Posts
2017
Joined
8/31/2010
Location
AU
Edited Date/Time
1/25/2012 7:10am
Hey guys need a little bit of expertise
Was riding my 2011 ktm 250 excf today through some high speed rough terrain, when I hit a wash out and heard a clunk like the suspension bottomed out. Now the front forks are really soft, as in you can almost push them the whole way down just by sitting on it and pushing the handlebars down. and they won't fully rebound. they sit around 1-2inch from fully uncompressed.
The only thing I've done with the suspension is harden it up via the clickers.
What could of caused this?
Was riding my 2011 ktm 250 excf today through some high speed rough terrain, when I hit a wash out and heard a clunk like the suspension bottomed out. Now the front forks are really soft, as in you can almost push them the whole way down just by sitting on it and pushing the handlebars down. and they won't fully rebound. they sit around 1-2inch from fully uncompressed.
The only thing I've done with the suspension is harden it up via the clickers.
What could of caused this?
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We bought my son a left over 2009 125 at the beginning of this year. He was not putting the air filter back on correctly and a bunch of dirt got down in with the piston. It wouldn't start the one day so I took it back to the dealer. He put a compression gauge on it and said it was real low.
I do not know enough to replace the piston m self so I had them do it to the tune of 500 bucks, Should this have been under the warranty or since it was us not putting the filter back on correctly, does that void it.
Thanks for any help and I would not have an issue going back to the dealer and asking them about the warranty coverage.
If you haven't ever had the forks off, you still need to check the pinch bolts and alignment. Loosen the triple clamp pinch bolts up and then re-torque them. Also, loosen the axle pinch bolts and the axle nut, take the bike off the stand and compress the front forks a few times to center the axle. Tighten the pinch bolt closest to the axle nut and torque to the axle. Loosen the 1 tightened pinch bolt and then torque the axle pinch bolts. The alignment of the front end can become tweaked over time from crashes or hard impacts.
If you do all this properly and the problem persists, you probably have a problem internally with the inner cartridge. In that case you will need to have the forks serviced.
How would binding forks make them feel ulta-soft as the OP describes?
The only thing you could really do is refute the labor charges on the service work. you could ask the service manager what the flat rate time is quoted by KTM to replace the top end. Like I said, probably no more than 2 hours service time. If they billed you for over 2 hours, you need to have the manager break-down the time spent and see how long it really took them. If they incured extra time due to problems on the bike, the price is legit. But, if the mechanic was just slow and took his time and spent 4 or 5 hours rebulding the top end, the bill should have been lower.
Just fome FYI for the next time you take a bike for service. Never agree to the price of a quote for a job. For example, if they quote you $500 for the top end, the service manager knows you are willing to spend $500 so they are going to make sure that bill comes in right around $500 to maximize what they can charge you. If you would have said im willing to put $700 in it, they would have found other stuff to replace and charged you extra time to charge a bill around $700. you can't blame them for not doing it, that's just how business works. Instead of agreeing to a quote in a dollar amount, tell them you want a quote in shop time on how long it's going to take for the repair. You have more leverage in this position because the shop knows they only should spend X amount of hours to complete the repair. If they run over time by a large amount and your bill is high, you will be in a better position to refute the original quote.
In this situation with the inner cartridge not returning to home position, the cartridge is already starting out inside its own stroke. Oil is displaced as the inner cartridge travels down throwing off the balance of the distribution of the oil. Alot of times cavitation occurs in these situations and the forks have to be serviced because the oil loses its viscosity. When the oil is not properly distributed into the inner cartridge, it will typically transfer into the outer cartridge. The oil in the outer cartridge controls the bottom 1/4 of fork travel. With more oil in the outer cartridge, the colume of air trapped in the outer cartridge is reduced and decreases the stiffness value of the air spring. All this adds up to a fork that easily blows through the first 3/4 travel and causes the fork to bottom easy. The valves aren't properly in tune and the fork spring is sacking through compression and reducing the overall spring stiffness.
The same thing happens if you adjust the rebound clicker to almost closed. The fork will initially feel stiffer, but once it travels enough to open the rebound valving, its return will be so slow the fork will begin to pack up and feel soft and mushy even though you have a "stiffer" setting.
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