GOING FROM A 4-STROKE 50 TO A 2-STROKE 50 OR 65.

For a kid's first dirt bike, there's nothing better than that little 4-Stroke 50cc for them to learn on. Before you know it, they're jumping it, shifting gears and riding the wheels off the thing.

When they outgrow that little CRF 50 though, you've got a decision to make. Do you get them a KTM 50 2-Stroke dirt bike with some suspension or do you bump them up to a KX 65 and forgo 50's all together? Well, I've done both, and here's what I learned.... 

2002 KTM 50 Pro Senior LC

​THE KTM 50 SX

There have been several names for these little bikes over the years. The KTM 50 Pro Senior, the Pro Senior LC, the 50 SX, the 50 SX Pro Senior, and on and on. Whether named by the Factory or made up by the Dads of the 50cc racing circuit, you'll find them called many things. 

Ultimately, if your kid is coming off of the CRF 50 or similar, one of your options is a version of the KTM 50. These are great little dirt bikes with a good suspension system and a powerful little motor. They're hands down superior to any 4-Stroke 50 dirt bike on the market when it comes to performance. These little bikes do need constant attention though. With high performance comes more maintenance. Expect to spend some time wrenching on these little bikes. And I'm not talking about just upgrading parts. I'm talking about replacing worn parts on a regular basis. These little motors put out some serious power for little riders, but all those high RPMS take a toll on engine and drive components. 

This little bike is designed for racing! So if your little speedster is ready to go from their clunky, no suspension, heavy 4-Stroke 50 to a serious motocross machine, then this is your bike! This is the next step in getting your kid on a true  motocross race bike and giving them the chance to be competitive in their class!

Sometimes seen as a draw back in the transmission department, these bikes don't have gears. So all that shifting they learned with their 4-Stroke 50, yeah that's out the window. Now they've got just one long gear. Gas and go baby! And boy do these things go!

​​​THE KAWASAKI KX 65

Now, why would I suggest going from a 4-Stroke 50cc dirt bike to a 2-Stroke 65cc? Well, the Kawasaki KX 65 has had only minor changes in the past 10 plus years. Grab a service manual for a 2000 and newer KX 65 and you'll see that it applies to models between 2000-2017! You may see that as a flaw, but on the other hand, there's been no need to change it. They have a proven machine that lasts and is competitive in the class. The only draw back to this bike is the suspension. Kawasaki could definitely benefit from putting some R&D into the suspension on these bikes, as they still use a traditional fork. Especially with the anticipated release of Yamaha's 65cc 2-Stroke in 2018 and KTM's already superior 65cc SX model. There's a reason I'm not mentioning the KTM 65 SX and the reason is cost. I'll explain more at the end.

So, since your kiddo has been ripping it up on their CRF 50, you may be thinking of bumping them up to a KX 65 (or other 65). Here are some things to consider: 

• ARE THEY GOING TO RACE?
• ARE THEY TALL ENOUGH TO TOUCH THE GROUND WHILE ON THE BIKE?
• DO YOU NEED TO LIMIT THEIR THROTTLE?

​
If your kid is going to be racing and they're coming off a 4-Stroke 50cc, I would recommend going with the KTM 50 SX (or similar) as long as their age and weight are appropriate for it. That will get your kid used to a 2-Stroke power plant that has a significant hit when the power band kicks in. I would not recommend going straight to a 65cc bike and putting them behind the starting gate immediately.

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IF THEY AREN'T RACING OR WON'T BE FOR A WHILE....

So your child won't be racing their new bike. At least, not right now. You are debating on whether or not to get them a KX 65 or a KTM 50, but they both cost about the same used. In fact, you'll find that in most cases, the KTM costs more. Plus, if you buy them a 50cc now, you'll probably end up bumping them to a 65cc sooner than later. After all, they've already been on a 50 for a while right? So why not just get it now?

If your child is riding well on their 4-Stroke 50, then they could be ready for a 65cc. You are going to have to spend some time teaching them how to use the clutch and constantly emphasize that throttle control is EVERYTHING when learning to ride their new dirt bike. This bike is big enough and powerful enough for most adults to jump on the back of the bike and teach the kid the controls and how powerful the bike is before you just send them off on their own. 

Most parents are concerned about the power of the 65cc and how their kid will transition. One thing you can do is put a governor screw in the throttle housing that allows you to limit the throttle. It's a simple drill and tap procedure to get the screw into the housing.

How To Put A Throttle Stop On A KX 65. ​

When screwed all the way in, the bike still has enough throttle to run just fine. As they build their skills, you can adjust it on the go. How it helps, is limiting how fast the power band of the bike hits. With the throttle limited, the bike is going to take a little longer for the rpm's to come up before it hits the power band. Your kid will recognize the rpm's climbing (because you taught them when you rode on the back and showed them the controls) and get familiar with how the bike accelerates. Without a governor screw installed, if they crack the throttle, these 65's go from zero to SCREAMIN' pretty quick. 

The 65's will sit a bit higher than the KTM 50, and if your kid has trouble touching the ground, you can do one or multiple things:

1. Purchase and install a lowering link. 
2. Shave the seat foam.
3. Raise the forks.
4. Expand the rear shock spring.

Raising the forks or expanding the rear shock spring will help the bike sit lower, but once your kid starts getting the hang of the bike, make sure you set the suspension appropriately. 


​CONCLUSION

• If your kid is going to be racing, then I would recommend the KTM 50's as the next dirt bike for a little rider coming off of a 4-Stroke 50.

 

• If your kid is not going to be racing right away, they're a weekend or recreational rider and your looking to keep costs low, then the 65cc is a good way to go. Just make sure your confident in your child's ability and teach them how to ride their new bike. TAKE IT SLOW!

To each their own, and although I have my recommendations, they are just recommendations. Always do what you think is right for your child and your situation and above all, HAVE FUN!!


Why didn't I mention the KTM 65 SX? 

The KTM 65 SX is an AWESOME motocross race bike! Can't beat it. The subject here though is a kid coming off of a 4-Stroke 50cc. The KTM 65 SX is a race machine and if your kid is racing, the natural progression is to go to a KTM 50cc race bike or similair. If your kid is going from a 4-Stroke 50cc to a 65cc, it's most likely because they're not racing and you're trying to stay ahead of the curve money wise and not have to buy so many bikes as they progress and get older. 

The KTM 65 SX has a higher all around price tag than the Kawasaki KX 65 so it kind of defeats the purpose of what your trying to do if you're trying to keep costs low.