Tag Archives: Dear

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DEALING WITH ROCKS AND ROOTS: MR. KNOW-IT-ALL

Dear Mr. Know-It-All,
I purchased a used YZ250 after riding an ’04 XR250, and I primarily ride off-road. The area where I ride has lots of rocks and roots, and while my old XR was slow, it was extremely smooth on the trail. However, the YZ has a strong engine but the suspension feels off, as it doesn’t seem to handle the rocks well. I would appreciate any advice you can offer. I understand that the YZ is a motocross bike, but it’s really rough on me!
– Todd
via [email protected]

Todd, I want to inform you, without any harsh criticism, that the most important aspect to consider when riding in rocky terrain is the suspension. Serious riders in Colorado typically have their bikes set up with lighter springs and valve adjustments. If you’re using stock motocross suspension, riding on rocks, stones, roots, and harsh terrain will result in a rough ride. You can try adjusting the compression settings in the fork and shock to make them softer. Additionally, using softer springs would likely be beneficial. However, my wise suggestion is to consult with a professional suspension tuner who is knowledgeable about your riding area and the varying terrain conditions. They will take into account your height, weight, and riding ability to customize the suspension settings for optimal performance on the specific landscape.
One more thing to consider is the impact of tires and air pressure on the feel and traction of your bike. In Colorado, riders commonly use rear tires with a sticky compound and a foam insert for extra cushioning. They also either use a Tubliss front system, which allows for lower air pressure without the risk of pinch-flats, or a plush front bib mousse for added comfort and traction.

If you don’t mind showcasing your lack of knowledge to the world, we won’t deny you the opportunity. Send evidence of your failures to [email protected] or Mr. Know-It-All
Dirt Bike P.O. Box 957
Valencia, CA 91380-9057

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HOW FAST ARE THEY? MR. KNOW-IT-ALL

Dear Mr. Know-It-All,

What is the actual top speed of a modern 450 motocross bike? I’ve read on websites and YouTube comments claiming a KTM 450SXF is capable of 123 mph in stock form. I can’t see that being possible, as these bikes are geared to race on an MX or SX track, not drag raced. Could you please clarify?
Ken
via [email protected]

Well, Ken, while I don’t have the exact numbers, around the 120-mph mark is in the hunt for a top-speed run on a properly geared 450. The real issue comes with the gearing, setup and traction. About 10 years ago we were out with Robby Bell, who was testing his Precision Concepts KX450 for an upcoming Baja race. He and his mechanics had a radar gun and shot Robby, who was doing flat out in fifth-gear runs on a very long dirt road that had a slight rise going one of the directions. After a dozen runs, with each stint pushing the 103–104-mph mark, one of the tuners gave Robby a backpack full of rocks. His next run was 4 or 5 mph quicker both ways. I was informed that the rear tire was actually spinning rather than gripping at over 100 mph. The additional weight put more load on the rear tire, enhancing the grip, and therefore the top speed improved.

If you don’t mind displaying your ignorance for the world to see, who are we to deny the opportunity? Send evidence of your failures to [email protected] or Mr. Know-It-All
Dirt Bike P.O. Box 957
Valencia, CA 91380-9057

Click Here for more Mr. Know-It-All.

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KTM TPI STARTING RACKET: MR KNOW-IT-ALL

Dear Mr. Know-It-All,

I have a 2020 KTM 250XC-W TPI, and I’m concerned about a noise that it makes when I press the starter button. I have already replaced the clutch pack and the Bendix, but that hasn’t solved the issue. I’m wondering if the problem could be with the starter. Can you please help me?

Robert
via [email protected]

Noises from the starter system can be quite alarming, but they are more common in the 2008–2016 models and less so in the newer 2017 and later models. The clutch pack replacement you did is unrelated to the starter system, so it didn’t have any effect on the noise issue. Starter motors usually don’t make noise unless the bearings are failing. You can check the bearings by removing the Bendix and manually spinning the starter motor. If the bearings feel rough, it’s time to get a new motor. It’s worth noting that the motors have a notched feeling due to the internal magnets, so they don’t spin freely. The most likely causes of the noise are the Bendix and starter motor support bushings in the cases. Take a close look at them and replace any that have worn Teflon coating. Enjoy your rides, and thanks to Slavens Racing for providing the necessary information to address this question accurately.

Click Here for more Mr. Know-It-All.

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CHAIN BREAKER: MR KNOW-IT-ALL

Dear Mr. Know-It-All,

I recently experienced a broken chain when I was far away from my truck. Do you have any advice for this situation? It was a terrible experience because I didn’t have any tools to fix it, and no one in my group had a tow strap. My friend used his leg to push me, but there was a lot of sand. Now, I think my friend hates me! It took us hours to get back.

Stewart S

via [email protected]

I’m going to be completely honest with you, Stewart. The majority of chain problems are caused by the lack of maintenance and failure to replace worn-out parts. You should inspect your driveline after every ride to check for wear on the links, excessive stretching, and degradation of the masterlink. By inspecting the links, you can assess the condition of your chain. Worn plates indicate significant usage and the need for a new system. This includes replacing both the front and rear sprockets! Don’t take shortcuts, and one last piece of advice: Always carry a tow strap, a mini chain breaker (Motion Pro offers these), and a spare master link!

If you don’t mind showcasing your mistakes to the world, we won’t deny you the opportunity. Send evidence of your failures to [email protected] or Mr. Know-It-All

Dirt Bike P.O. Box 957

Valencia, CA 91380-9057

Motorsport

The Chevy Citation X-11: A Rare Gem from the 1980s

Let’s take a trip back to 1982 and explore the fascinating world of the Chevrolet Citation. Now, you might be wondering why we’re talking about a Chevy Citation, which was not exactly a beloved car. However, this particular model, the X-11, stands out from the rest.

The X-11 was the performance version of the Citation family, which primarily consisted of three-door and five-door hatchbacks. In its debut year of 1980, there was even a two-door coupe, but it didn’t last long due to lack of interest. However, the hatchback versions were incredibly popular, with over 800,000 units sold in the first year alone.

Despite its initial success, the Chevy Citation was not known for its long-term reliability, which explains why they are so rare to find today. Nevertheless, the X-11 model, with its sporty features and performance enhancements, has managed to maintain its appeal over the years.


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TPI CRANKCASE PRESSURE SENSOR ISSUES: MR KNOW IT ALL

Dear Mr. Know-It-All,

My 2023 KTM 300XC-W has about 120 hours on it and has been flawless … until yesterday. The bike was running as if it was fouling a plug. It would not clean out, like a bad case of laryngitis. I changed the plug, put fresh fuel in it and made sure my filter was spotless, and still no changes. What could be the culprit?

Alex B

via [email protected]

Alex, it’s a new-world order with these fuel-injected machines. The TPI KTMs have numerous sensors, and one of these is most likely your machine’s infection. I believe it’s the crankcase pressure sensor (has a black tube leading to the back of your cylinder), and over time the tube accumulates debris and carbon from within the cylinder. Once clogged, it provides a false reading to the machine’s brain, the ECU. I would remove this tube and the sensor itself, and clean it with a contact cleaner and compressed air. Once scoured, your machine should run crisp and clean. This process should be a periodic form of maintenance on the TPI machines.

CRAMPED
Dear Mr. Know-It-All,

I’m a Beta 500 dualsport rider and have trouble getting forward in the turns. I’m pretty flexible, but it feels like the bars are in my stomach, and my rear end is hanging off the rear fender. I’m 6-foot-4, 205 pounds in full dress.

Thanks for the feedback (if you actually answer this!)

Drew L.

If you don’t mind displaying your ignorance for the world to see, who are we to deny the opportunity? Send evidence of your failures to [email protected] or Mr. Know-It-All

Dirt Bike P.O. Box 957

Valencia, CA 91380-9057