Keefer Kuestions 8-29-17
Kris Keefer

KEEF-ucious Say...



I need some help. It was like I woke up one day and my bike had lost all power. I find myself having to drop into first gear in corners far more than previously. There is just no bottom end. The bike just bogs. Also, no top end. Gears run out quick and I'm shifting way more. It feels "hollow." The power is just not there. I have the power tuner and my bike is set to stock mapping. My riding buddy also has a 15 YZ250F and I jumped on his to make sure I'm not crazy - nope I'm not crazy. His bike feels like a damn rocket ship compared to mine. I bought my bike with 45 hours on it so I'm fairly certain the top end has never been rebuilt. It now has 73 hours. I am trying to squeeze this riding season out of it before a rebuild. Am I asking too much time out of this motor? Could this loss of power be explained by a worn-out top end? Have you ever experienced something like this?

Thanks for everything you do Keefer,



Thank You Jonathan for the email... 


I can almost guarantee it sounds like there might be some dirt in your valves and or your top end (piston, rings, valves, valve seats, etc.) need to be changed. 73 hours is a lot of time on a 250F top end and you should feel lucky it has lasted you this long. You also should look into changing your clutch plates and look at your clutch basket for wear marks. Sometimes guys can't figure out why their bike is so slow feeling and it ends up being burnt clutch plates.


 In this case I would definitely take your top end off and put a fresh piston, rings, pin and clips in. While you're in there do a leak down test on your valves to see if it's time for a fresh valve train. Changing your air filter and engine oil religiously is key to a long lasting 250F engine! Let me know what you find! 






Hey keefer,

I'm getting a new bike soon and wanted your breakdown of the 350SX-F motor/power characteristics. I have narrowed my search down between the KTM or husky 250f or 350f.

I love 250f's and currently ride a '15 YZ250F. I recently bought a 17 CRF450R and I absolutely hated it for the simple fact that it was to fast for my liking. The power was so jerky and way to much bottom end/torque, which made me feel like I was constantly in danger of whisky throttle. I don't get that sensation on my 250F for obvious reasons which is why I like it so good. Super smooth off the bottom. I'm wondering how the 350 is as I don't mind a strong mid to top but despise the feel a 450 has initially with it trying to hop out of ruts or push in corners with just the slightest twist of the throttle. I hear the KTM250F is fast as well so I'm struggling with the decision.


I'm 5'10, 190lbs. Experience level is locally B and regionally C class. I race vet 25+ and 30+.


I really appreciate your response. I love all the content you put out and hold your opinion in high regard when it comes to bikes. Thanks again


Justin Barnes PT, DPT




Your question is a common one among riders who think the 450 has too much power. The KTM 350 SX-F is the perfect blend of just enough bottom end with tons of mid to top end for your liking. It will not get away from you in corners like a 450 can and gives you just a little more bottom end than a 250 (to get you over any obstacles (easier) that are immediately out of corners). Every time I ride a 350 I always wonder why I do not ride one more often, they are that much fun. The 350's power delivery is snappy and exciting, but not arm jerking like that 2017 Honda CRF450R can be. I wouldn't get a 250F for the simple fact that you're 190 pounds and it will be a lot of work to get around the track in a quick manner. The 350 weighs as much as a 250F nowadays so weight will not be an issue. Hope this helps! 






Kris, I have always enjoyed you on the Pulp Show and now listen to all of your Podcasts.


I have 2 questions.


1- I am 59 and ride a Kawasaki 2009 KX450F adapted to a Recluse clutch since I blew my left hand apart in a crash at Thunder Valley and got 6 titanium knuckles 4 years ago. 

I have never felt that the front brake works very well. 

I have had 2 dealers "bleed the brakes and adjust and do various things" and I still feel that it is not very responsive. 

1 finger braking (pulling up to my van) hardly slows the bike. On the track, multiple fingers do the job but not like I expect. 


Any thoughts on the front brake response?


Can a better master cylinder be installed or would better cables matter. I have ASV foldable levers. 


I have owned the bike since new and don't expect to ever buy a new bike "at my age". 

I still ride MX weekly and race some of the RMXA events here in Colorado. I am "slow as F**k" but have a total blast. I jump much better than I take corners. HAHA


This front brake response has always bothered me. 



2- Do your t-shirts run small or large or pretty spot on for size. 

I am an XL in smallish shirts and a L in large running shirts. 


I am planning to order a couple.


Thanks a lot.


I totally enjoyed the "suspension clickers" podcast and also the "must have" podcast. 


Have a wonderful week. -Bob



Hey Bob, 


The 2009 KX450F was known for weak brakes and I understand what you're going through. Ride Engineering has a brake caliper that will increase your stopping power and although not super firm (or touchy) at the lever, will help you stop quicker. The lever pressure is linear and you will get more out of pulling the front lever in compared to a stock set up. The offer complete kits, but I would recommend just the caliper as this would help you. 

If you normally are a large shirt I would get an XL in our shirts. Thank you for the message and look forward to hearing how you like the brake caliper. 








Hey Keefer, Love you on the Pulp show. I just bought a 2015 Husky FE501S. Have you ever tried a K&N air filter on any of your bikes? How about the Maxima ready to use ones? I'm looking for something that will protect the bike but is easy to keep clean. I hate cleaning traditional foam filters.

Thanks Matt




I haven't used K&N filters on my motocross bikes because I haven't had the opportunity yet.  We have ran them on some off-road bikes when I was at DR, but they ended up getting dirty and clogged fairly quickly. Washing them was easy, but the performance of the filter wasn't any more notable than a standard foam filter.  


The Maxima filters are just fine and I have used those in many test bikes here at Keefer Inc. I have used No Toil and didn't like the quality as it let some dirt in my airbox.  

Stick with Maxima filters or buy a few Twin Air's and get them all prepped up so you don't have to clean air filters as much. I hate cleaning air filters as well, but prepping a few at time can really help you when you need to swap out one in a pinch. 







First off, the website looks great, excellent job with the design. I had a question about the Alta bike. Some background, I have a bachelors and am working in my masters degree in mechanical engineering, so I have a pretty in depth understanding of how these things work. Anyway, I was curious if the Alta bike has regenerative braking like most electric cars such as the Tesla. When you cut off the throttle, is there strong "engine breaking" on the bike? And if so, how does the impact the gyro effect in the air? If you don't apply some throttle is it like tapping the rear brake on any other bike?


Blake Betsill




I couldn't give you that answer directly, but I do know the engine braking IS adjustable on the Redshift. When I was testing them earlier in the year, the engineers at Alta were able to adjust engine braking for me accordingly. However, I think the engine braking is preset for production. The owner will not be able to adjust the engine braking when they purchase their new unit.

As far as braking in air, I can tap the rear brake at any time and it does the same affect it does on a gas powered m/c. All feels similar! It does nothing out of the ordinary compared to your bike at home. 







I don't wanna buy a new motocross bike since I will only ride it a few times per year, so I going used.

I found a 2006 Honda CR450f (asking $2900) and a 2016 KX450f (asking $5500). Both are very clean, in fact the KX has never been ridden and the CR is very low hours, like not even a back tire worth. Both owned by an older vet rider.

I lean towards the Honda because it's cheaper but the KX is 10 years newer, maybe more advanced in technology so I assume it would be a way better ride?

Let me know your thoughts.

I'm a younger vet B rider that doesn't race, just going to a few practice tracks per year to rail some ruts and bust some doubles!


Thanks, David.





Go with the Honda! The 2006 bike was a great bike that had a great chassis and engine plus it was easy to go fast on. The re-sale of the Honda will be good as well. The Kawasaki has an air fork that you don't want to screw with for only riding a few times per year and saving some money going wth the Honda will feel good on your wallet. Put the money (that you will save buying the Honda) and let it go towards some extra parts for the red machine. Yes, the green bike has FI, but if the Honda is new like they say it is, you'll be just fine and have a smile on your face.





Hey Keefer, been following and been listening to all the new stuff and Pulp stuff, as always, complete awesomeness! I had a question about maintenance & care on all the new bikes. I scooped up a '17 YZ 250F earlier this year, an upgrade from my previous '08 Kawi 250f. With all the new EFI and jazz that I am still getting used to, I wanted to know your thoughts on care and maintenance on these new era bikes, in general, and now that they have all these electronics on them and such? I am a local C-class rider, racing a few times a year and just for fun riding a handful more, but looking to start racing more. I have about 11 hours on the new bike so far this season and have only been doing oil changes after every ride and cleaning/changing the air filter after every ride and keeping it super clean.

I had that '08 Kawi and other than routinely changing the oil and air filter after every ride, and a new top end every season I was golden with it. Just keep up the same old with the new bike, or is there something else special that I should be doing with regular maintenance on these new bikes?

I appreciate the help man, thanks! -Nick




It sounds like you're doing exactly what you're supposed to do. Nothing out of the ordinary with these bikes, besides routine air filter and oil/filter changes. Keep an eye out on your spark plug cap as sometimes on these models they pop up slightly and you will get a dirty/sputter on acceleration. You can purchase a spark plug cap holder over at

The bike you have is reliable and will last you a long time if you take care of it like you are... Enjoy! 





Hi Kris,

My name is James and I have just moved to Southern California from Ireland at 22 to follow my passion of riding dirt bikes. My goal is to do my best in the sport with my racing and also have a career in the motocross industry here.
I have a lot of talent riding and I ride a 250f really well. Bike testing is something that I'm really
Interested in, especially 250f testing.
I have an excellent feel for the little things when I'm riding. Sometimes it's a downfall for me in my racing.
I just wanted to ask you about how to get into bike testing or id love to help you out anyway I can to learn.
I know you get these emails or messages a lot from people but I'm different. I've already moved across the world with nothing to achieve this dream. I just need some advice/help with the next few steps. -James 


Hey James, 


Thanks for reaching out and wow that is a big life changing move you just did! I hope everything works out for you because that takes some balls to do.  

I am good on test riders right now, but I will keep your name in the hat just in case something comes up. You never know! I like riders like yourself that shoot me emails from time to time to see if I need any help. I will be completely honest with you though, 

it is tough to find someone that can ride well, write well, take instruction and get the work done in a timely manner. 

It seems easy, but you would be surprised on how many people just want to ride cool shit and get some Instabangers on their social media. From the outside it seems like I just ride dirt bikes and come home and hang out with my wife and kid. I wish it was that easy. You seem like you are doing it the right way by betting on yourself and following your passion. I applaud you for doing this. The thing I could suggest is keep tinkering and trying stuff on your own bike. Maybe have your friend change some clickers on your suspension (without you looking) and then go out and try to feel which way he went. That’s what I used to do before I got hired on at KTM back in the day. The more you know the better you will be at evaluating. Maybe I will see you at a local track soon and we can chat. Just keep working hard and good things will happen.







If you have any “Kuestions” for me you can reach me at kris [at] keeferinctesting [dot] com (kris [at] keeferinctesting [dot] com).