2016 Cobra CX50 SR

Introduction

• The Cobra CX50 SR is a racing minicycle.
• It is high performance and requires attention to maintenance.

Now you’ve done it. You’re looking at a high performance 50cc motocross weapon. Your life is about to change. No more Saturday mornings sipping coffee, enjoying a relaxing morning.  It’s time to roost! 

Riding with your kids, or just taking them riding, is a fun experience. Hitting the track or trials, seeing their eagerness to learn and their sense of accomplishment upon improving has been very satisfying.  Learning to competently ride, let alone race, is not for the weak. It takes gumption and grit to continually fail but charge back for more, all while learning lessons and improving.  The really cool part of the experience is seeing it permeate in other “real life” aspects of their life.  No more crying when getting hit with a soccer ball, “I’m a moto kid, is that all you got?”  Stepping up to the Cobra is a big decision. One that will place you in the direction of what you will be doing with your boy for the immediate future!

The Cobra SR provides an exceptional platform to experience all of the above.  With class leading suspension, and a powerful motor.  Cobra has improved some small components on their 2016 bikes that will lead to an improved ownership experience.  Better seals and adjustability will keep your wallet padded a tad bit longer, as well as minimize the time required to keep the bike performing properly.  No matter what brand 50 your child rides, Dad will become a mechanic, as all of the little bikes need tuning, adjustment and maintenance quite frequently to keep everything running properly and safely.  50cc race bikes will require more maintenance than any other bike you will ever own. This is not related to just the Cobra, as the KTM offering requires roughly the same amount of work.

Changes

• Lots of smart changes for 2016.

For 2016, the Original Cobra receives many refinements including an updated rear shock, improved fork, and several durability upgrades.  Cobra has several class-exclusive features like a fully adjustable cartridge fork, twin-spar frame, three-way adjustable rear shock, and 5Gx 3-shoe auto clutch.

Changes:

-New rear shock with improved high/low speed compression adjuster.

-All-new SKF fork seal & swiper for more supple fork action.

-Improved steering head seals keeps out dirt, mud, and even high pressure water.

-Improved clutch cover sealing.

-Black, hard anodized wheels.

As an owner of a 2015 Cobra, looking at the changes, there was not anything that jumped out that made upgrading to the ’16 a must do…other than the need for a fresh bike.  Both my boys love the look of the new black wheels.  My older boy was excited to try the fork updates claiming less stiction in initial travel.  For me, I’m excited about better seals and prepping a new bike with the knowledge gained from our ’15. Cobra's changes to the steering stem seal are very welcomed, as typically we re-lube the steering stem bearing at 25 hours, and have to replace it around 50.  All of the updates and changes on the ’16 SR lead to a more refined machine that add up to a better experience for both the rider and Dad.

Power

With no changes to the power plant for ’16 I didn’t expect much of a difference. Immediately upon starting the ’16 though, there was an audible difference.  The bike cracked to life, fairly crisp and clean for stock jetting.  Being that I’m the Dad and not the rider, relaying how the bike runs is a little different than the standard DBT test.  My 7 year old felt the bike was noticeably faster than his current ’15, remarking that it felt quicker than his ’15 ever did. Visually this appeared to be the case as well.  My 5 year old, who has a ’15 JR model, loved the “big” power the SR offered.  He went through a bout of blipping when he first got on the bike, but said it was just to “feel” the power!  

Analytically, the clutch engages about 7200RPM. From there the bike pulls hard, eventually flattening out around 15,000. Being that there is not another gear to grab, you will regularly see the rider pinned endlessly at max RPM.  The bike accelerates hard and comes on with a hit.  Inexperienced riders will struggle with controlling the hit and chop the throttle, thus creating the dreaded “blip.” It is designed to be fast and for experienced riders. Overall the power is great on the SR. It provides ample power for the size of the chassis to get over obstacles it’s meant to, but large enough to make a parent clench!

One of the best additions I’ve done to the Cobra is install a Works Connection hour meter with a tach.  The tach is INVALUABLE as it provides necessary information to what state the clutch is in. Knowing how the clutch is performing has helped me create a dialogue with my boys about how the bike is running that goes beyond “good” and “horrible.”  Monitoring the clutch provided information to make better decisions and to know when we went too long on one component or another.

The clutch engages around 7200rpm when working properly.  There are two issues that typically arise and will deviate the clutch performance, which can be seen on the tach.  If the spring stacks loose tension, the clutch will engage below 7200rpm as there is not adequate force to hold the shoes in until the desired rpm.  If the clutch is slipping, the RPM will rise above 7200 before engaging.  Monitoring the engagement can be done by standing over the bike, slowly bringing the RPM up to engagement. When the clutch engages, you’ll feel it and see it on the tach. 

There are three key maintenance items that need frequent care: to extend the life of the clutch, protect the motor, and keep it running properly. Changing the oil every couple of hours is a must do.  Not changing the oil leads to drastically less life out of the clutch shoes, baskets, spring washers and CFD.  Besides changing the oil, the CFD (Cobra Friction Drive) will need to be torqued often, at which time Contact/Carb Cleaner should be used thoroughly to spray out the clutch spring stacks.  The clutch shoes have small ports on each side that allow you to spray debris out of the stacks.  

The Cobra motor uses a friction drive system, dubbed the CFD, to protect the drive train (crank, transmission, clutch, chain), which is also claimed to improve tracking through choppy terrain.  The CFD needs to be checked for proper torque often to operate properly. If the CFD is slipping, the motor will lose the “hit” it typically has, as well as not protect the drive train. Torquing the CFD does require draining the oil and removing the side case.  You’ll need to change the oil anyway, and clean the clutch spring stacks as described above. Cobra recommends checking the CFD torque at 2 hours initially and extended out from there.  After about 8 hours on the motor I check the CFD every 4 hours, with it almost always needing to be tightened to bring it back to specs.  Draining the oil, removing the side case, cleaning the clutch stacks and torquing the CFD usually takes about 15 minutes, and is well worth it, providing peace of mind and a properly maintained machine.

All in all, the Cobra motor runs great and is easy to work on.  Although it takes time to check the CFD, it’s better than fixing broken internal parts of which I had to do on other brands of bikes at a much higher rate.

Suspension

Truth be told the suspension is the main reason we switched to Cobras. Cobra has put a lot of time into developing and refining their own CARD suspension components with great results. The ’16 models come with a 32mm CARD USD Cartridge Fork offering 210mm of travel. The CARD fork is tunable through compression, rebound and a bottoming adjustment. Out back the bike is spec’d with a CARD rear shock coming with Hi/Low speed compression and rebound dampening adjusters. The ’16 shock has a more user-friendly hi/low speed adjuster compared to the ’15, with both adjuster screws being Allens instead of the high speed being a large nut.  

The bike is well balanced right out of the crate and easily tunable. Changes often yielded a visual difference, as well as the rider being able to notice the bike working differently, which can be difficult for riders of this age. From our experience the suspension is the biggest competitive advantage of the SR.

Chassis - Handling

• Parents have to set the bike up by watching the young rider.
• The Cobra is a turning machine but still has stability.

Proper ergonomics are so critical to being able to build skills from.  The seat/peg/bar height are all proportioned as they would be on a big bike, and provide a good platform to get started on. The limiting ergonomic factor is by far the stock bar bend, which is an odd bend with a lot of sweep. The stock bend puts most kids in an odd position on the seat, tucks the elbows in and down, not allowing them to move as forward as they should unless they are really good and really aware of what’s happening. Changing to a straighter bend bar enabled the rider to be in a more comfortable and powerful position on the bike, allowing them to easily get forward on the seat, and keep the elbows up.   There are two bar mount positions to accommodate a growing rider. I installed a 1 1/8” bar mount and 10* Mini Low Flexx Handlebars that drastically improved the ergos and absorbed the high frequency abuse.  

The SR pegs leave something to be desired width wise. Gunnar commented often that his feet hurt when riding at tracks where he bottomed frequently.  Cobra offers a wider peg as do several aftermarket companies that solve this problem.

From a parents perspective, my main priority chassis wise is for the bike to not do anything funny, or surprising, i.e. kicking off a jump, headshake, swapping, etc. Given the suspension needs to be set up correctly, with the stock set up most riders should be in the ball park. So with that said, we’re happy with the SR chassis. It’s a turning machine, but is still stable down the straights. Both boys noticed how easy the bike was to turn in ruts, flat tracking or railing berms. For fast or sandy tracks I always drop the forks in the clamps as with the small wheels it’s really easy to tuck the front end.

The Formula brakes work well, with great lever/pedal feel, until they don’t! Although they are easy to rebuild, they are difficult to bleed, a problem I’ve never had on any other machine, including other Formula models.  Speaking with other Father’s resulted in a lot of similar frustration. Figure the brakes will work great for 65-75 hard moto hours, so if you’re just trail riding you’ll probably get more.   

Conclusion

• The Cobra is a serious race bike.
• Not for beginners.

The Cobra SR. is very aggressive for juniors first bike, although there are some options to make it more rideable if need be. This is a true race bike, and demands to be treated as such from the rider and the mechanic. Although the main priority for this machine is motocross, we’ve ridden quite a bit off-road on the SR, which worked well on a variety of very tight and challenging terrain, never faltering or doing anything out of the norm.

For motocross the SR is a great choice, it does everything well and provides a great base for kids to build a serious skill set from. There’s not much to choose from in this cc range, but Cobra continues to refine their machines year after year, justifying the cost of a fresh bike if your rider is going to put a lot of time on it.