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Fill a library with the things I don't know about my bike ;) Any members from Alberta here???

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Hey guys!!

 

Just want to say thanks to everyone that's been replying to my posts and whatnot! Really happy I've got a newer bike but of course now I'm realizing how very much I don't know! Well, I already knew about the not knowing but still... :) So how exactly does rev limiter work? I'm told my 150rb has it- is it to save the engine from riders who don't know when to shift properly? Is that it's main function?

I haven't had any time really to get out on it much and what I want to do is get myself on some flat ground and figure that out first. I had fun at the track for the first time and did some teeny jumps on the two tabletops that they have in the back of the course but I totally played it safe! 

And what exactly is the procedure for coming down steep hills? I stupidly came up over a steep hill and promptly didn't know what the heck I was doing and flopped over- laugh it up- it was pathetic ;) it really sucks not having someone to be with me out there :( 

I'm headed to Calgary this upcoming week and I thought I might take it with me and try out the beginner track at Wildrose MX track. They're supposed to offer lessons on Wednesday nights but so far they've been horribly uncooperative so I thought I'd find some little kids on the beginner track to teach me the ropes :) it IS open to full size bikes too. I think I might be a tad bit embarrassed? I don't care about falling over or whatever but geez some people are just born good at everything, you know? Not afraid to tell you so either... Anyhow, if anyone has been out to Wildrose track in Calgary could you let me know??? THANKS AGAIN!!!!

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Rev limiter works by the ECU (electronic control unit) cutting the ignition in some form, at a preset rpm. That preset rpm on your 150R is up around 14K, so you're going to have to work at it to get to where it will kick in. And yes, it's there to keep the motor from revving to a point where destruction is a sure thing.

As for riding techniques, hit up YouTube. There are videos detailing just about every riding situation out there. Jumping, cornering, going uphill, going downhill, ruts, you name it and somebody has made a video about it. :thumbsup:

Edited by OLHILLBILLY
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Ut oh, you asked now I have to write up a dissertation. 

 

In a nutshell an engine can destroy itself if it exceeds a certain engine speed. There are two common forms of damage that can result from over speeding and engine.  The first is that the valve springs cannot move fast enough to keep the valves following the cam lobes.  This is called valve float.  When this happens the valve timing effectively is off.  This results in a valve that stays open as the piston comes to top dead center.  The piston strikes the valve and the motor destroys itself.  The other major rev related failure is due to the piston's speed.  At very high revs the piston is moving extremely fast in the bore.  At each end of the bore the piston must decelerate to a complete stop, change direction and accelerate back up to that enormous speed.  The higher you rev, the faster the piston speed and the higher the G force load on the piston, small end bearing and wrist pin.  You can reach a high enough engine speed where these loads cause a failure.  In the ones I've seen the piston breaks at the wrist pin hole but failure of the connecting rod or crank are also possible outcomes.

There are two ways you can over-speed an engine.  There is a throttle induced over-rev and a mechanical over-rev.  A throttle induced over-rev is just want it sounds like.  The rider applies too much throttle for the situation (gear selection, load and speed) causing the engine to exceed it's maximum designed engine speed.  This is what a rev limiter protects.  As OLHILLBILLY described. The ECU (the computer that controls the engine) stops firing the spark plug to bring the engine speed back down.  This happens very quickly (think 300 milliseconds).  Once the engine speed falls the ECU starts firing the ignition again.  Because it happens so quickly the rider most likely hasn't reacted yet and the engine speed climbs and again exceeds the value where the ECU cuts the ignition again.  This cycle continues in quick succession until the rider reacts and reduces their throttle input, changes gears or the terrain applies more load to the engine.  That cycle of the engine speed going up, the ignition cutting, the engine speed falling and the ignition firing again is that signature noise of a rev limiter BOP-BOP-BOP-BOP you hear.

As I mentioned there is another type of over-rev called a mechanical over-rev.  This occurs when an incorrect gear is chosen.  If the rider downshifts too far the momentum of bike forces the back wheel to turn which in turn forces the engine to spin.  If the gear chosen is low enough in relation to the bikes speed it can force the engine to spin faster than it's designed limit.  The rev-limiter will engage but it has no effect since the engine's excessive speed is not being caused by the engine itself but rather the bike's momentum.  Imagine going 100 miles per hour, pulling in the clutch, downshifting to first gear and letting the clutch out.  Luckily dirt bikes have a couple of inherent safety measures that are inate to their design and use that prevent this from being a common problem.  Dirt bikes are fairly light and are most often ridden in relatively low traction conditions.  Usually when one accidentally downshifts too many gears on a dirt bike in the dirt, the result is the rear wheel locking up due to excessive engine breaking instead of the engine being forced to spin past it's designed limit.  That's a general rule of thumb and not guaranteed so you want to avoid downshift mistakes at all costs.  On high traction surfaces with heavier vehicles, downshifting too far will almost certainly result in a mechanical over-rev that damages the engine.

Now you know more than you ever wanted to about a rev-limiter.

Doc

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OLHILLBILLY is right about the YouTube vids.  There are a lot of very good, helpful ones available.

I'm not sure if there are any that are local to you but joining a riding club can be a great way to improve and have fun.  Some, like the one I belong to, offer free lessons but even the ones that don't have set formal training sessions can be a great resource.  Watch some riders in certain sections of the track (even non-club tracks) and see what they do.  Also, go up to some of them in the pits to introduce yourself.  Most riders are very friendly (especially to new riders) and are happy to tell you about what they do in certain parts of the track and why and also what things they do that you shouldn't try to copy right away.  Some may even be willing to watch you ride certain parts of the track and provide feedback to you.  Try to work on one or two things each time so that you can practice them to proficiency and then move on to the next thing and that way you improve steadily without taking up a lot of time from the ad hoc instructors.

Other good advice that you will hear is to get out and ride.  Simply having more seat time makes you better -- especially if you intersperse some focused skill training with times of just general riding for fun.

Getting better can be a lifelong journey of fun so take it at whatever pace is good for you.

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Another thing I forgot to mention is local bike shops.  Some may have people who can suggest good local spots for various types of riding and some have bulletin boards where you can tack up a note asking for riding buddies.  If you go to a new area with trails, don't be shy about asking other riders to suggest good trails to start on for the area or asking if they mind if you try to follow them.  (Probably no one would mind but by asking, it might make them check every so often to see that you're doing okay or they might stop before trickier sections to alert you or to suggest a brief break before tackling that section.)

Wherever I've ridden in Canada and the US I've always found that dirt bikers are some of the nicest, friendliest, and most helpful people so don't be shy.

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New to riding too and don't know much about southern alberta other than some of the riding you guys have looks wicked in YouTube vids! I'm in the northeast near cold lake.

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New to riding too and don't know much about southern alberta other than some of the riding you guys have looks wicked in YouTube vids! I'm in the northeast near cold lake. And I don't know if I'm allowed to mention other forums or not, but snow and mud is a really good one for ab/bc/sk riders. There is more atv/snowmobile riders on there than bikes but there's still lots of people in the powersports world so I'm sure they could help you out with dealerships/shops/trail or track info that's local to you.

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New to riding too and don't know much about southern alberta other than some of the riding you guys have looks wicked in YouTube vids! I'm in the northeast near cold lake.

Thanks!!!

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