Front end washout: Riding technique or front tire to blame?

I bought a 2009 KX450 last December and have about 20 hours of riding on it. I've had a few instances where the front end washed out on me, most seriously about a month ago which resulted in a separated shoulder. The bike came with a Dunlop MX51 (Intermediate terrain) on the rear and a Motoz Terrapactor (Soft Terrain) on the front. Both are like new but I've read mixed reviews on the Motoz tire since it has directional tread.

 

The first time I was riding trails and wheelied up a long hill with whoops. When I brought the front wheel down it landed on a dry root crossing the trail at an angle and the front end slid out, I safely rolled off.

 

The second time I was riding the track at VDR and it seemed I couldn't push my speed in tighter turns without the front end wanting to wash out. I stayed up but was pretty wiped from wrestling the bike around those turns.

 

The last time I was going around a slower turn at Watkins and before I knew it, the front end must have caught a rut or washed out and I high-sided. I landed on my shoulder and separated it. Before I get back to riding I want to figure out what the deal is.

 

My suspension is sprung and valved correctly for my weight and the clickers are set very close to stock settings. I run both tires at 13psi.

 

As far as technique, I'm a pretty low-time MX rider but have years of trail riding under my belt. On the track, turning is probably my weakness. I've watched a few Semics videos and know to lean back when braking into the turn, then get my nuts up by the tank and my leg out when turning and accelerating out. I tend to lean forward when accelerating out of turns too. It seems I'm either fishtailing out or having to back off as the front end wants to slide out.

 

Any suggestions on how I can get my skill/confidence up to ride MX with confidence again? Is it the tire or tire pressure to blame? Having a separated shoulder is NOT fun and I miss the hell out of riding. Thanks!

Edited by jermag24

What is your sag set at? A little less sag (more preload) could help. Also try sliding the fork legs up in the tubes a bit. A little bit less air in the front tire could help. If your bike is pushing rather than washing out a narrower rear tire, or more air in the rear could also help. Finally, I have never run a Motoz tire but I would guess they are not the best front tire.

CoKTM

Edited by coktm

What is your sag set at? A little less sag (more preload) could help. Also try sliding the fork legs up in the tubes a bit. A little bit less air in the front tire could help. If you bike is pushing rather than washing out a narrower rear tire, or more air in the rear could also help. Finally, I have never run a Motoz tire but I would guess they are not the best front tire.

CoKTM

 

Thanks for the reply. My sag is set at 4" (about 102mm). My forks are at 10mm (second line). The front tire is a 80/100-21 and is set at about 13 psi. I read online that people were running as low as 7-9 psi in the Motoz tires because the sidewalls are so stiff. While I see alot of good reviews for the Terrapactor, there's also alot of hype. I could spend hours reading threads about what front tire to use but I'm smart enough to know 90% of the posts are uninformed opinions :)

On my 12 KX 250f I had real similar problems to fix it I adjusted my sag as it didn't have enough preload on and also raised the forks in the triple and got rid if that horrible Dunlop mx51 and went with Bridgestone m404/403 and it feels pretty good now

On my 12 KX 250f I had real similar problems to fix it I adjusted my sag as it didn't have enough preload on and also raised the forks in the triple and got rid if that horrible Dunlop mx51 and went with Bridgestone m404/403 and it feels pretty good now

So does increasing sag increase preload?

 

BTW, I spent 2 hours reading posts and site reviews about a bunch of tires and it doesn't solve anything. You say the MX51 is horrible, the next poster says it's the best tire he's ever used, you know? Anyway, my front tire is a Motoz Terrapactor, not a MX51. Thanks for the reply.

So does increasing sag increase preload?

BTW, I spent 2 hours reading posts and site reviews about a bunch of tires and it doesn't solve anything. You say the MX51 is horrible, the next poster says it's the best tire he's ever used, you know? Anyway, my front tire is a Motoz Terrapactor, not a MX51. Thanks for the reply.

mx51. In the rear isn't bad at all but not up front! Along with motoZ tires!! Ill never, ever run one again!!

So does increasing sag increase preload?

 

BTW, I spent 2 hours reading posts and site reviews about a bunch of tires and it doesn't solve anything. You say the MX51 is horrible, the next poster says it's the best tire he's ever used, you know? Anyway, my front tire is a Motoz Terrapactor, not a MX51. Thanks for the reply.

 

Increasing sag lowers front end ( think chopper) and decreases weight/bias to the front, making it harder to steer usually. Increasing preload ( screw down ring on rear shock) effectively raises the rear and puts more bias onto the front.

 

Joe

mx51. In the rear isn't bad at all but not up front! Along with motoZ tires!! Ill never, ever run one again!!

 

Can you expand on why you say MX51 and Motoz are crap in the front? No offense, but posts like these give zero useful information for people reading it. Have you run a Motox front? In what conditions?

Increasing sag lowers front end ( think chopper) and decreases weight/bias to the front, making it harder to steer usually. Increasing preload ( screw down ring on rear shock) effectively raises the rear and puts more bias onto the front.

 

Joe

 

Great analogy Joe, makes sense. I'll remeasure my sag this weekend with full gear and carefully measure it. Maybe I can reduce the sag 5mm or so to get the rear up a bit. I know when I stand next to the bike and push down on the pegs with my foot the back dips quicker than the front. I've read that they should dip together to tell you the suspension is balanced.

So does increasing sag increase preload?

BTW, I spent 2 hours reading posts and site reviews about a bunch of tires and it doesn't solve anything. You say the MX51 is horrible, the next poster says it's the best tire he's ever used, you know? Anyway, my front tire is a Motoz Terrapactor, not a MX51. Thanks for the reply.

The lower the sag the more the preload.

And yes I understand about opinions on tires and I had the mx51

The lower the sag the more the preload.

And yes I understand about opinions on tires and I had the mx51

 

What was your experience with the MX51? Did it tend to wash out?

I'm pretty sure you need to give it more gas.

Edited by pizzaforbreakfast

What was your experience with the MX51? Did it tend to wash out?

 

My experience with MX51's on two different bikes has been that they work great and most certainly do not wash out. 89 250 2 stroke and a '13 RMZ250.

 

Any time someone says a (well known manufacturer) tire is crap or tries to blame the tires for crashing, it pretty well wrecks their credibility. They are either causing it by their riding technique, using a tire in terrain it's not meant for, or are using a ragged worn out old tire (bad maintenance).

 

The only time I've been able to blame tires was using dual sport highway tires (BS Trailwings) on a slightly muddy MX track. It was fun, but that really wasn't what the tires were meant for.

 

Having never heard of MotoZ, it might be some chinese or fly-by-night venture not concerned about quality or R&D. Anything from Michelin, Dunlop, etc will work better than most riders will give credit.

If all of your suspension is set right and it sounds like you have the right riding technique all that is left is the tire my favorite is the Bridgestone m603

Check sag.  After that make sure your riding technique is good ie more weight on front end and start adjusting clickers after that.  Keep in mind that kawasakis front ends like to  wash out ie.  villopoto is great at demonstrating that.

I bought an '06 KX250F that had the same problem.  I noticed that the fork tubes were being pushed up in the clamps even though the pinch bolts were tight. After the front end let loose in a third gear corner and I got hurt, I pulled the front end apart and found that the triple clamps had been machined improperly where they grasped the tubes.  There were chatter marks on the clamping surface and it was only touching the tube on maybe 30% of the clamp.  So, I lapped (yes, lapping compound) the fork tubes to the clamps.  I had to pull them apart a couple times after doing it to clean off the lapping compound that came to the surface but after that they worked great.

 

My curent KTM had a similar problem only this time it was the forks constantly twisting in the clamps where my handbars would always end up being crooked.  The machining was ok but I noticed the metal was very shiny right where the clamping slit is.  Maybe caused by overtightening but the metal here was protruding and again not allowing the clamps to grip the tubes.  I simply filed the slit area with a file and that cured it. 

What was your experience with the MX51? Did it tend to wash out?

Hopefully I won't "ruin all my credibility" criticizing a large company here like Dunlop but I've personally had MX51's on three bikes an 07 RM 250 a 12 CRF 450 and a 12 KX 250f all front and rear. When the first came out I was like oh I better try the hot new stuff so I bought them for my RM at the same time my brother in law bout a set for his 09 KTM 300 on all the bikes I have rode with a MX51 front unless the conditions are very good the front end likes to wash out if pushed very hard for example if it starts getting wet and slick or their are a lot of roots and rocks maybe on a well prepped track it would be an ok tire but for offload riding I can't stand them the rear is ok it's only the front I don't like even running super low pressure to super high pressure it always feels to me like I am about to loose the front if I try pushing it very hard so sorry about a huge run on sentence and no punctuation I am on my phone and just don't feel like fixing it at the moment but anyways I hate the stupid debates about one thing being better than the other and everyone else is dumb if the don't agree with your opinion and its a big company it has to be good so if this is going to be a tire debate I'm out

No mention made of your weight

No mention made of your suspension settings

No mention made of your riding style.

No mention of the actual riding areas you go to.

 

Remember, until you get the suspension BALANCED front to rear, nothing else you change will really matter.

Fork height, rear linkage length, spring rate, front AND REAR sag, and finally suspension damping and settings, are all part of the equation. 

 

 

A stock KX requires lots of rider input to corner: you MUST put all your weight on the outside peg when turning and use throttle, not the front wheel, to turn.

The chassis geometry does not have a lot of oversteer (KTM, Suzuki), and is not balanced stock for low throttle level turning (Honda, Beta), but requires commitment in every corner.

I put 22mm triple clamps on my KX to get it to turn with less concentration.

 

An MX 51 is a 'non-transitional' tire: it works very good on perfect dirt, and very bad on compound dirt (silt plus rocks, mud plus blue groove, etc.).

It requires more throttle and more traction to work well.

 

The MX 71 works better on most CA dirt, accept track most track dirt.

 

I have found that on my KX, X, SX, and R, that the Bridgestone M403 90/100 is the BEST front tire period.

 

Try riding standing up and pulsing your front break lever enough to momentarily drop the front end. If it causes you to drastically change the muscles you are using to keep control, your front end is way to soft, and will always push out.

Have you checked your linkage bearings? I have had the same front end washing problem on two of my pre-owned Hondas. I have a couple of buddies that had the same issue on different bikes with linkage. In my and  my buddies experience, if your linkage is not maintained properly this will cause front end issues. From my experience, it takes just one semi-dry bearing to cause the bike to not settle/balance properly. If your linkage is not smooth, you can play with your sag, move forks up and down in the triple clamps, and change front tires until your blue in the face and you will still not solve the issue. Unfortunately been there done that. If bearings are dry or close to dry, I would replace them. If this is your situation and you end up changing the bearings, I bet your problem will be solved.

....

Edited by cdc351jeferson

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