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Rear tire hitting fender on landings? **PICTURE ADDED**

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This may be difficult to get an answer but I'm hoping...

My bike is a 2006 YZ 125. The suspension is revalved for a 150 lb rider for MX. I have just lowered the bike with a Yamalink lowering link and followed the instructions for adjusting the front forks up in the clamps, and adjusting the rear compression. I was able to get the sag properly set at 100mm. I have gained weight and am now 164 lbs naked.

Rode the bike at the MX track today for the first time and absolutely love the handling and ride quality offered by the link. It has allowed me to go much faster around the track, and thus, jump higher and farther. However, if I land flat, the rear tire contacts the rear fender. My questions are: is this normal? is it hitting because of the lowering link? is it hitting because I am heavier now? is it hitting because I am jumping higher? and finally, what can I do to remedy this situation? This never happened before.

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Edited by ibmxfpro
added picture

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Yes, it's because of the lowering link. The link lowers the back of the bike (puts the wheel closer to the fender), but the shock still has the same amount of travel. Thus, the tire now travels far enough to hit the fender.

This is why I prefer internal limiter spacers inside the shock.

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I think all makes will hit the fender when you use all the suspension and combine fender flex. I'm @ 150 lbs and on an 08 kx450f, even before I changed the factory springs both tires hit the fenders. Don't worry about it, that just means you are using the full stroke. That's what it's there for, use it.

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Yes, all bikes do hit the fender, but we're talking about the wheel trying to go THROUGH the fender, because if the lowering link. If the link were stock and the OP was asking about bottoming on the fender, I'd say 'don't worry about it'. But in this case, I'd certainly keep an eye on it.

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Yes, all bikes do hit the fender, but we're talking about the wheel trying to go THROUGH the fender, because if the lowering link. If the link were stock and the OP was asking about bottoming on the fender, I'd say 'don't worry about it'. But in this case, I'd certainly keep an eye on it.

First of all, he never said anything about the tire going through the fender or trying to go through the fender as you put it. If this is true he needs to state it that way and we would approach the correction a different way.

I don't have any experience with lowering links. So I ask you, what kind of a fix is, as you put it, keep an eye on it? If the lowering link truly creates enough of a change that now when the shock reaches the end of it's travel the rear tire is theoretically or actually above the rear fender how do you propose he fixes it? By limiting the travel in the shock? By how much and how do you or does he do it?

I would think that who ever did the r and d on the lowering links would be

able to give you a more complete fix or understanding of what needs to happen if anything when you install the lowering link. Better than just keep an eye on it. I wish I could be of more help.

Is the rear tire just scuffing the under side of the fender or is it putting those tell tail white stress marks anywhere on the fender?

That would tell the tail of whether or not something drastic needs to be done.

Edited by kx450f63
additional thoughts

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i see 2 types of marks on fenders, a decent black mark and it shows full travel is used, and another, black marks all the way round the fender, this is bad and shows a problem.

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Just to clarify, the tire seems to be "scuffing" the fender and leaving small black marks. No white stress marks as of yet. This is only happening when I land with both wheels at the same time, ie flat landing (not casing). The guy I was riding with said it just shows I am using all of the suspension which he said was good. He looked at my front forks and saw the dirt line on the bottom of the tubes and said I was using all of the front as well. He said I could adjust the low speed compression a little firmer if need be but not to worry about it.

I just wanted to make sure that I was not putting myself in harms way by allowing this bottoming out to continue. If there is a way to adjust my clickers or preload that would keep the suspension from bottoming, I am all ears. Please detail your answers if you recommend adjustments so I will know what to expect from the adjustment. Thanks guys.

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A small amount of scuffing is acceptable. Flat landing is some of the hardest hits you can take because of the direction and amount of force being applied. Of course landing on an incline is even worse. You mentioned casing it, if you think about what happens when you case it, this means the center of the motorcycle touches or impacts before the suspension can completely do its job. That is why casing it feels so much more violent than just bottoming the pogo sticks, there is nothing in the frame to absorb this kind of impact.

As far as bottoming the suspension goes, it is ok to use it all up. You need to judge how hard it is bottoming. If you are feeling it just kiss the bottom of the stroke that is ok. If the velocity is too high at the bottom of the stroke this will feel harsh and potentially damage parts. Basically if you are feeling a sudden stop of dampening (harsh bottoming) you need to do something. Such as two clicks at a time on the compression dampening screw until the harshness goes away, or revalve, and or different springs. If it is just a soft kiss at the bottom of the stroke you are in business. Let'er Rip!

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It doesn't feel harsh. It is more the sound of tire hitting fender that alerted me to it happening. And the front isn't harsh at all. The bike is actually performing the best it ever has and making me feel like I went from zero-to-hero! Do you think my weight gain has affected anything? I will be back down to 150-155 by summer so I won't be revalving again.

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i think it sounds almost perfect, i would not worry.

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You can actually hear the fender hitting the tire? (or vise versa) That alarms me. If you could show us pictures of the fender that would be great. As long as you are not destroying the fender and you like the way it feels, that is all that matters. Gaining or loosing 5 or 10 pounds to an average rider is not that big of a deal.

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Check the 1st post...I snapped a photo of the marks left by the tire on the underside of the rear fender.

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Yes, it's because of the lowering link. The link lowers the back of the bike (puts the wheel closer to the fender), but the shock still has the same amount of travel. Thus, the tire now travels far enough to hit the fender.

This is why I prefer internal limiter spacers inside the shock.

After seeing the picture I now agree with MX TECH. If you are hearing the tire it the fender and by the way the rubber looks under the fender I think something needs to be done. Those scuffs are a little more extreme than normal. On the other hand if it does not get any worse than that I may say leave it alone if you are happy with the way it is handling. Talk to MX TECH and see what it takes to solve your problem and keep it handling the way you like.

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Hmmmm....I think I am going to leave the link in for awhile so I can get better at my turns and build more confidence. My plan was always for this link to be a temporary training aid for cornering and rut riding since I am to short to touch the ground at stock height. Once I feel comfortable enough with the necessary speed it takes to negotiate these obstacles in a smooth manner I am going to go back to stock height. In the meantime, can I make any adjustments on any of the clickers to reduce the likelyhood of bottoming ot the rear or do I just need to adjust the way I land off of jumps (i.e. land rear wheel first instead of flat)? Any help is appreciated and thanks for taking a look at my issue.

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a few more clicks of compression is all you need IMO.

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After seeing the picture I now agree with MX TECH. If you are hearing the tire it the fender and by the way the rubber looks under the fender I think something needs to be done. Those scuffs are a little more extreme than normal. On the other hand if it does not get any worse than that I may say leave it alone if you are happy with the way it is handling. Talk to MX TECH and see what it takes to solve your problem and keep it handling the way you like.

Thank you, KX. I'm glad you came to understand what I was saying. I advised him to "keep an eye on it", because #1 - he sounded committed to keeping the link, and #2 - if it's just scuffing the fender, no big deal. But like you wrote, if the fender starts breaking (white streaks in the plastic), that's a sign of a problem. And I guess #3 would be that it was not stated - and I don't know - how much the new link is supposed to lower the bike. If it lowers it 1/2", there's probably no cause for alarm. If it lowers the back 2", then I'd be nervous.

OP - add compression. You need to slow your suspension down so it doesn't go through the stroke so fast and bottom hard. If you get to a point where you've added compression and it gets harsh on things like braking bumps, but it's maybe still bottoming too much (for instance, on more than the biggest track obstacle), then you'd be a candidate for a revalve. The adjusters only control lo-speed movement - so I'm NOT suggesting that adding compression will keep you from bottoming, especially on obstacles that create high-speed movement - but at this point it can help. And if a revalve isn't in the cards for you right now, it's your only option.

:thumbsup:

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I've got a buddy with the 1.75 Yamalink, same issues. The link claims higher leverage on the shock, making the bike softer and plusher for the same settings. At your weight you essentially re-sprung your shock for your size, probably giving you better handling characteristics. My buddy on the other hand, weighs a little more than you and ended up going one or 2 spring sizes up from the MXTech recommendation for his weight. He also cranked in his high and low speed damping quite a bit as a result of the increased leverage. He still transfers a significant amount of rubber on to the underside of his fender! I think it is just a side effect of having more travel than room between your fender and tire. After watching his suspension, I don't think there is much there that will break and cause serious problems.

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