Canadian,

Four-strokes have certainly become more reliable since their rebirth at the turn of the Millennium. However, the reason for the panic is that there is no sure way to tell how hard a bike was ridden or how well it was maintained. Was the oil changed every couple of rides or every couple of years? How much dirt went through the engine from a dirty filter? Was this guy putting through the woods on single track trails or did he spend most of his time at the sand dunes revving his bike like Justin Barcia on two cans of Monster trying to impress coach Gibbs? The reason those questions are important is that the cost to rebuild a four-stroke, in the event that it does blow up, is astronomical when compared to a two-stroke. For those reasons you aren’t likely to shake the stigma of lost reliability when selling an old four-stroke.

What’s qualifies as old? Well, that depends upon so many things. For a full-factory race engine, five hours is old. A race bike from a support team might be 20 hours. I would say that a stock motocross bike is going to become questionable, reliability-wise, after 100 hours. Again, that all depends whether it’s being ridden by a novice who hasn’t found fourth gear yet or a young pro who likes to flirt with the rev limiter all day long. Motocross is harder on a bike than trail riding, obviously, so that is a consideration. Two strokes don’t go any longer without service intervals. In fact, I would suggest that you have to put a piston and ring in a two-stroke twice as often as you would on a four-stroke, but the cost is insignificant. And most folks with any common sense can do it themselves. Blow a four-stroke up and you better hope Hillary Clinton is planning on subsidizing bike rebuilds with government funds. Hope you can still get some good loonies for that four-banger of yours.

PING

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Hey David,

It's always a blast to read your texts on Fridays, even for a French Canadian like me.

I've always loved dirt bike racing. There is something about this sport that makes it to never go old or obsolete. This time, I'm flabbergasted by the supermini's performances at the MEC. I mean these kids can pretty much clear all the obstacles just like the Pros. First of all, that's impressive. But is it normal?  What kind of power to weight ratio can these have nowadays? Relative to their size/power (or power/weight ratio) are these faster than the 250?  Finally, how would superminis stack up on a real supercross track? 

Keep it safe. Have a good weekend.

PS. Please get your hands on an Alta Electric MX bike and tell us about it.

Yvan Pelchat

Canada

Yvan,

Every generation has a group of great mini riders and today’s crop is no exception. Tony Blazier posted a video on his Instagram this week with an 80cc battle at Carlsbad in 1987 between Buddy Antunez, Jimmy Gaddis, Jimmy Button, and Jeff Emig that was epic. The only difference between then and now is that events like the Monster Energy Cup gives these pre-pubescent throttle monkeys a place to showcase how talented they are. And because they get to race that event they also get to spend more time on a supercross track practicing for it; that’s something kids from 10 or 20 years ago didn’t get to do. It is impressive that these kids are sending huge jumps and exhibiting skills way beyond their years. Stilez Robertson, Carson Mumford, and the rest of the elite mini crew definitely prove that the future is bright for our sport. The bikes themselves are 105cc supermini bikes and they are damn fast. When you consider the weight of the rider and bike they probably aren’t far off of a 125.

The MEC track is pretty watered down though. Real supercross tracks don’t have the room before and between obstacles and that would make a huge difference for the little bikes. Jumping triples, getting through whoops, and clearing rhythm sections probably wouldn’t happen. The cool thing about watching these guys now is seeing how comfortable they are on a supercross track at this age. They can’t drive, shave, or date yet, but they are jumping 70’ triples and scrubbing jumps better than any other mini generation. The supercross class of 2020 is going to be good.

PING

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Hi Ping,

Could you help me remember and understand the implications of the 1986 production rule?  Perhaps it would be best explained as follows:

1985 – difference between Jeff Ward / David Bailey / etc. bike and production bike from showroom floor

2017 – difference between Eli Tomac / Ken Roczen / etc. bike and production bike from showroom floor

I would guess that today, there is less of a difference.  But I could be wrong and would like you to write about it.

Thanks!

Nathan E.

Nathan,

I don’t know all the specifics of the production rule but you could probably go to the AMA website and find them. The rule was designed to close the gap between the bikes the factory riders had and the ones that support riders or privateer riders used. It mandated that the frame, swingarm, and airbox couldn’t be altered from the way it came from the manufacturer. Guys still push the limit on some of these rules; There was an issue several years ago where some mechanics were “polishing” the frame so much it was thinning the material. They were doing it in strategic places to make the frame flex more.

The difference between a works bike in the 1980s and a production bike was huge. The frames were different, the swingarm was handmade, they had works suspension, tanks were hand crafted to lower center of gravity, and the engines were built by the manufacturers; it was, for all intents and purposes, a completely different bike. Flash forward to today and the gap is much smaller. Yes, a factory team’s bike is lighter, has works suspension, and has a custom engine package. But the real advantage of being on a good team is having the bike built and setup around the rider. They aren’t necessarily trying to squeeze more power out of the engine, but rather make it useable for each rider. Quality has a come a long way as well. It was pretty common to break wheels, hubs, spokes, and any number of other parts with frightening regularity a few decades ago. These days, unless there is a recall issue (like the KTM spokes last year), those problems are rare. If you ever get a chance to see one of those old factory Hondas in person, look closely. Those machines were works of art.

PING