having a mechanical, and liter bikes were blowing past me at literally twice the speed I was going. It was sketchy as hell, so I would move all the way to the right side of the track immediately after T7. I have to cross the track at some point to setup for T10, so I figure do it at the start of the straight where people are going 20mph faster rather than +90mph at the end. And even then, some people were still buzzing me at 6in away. :/

 

Any of you guys with RS125/85 or RS125/150R's wanting to sell them? At one time while my son was coming up, we had different bikes with RS chassis with a 65, a 85, and a 150R, I wish I would have kept the 150R for me to ride now, but I always need the money to buy the next bike. The first one was a TZ85 and I rode that one, somehow all that weight on my right hand and I must have pinched something, because that hand tingled for a few months after riding it.

 

PM Sent

 

Agree with all the guys saying a 125 is a lousy TD bike. Disagree that a 390 (or R3 or N400) is too slow to be on track with bigger bikes. Best bet is to buy one already prepped, most importantly suspension sprung close to your weight.

 

A prepped Ninja 400 would probably be my ideal TD bike. I like my 300 a lot but certainly wouldn't frown upon another 10-15hp. The only concern I would have for the 390 is reliability. Maybe they haven improved recently, but I seem to remember they were somewhat prone to engine issues.

 

An RS125, as others have said, is not a good trackday bike.

I like my bikes soft, so I liked my RC390 Cup bike quite a lot with the stock suspension. They are rather strangely tall, but I think they're great track day bikes. Unless you're an advanced rider or very heavy, a stock Cup bike would be fine for you. I wouldn't recommend a street bike unless you're a beginner.

Stay in the intermediate group. Unless you're on a tight, small track, the closing speeds from big bikes that might have inexperienced riders on them is really just not worth the risk.

 

I'm not crazy about intermediate group on a small bike, tbh. I get the closing speed rationale, but I find that in intermediate the big bikes still buzz me on the straights since intermediate and beginner group riders can buy liter bikes as much as anyone else. If people are going to fly past me, I'd rather they be better, more experienced riders who can make a clean pass and keep moving away.

 

I'm surprised I'm first to say... fuck track days- get an R3 or N400 and go racing. Endurance if they have it where you are.

 

I rode an RC390, Ninja300, and Ninja400 back to back around Laguna, all prepped for club racing. I like the chassis on the Ninja400 the most. And the extra motor in the 400 made it easier to play with 600s in intermediate group.

 

Most of the track days I've attended have been Fridays before club races, so the advanced class is filled with racers, so while I trust them more than the intermediate riders, the closing speeds can be ridiculous. There is always a need to come off of your "staying out of the way" line and setup for a corner, and I feel that the closing speeds might be too much in some cases, even for the experts, when a lightweight bike moves onto the racing line.

I agree that the intermediate class riders are more to worry about, but I also think the speeds are much lower, just because they arent as likely to get the big bikes spun up as much. Just my 0.02.

The kink at the end of the front straight at Fontana (turn 1?) was my worst experience, because there's room for only 1 bike there, and you're pinned in 6th gear entering the kink on a lightweight bike.

 

Yeah, I don't think there is one right answer, rather it is a different set of risk factors.

 

IMO the 390’s are pretty cool but a little odd. A really mixed bag of kinda neat stuff and serious cost cutting. Smaller displacement bikes are often seen as stepping stones. Picked up a well built used one shouldn’t be too tricky.