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A lttle help on Ohlins topping out

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I have a KTM 450 sx with Ohlins cartridge. The forks were set up for hare scrambles. I started riding mx again after a few years of hare scrambles. As my confidence began to improve and my speed and jumpability increased the forks seemed to blow thru the stroke but didn't bottom. I believe the clickers were set on 8 comp, and 8 on reb. Oil level at 350cc and springs are 51's. I had the forks revalved for mx. The only change was to the clamping shims. I believe the last three were changed to 1 mm larger diameter. The clickers were changed to 16 comp 8 reb and everything else the same. The forks were much better and didn't blow thru the stroke. That's when I noticed the forks felt funny. It took me a little while to narrow down what I was feeling. I have determined that the forks are topping out on take off and when landing the initial contract with the ground they seem to have little resistance for the first inch or so. I have taken the forks apart and the rods on both cartridges seem to operate smoothly and fully extend when pushed in. I have not taken the cartridges apart. The spring preload is set at zero as per Ohlins manual. My local dealer thinks its a spring rate preload problem. I did try increasing the reb to 5 today but cant really say it improved my problem but it didn't seem to handle as well so I returned to 7 out. I have an oring on lower tube and I am about a inch away from bottoming same as before the revalve. Any help will greatly appreciated. I am getting more and more worried when jumping. Thanks Ron

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You have done a good job of looking for the problem , I can't think why it would do that , given zero preload and you have added rebound with no improvement

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Do your cartridges have the 2014 style top out springs?? Maybe the addition of these parts could be a fix .. Along with the new mid valve spec while your at it!!

Sent from my iPhone using Thumper Talk

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Do your cartridges have the 2014 style top out springs?? Maybe the addition of these parts could be a fix .. Along with the new mid valve spec while your at it!!

Sent from my iPhone using Thumper Talk

They are currently out of stock of the top out spring & sleeve, as I have some on order as well for a customer. 

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How much do you weigh? What year of bike is it (PDS or linkage?), and what year of the forks?

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Getting forks back from Harry. He said that the pressure was low in the chambers and causing cavitation. He also added a little more rebound.

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I'm also having problems with my 2014 Ohlins RFX forks topping out. I race MX only and it starting doing it 2 wks ago after never doing at all so I'm very confused by it. I raced a track that had 3 very long jumps with super steep take offs and you had to be going very fast to clear them. I jumped them most of the day but on those jumps as I drove into the face the forks would bottom (not badly) and then unload right as I took off and then top out. I didn't know what to make of it. They had a new dozer operator that weekend and the take offs on those jumps felt to be almost straight up and very much like a supercross jump. I rode this weekend and a local practice track and they only way I was able to get the forks to top out was to literally pull back hard on the bars when leaving the face of a cpl of the bigger jumps at this track. This is definitely new and my forks had never done it before.

Edited by Mike_DeGaetano

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Getting forks back from Harry. He said that the pressure was low in the chambers and causing cavitation. He also added a little more rebound.

do they have a pressurised separator piston like the ttx?

let us know if its fixed!

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Yes, Dean definitely fixed my top out issue because I had a friend with the same bike and 14 RFX forks and the same fork springs as I'm running come with me the day Dean came up here and I rode his bike after Dean made the changes to my forks and I could make his forks top out on a particular jump at our track and mine would no longer top out on that jump no matter how hard I tried to get them to do it. Problem solved :-)

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