Hey all, Ive been trying to get my suspension dialed in on my 2007 250sx for awhile now, and Ive been having some difficulties. Ive been wondering what the difference is between hi speed and lo speed compression on the rear shock. At what point are you using hi speed compression? Braking bumps? Rocks? Are whoops and landings lo speed? Right now I have my high speed compression completely backed off, and the rest of the clickers adjusted to the point where I bottom my suspension 3-4 times a ride, and the suspension still feels extremely harsh compared the all of the cr's Ive owned. The springs are very close to the correct rate, very slightly soft if anything, according to the race tech calculator. I'm having a very hard time just getting the suspension to the point where I feel comfortable on it. Does anybody have any recommendations? It would be greatly appreciated, Im trying to get the bike ready for a hare scramble this coming weekend.
Hi speed v. lo speed compression
Started by
VE290
, Jul 02 2012 08:28 AM
36 replies to this topic
Posted 02 July 2012 - 07:12 PM
As I ws explained to , the high speed compression is actually the shock shaft speed, ?? Me too. They explained it is adjusted for say a square edged bump in which appraching the bump the slow speed valve is taking the rollers, then when you hit the square edge bump witch drastically increases the ( shock shaft ) speed. this portion takes over for a second to keep the rear from bottoming.
My understanding.......
If the bike feels too harsh on downstroke, in front at least, you may try using a thinner oil, or reducing the oil level in the fork. for the rear , it may be time to service the shock.
A revalve would b the last thing I would do.
hope this helps a little.
Al
My understanding.......
If the bike feels too harsh on downstroke, in front at least, you may try using a thinner oil, or reducing the oil level in the fork. for the rear , it may be time to service the shock.
A revalve would b the last thing I would do.
hope this helps a little.
Al
Posted 02 July 2012 - 08:15 PM
The stock KTM WP shocks from that era kinda suck. The pistons have little tiny ports so no matter what you do, it doesn't flow enough oil. The solution is to have someone install an updated piston kit, shim it properly for the type of riding you will be doing and insure you've got the right spring.
Yes, you can work-around the problem until your blue in the face, changing springs, messing with the clickers, etc... but in the long run, nothing is going to "fix" it, until you actually start making BIG changes. I have spent a great deal of time working on that exact shock of recent and its impossible to make it work right stock in my view. WP updated it in 2011, but the updated piston kit is widely available.
High speed compression reacts through things like breaking bumps and sharp kickers, where low speed reacts over small chop.
The "adjusters" don't do very much in all honestly. They are simply bypass valves and there is only so much they can bypass.
On the WP shocks, the key is getting the right spring rate, having good balance with the bike and then messing with the piston/shim stack to dial it in. You will never dial it in with the clickers sadly. Its important to also understand that unlike the linked bikes, the PDS relies on its valving and spring almost 50/50. So if you don't have the right spring (correct preload) and you don't have good oil, it will feel really bad.
Yes, you can work-around the problem until your blue in the face, changing springs, messing with the clickers, etc... but in the long run, nothing is going to "fix" it, until you actually start making BIG changes. I have spent a great deal of time working on that exact shock of recent and its impossible to make it work right stock in my view. WP updated it in 2011, but the updated piston kit is widely available.
High speed compression reacts through things like breaking bumps and sharp kickers, where low speed reacts over small chop.
The "adjusters" don't do very much in all honestly. They are simply bypass valves and there is only so much they can bypass.
On the WP shocks, the key is getting the right spring rate, having good balance with the bike and then messing with the piston/shim stack to dial it in. You will never dial it in with the clickers sadly. Its important to also understand that unlike the linked bikes, the PDS relies on its valving and spring almost 50/50. So if you don't have the right spring (correct preload) and you don't have good oil, it will feel really bad.
Posted 02 July 2012 - 08:16 PM
Just4fun Racing, on 02 July 2012 - 08:28 AM, said:
Hey all, Ive been trying to get my suspension dialed in on my 2007 250sx for awhile now, and Ive been having some difficulties. Ive been wondering what the difference is between hi speed and lo speed compression on the rear shock. At what point are you using hi speed compression? Braking bumps? Rocks? Are whoops and landings lo speed? Right now I have my high speed compression completely backed off, and the rest of the clickers adjusted to the point where I bottom my suspension 3-4 times a ride, and the suspension still feels extremely harsh compared the all of the cr's Ive owned. The springs are very close to the correct rate, very slightly soft if anything, according to the race tech calculator. I'm having a very hard time just getting the suspension to the point where I feel comfortable on it. Does anybody have any recommendations? It would be greatly appreciated, Im trying to get the bike ready for a hare scramble this coming weekend.
Think of "high speed" and "low speed" in terms of the speed your wheel is moving in response to an obstacle or a shift in weight. For example, landing a jump or hitting a curb are high-speed suspension events. Braking or accelerating apply a load gradually to the fork or shock and are low-speed events. The suspension on your 250SX can be improved, but you will likely need help from a tuner.
Posted 03 July 2012 - 04:09 AM
Just4fun Racing, on 02 July 2012 - 08:28 AM, said:
Hey all, Ive been trying to get my suspension dialed in on my 2007 250sx for awhile now, and Ive been having some difficulties. Ive been wondering what the difference is between hi speed and lo speed compression on the rear shock. At what point are you using hi speed compression? Braking bumps? Rocks? Are whoops and landings lo speed? Right now I have my high speed compression completely backed off, and the rest of the clickers adjusted to the point where I bottom my suspension 3-4 times a ride, and the suspension still feels extremely harsh compared the all of the cr's Ive owned. The springs are very close to the correct rate, very slightly soft if anything, according to the race tech calculator. I'm having a very hard time just getting the suspension to the point where I feel comfortable on it. Does anybody have any recommendations? It would be greatly appreciated, Im trying to get the bike ready for a hare scramble this coming weekend.
If it were me, I would try this. Start with your rebound. It affects your compression as well and rebound. If your rebound is too fast it can jack around
with your high speed setting. High speed is your shaft speed. So once you get your rebound set. Go to your high speed and start adjusting.
I noticed high speed adjustor can affect your ride height as well to a degree. So currently, you have your high speed backed completely off, so your
are riding in the lower part of the stroke. You have to find a balance there. Go 1 to 1.5 turns in on the high speed after you ajusted the rebound.
hope this helps.
jw
Posted 03 July 2012 - 01:51 PM
tye1138, on 02 July 2012 - 08:15 PM, said:
The stock KTM WP shocks from that era kinda suck. The pistons have little tiny ports so no matter what you do, it doesn't flow enough oil. The solution is to have someone install an updated piston kit, shim it properly for the type of riding you will be doing and insure you've got the right spring. Yes, you can work-around the problem until your blue in the face, changing springs, messing with the clickers, etc... but in the long run, nothing is going to "fix" it, until you actually start making BIG changes. I have spent a great deal of time working on that exact shock of recent and its impossible to make it work right stock in my view. WP updated it in 2011, but the updated piston kit is widely available. High speed compression reacts through things like breaking bumps and sharp kickers, where low speed reacts over small chop. The "adjusters" don't do very much in all honestly. They are simply bypass valves and there is only so much they can bypass. On the WP shocks, the key is getting the right spring rate, having good balance with the bike and then messing with the piston/shim stack to dial it in. You will never dial it in with the clickers sadly. Its important to also understand that unlike the linked bikes, the PDS relies on its valving and spring almost 50/50. So if you don't have the right spring (correct preload) and you don't have good oil, it will feel really bad.
Some more information, the suspension was revalved by race tech. I talked to the mechanic who sent it out for previous owner, and he said previous owner was almost the same weight/ height as myself. Oil is around a month old in both shock and forks, with the recommended amount of oil. Also, springs are correct for me. What your saying about the ports really makes sense. Ive talked to a lot of other people who have the same problem. I'll talk to the mechanic at the shop about replacing the piston. Thanks for the input!
Posted 03 July 2012 - 01:55 PM
jwaseman, on 03 July 2012 - 04:09 AM, said:
If it were me, I would try this. Start with your rebound. It affects your compression as well and rebound. If your rebound is too fast it can jack around with your high speed setting. High speed is your shaft speed. So once you get your rebound set. Go to your high speed and start adjusting. I noticed high speed adjustor can affect your ride height as well to a degree. So currently, you have your high speed backed completely off, so your are riding in the lower part of the stroke. You have to find a balance there. Go 1 to 1.5 turns in on the high speed after you ajusted the rebound. hope this helps. jw
Right now, I have my rebound clickers all set in the middle of the adjustment. I can tell a difference when I do adjust them, but I dont really have any preference on how they're adjusted i guess, unless it rebounds too quickly or way too slow. I have my High speed set no 1.5 turns out now, and I can tell no difference between this and completely backed off. Thank you for the input though, I never knew rebound could affect the compression, good to know.
Posted 03 July 2012 - 02:19 PM
Just4fun Racing, on 03 July 2012 - 01:51 PM, said:
Some more information, the suspension was revalved by race tech. I talked to the mechanic who sent it out for previous owner, and he said previous owner was almost the same weight/ height as myself. Oil is around a month old in both shock and forks, with the recommended amount of oil. Also, springs are correct for me. What your saying about the ports really makes sense. Ive talked to a lot of other people who have the same problem. I'll talk to the mechanic at the shop about replacing the piston. Thanks for the input!
Did race tech put their pistons in it? Thats the big question...
Posted 06 July 2012 - 07:55 AM
tye1138, on 03 July 2012 - 02:19 PM, said:
Did race tech put their pistons in it? Thats the big question...
Im pretty sure it was just the valves. How much does a new piston kit cost? Do i have to send my suspension to race tech to have it done? I can barely change my own seals so I certainly won't be doing myself lol. I spent all day yesterday and the day before trying to get the suspension close to functioning, and wound up going over the bars while i had my clickers set all the way to soft! Still feels no better... Maybe i'll just get another cr...
Posted 06 July 2012 - 12:01 PM
Just4fun Racing, on 06 July 2012 - 07:55 AM, said:
Im pretty sure it was just the valves. How much does a new piston kit cost? Do i have to send my suspension to race tech to have it done? I can barely change my own seals so I certainly won't be doing myself lol. I spent all day yesterday and the day before trying to get the suspension close to functioning, and wound up going over the bars while i had my clickers set all the way to soft! Still feels no better... Maybe i'll just get another cr...
I'm not sure of the cost to do anything with race tech, I don't use them.
I highly suggest sending the shock and forks to John @ MotoPro and having him do his thing. He'll replace the base valve (compression valve) with something that works a lot better. He'll also re-work the shim stack so it works. His piston kit for the shock is awesome, its an entirely different feel, especially with the bladder kit.
KTM's biggest weakness is the suspension. Sadly, MOST tuners, haven't got a clue how to tune it properly. PDS is very tricky, it has a lot of elements which need to be spot-on and when it is, the bike works well. It just takes a while to get it spot on and just because it works at one track, doesn't mean it will work at another...
Posted 06 July 2012 - 12:42 PM
Just4fun Racing, on 03 July 2012 - 01:51 PM, said:
Some more information, the suspension was revalved by race tech. I talked to the mechanic who sent it out for previous owner, and he said previous owner was almost the same weight/ height as myself. Oil is around a month old in both shock and forks, with the recommended amount of oil. Also, springs are correct for me. What your saying about the ports really makes sense. Ive talked to a lot of other people who have the same problem. I'll talk to the mechanic at the shop about replacing the piston. Thanks for the input!
Posted 09 July 2012 - 08:08 AM
YHGEORGE, on 06 July 2012 - 12:42 PM, said:
The previous owner or the local mechanic should have a receipt detailing what was done. I very seriously doubt that RT revalved the shock and did not replace the piston but you should ask about this before you do anything else. KTM stuff can be difficult but I think you should spend a good bit of time having someone local help you with well thought out adjustments. There should be someone familiar with ktm and suspension at the hare scramble who would be willing to help. Don't just start throwing hard earned dollars at something you really don't understand yet. I'll bet you can get close with what you have.
It sounds like race tech did put in their piston, but it might be the motocross oriented piston? Your certainly right that i don't understand this, but I talked to some guys at a race this weekend who tried to help me out. We adjusted all the clickers as soft as possible, hi speed 1.5 turns in, rebound on forks all the way out, and rebound on the shock about midway. Still sucked, so we bled my forks to have negative pressure, which supposedly makes it a lot softer, but it was still very harsh. Still bottomed out too.
tye1138, on 06 July 2012 - 12:01 PM, said:
I'm not sure of the cost to do anything with race tech, I don't use them.
I highly suggest sending the shock and forks to John @ MotoPro and having him do his thing. He'll replace the base valve (compression valve) with something that works a lot better. He'll also re-work the shim stack so it works. His piston kit for the shock is awesome, its an entirely different feel, especially with the bladder kit.
KTM's biggest weakness is the suspension. Sadly, MOST tuners, haven't got a clue how to tune it properly. PDS is very tricky, it has a lot of elements which need to be spot-on and when it is, the bike works well. It just takes a while to get it spot on and just because it works at one track, doesn't mean it will work at another...
I highly suggest sending the shock and forks to John @ MotoPro and having him do his thing. He'll replace the base valve (compression valve) with something that works a lot better. He'll also re-work the shim stack so it works. His piston kit for the shock is awesome, its an entirely different feel, especially with the bladder kit.
KTM's biggest weakness is the suspension. Sadly, MOST tuners, haven't got a clue how to tune it properly. PDS is very tricky, it has a lot of elements which need to be spot-on and when it is, the bike works well. It just takes a while to get it spot on and just because it works at one track, doesn't mean it will work at another...
I'm really thinking about buying a new bike because of this. Last weekend I rode motocross, this weekend I rode a rocky, technical hare scramble, and next weekend I'll be doing an 80 mi desert race with big sandy whoops at 50 mph. Im getting the impression that theres really no way to make my suspension function well in all of these terrains. I have heard good things about bladder kits though. I really just want to get another CR, but i havent seen one for sale anywhere nearby in ages.
Posted 09 July 2012 - 09:10 AM
a yz250 would do that far far better than the ktm but its a tall order
Posted 09 July 2012 - 12:27 PM
mog, on 09 July 2012 - 09:10 AM, said:
a yz250 would do that far far better than the ktm but its a tall order
I've never ridden a yz, but I absolutely love the gen 3 hondas. Problem is finding one for sale. My family is into the honda 2t's, so i grew up on them, and still race them in team races with my uncle. Ive seen a few more yz's on craigslist, but I'm a bit reluctant to try a new bike again. I would rather stick to what I know.
Posted 09 July 2012 - 04:59 PM
I have a buddy who just bought an 04 CR250 and loves it. Even with the stock suspension, which is years old, the thing works great. He just went and rode the KTM demo day with the new 2013 bike lineup and said they were horrible compared to his CR.
Mind you, I DO feel you can make the KTM's perform well. However, they do require a bit more tuning for sure, especially the PDS bikes.
Mind you, I DO feel you can make the KTM's perform well. However, they do require a bit more tuning for sure, especially the PDS bikes.
Posted 09 July 2012 - 06:15 PM
tye1138, on 09 July 2012 - 04:59 PM, said:
I have a buddy who just bought an 04 CR250 and loves it. Even with the stock suspension, which is years old, the thing works great. He just went and rode the KTM demo day with the new 2013 bike lineup and said they were horrible compared to his CR.
Mind you, I DO feel you can make the KTM's perform well. However, they do require a bit more tuning for sure, especially the PDS bikes.
Mind you, I DO feel you can make the KTM's perform well. However, they do require a bit more tuning for sure, especially the PDS bikes.
I had an '04 cr125, by far my favorite bike I have ever ridden. And I'm sure KTM's can perform well, most off the fastest off-road guys in the world ride them. However, I don't have confidence I can get mine to perform well consistently in such varied terrain. At least not when compared to a CR, or, from what I hear, a YZ. I would also have to put 500+ dollars to make it feel as good as an '07 cr250 does out of the box. Which is all fine, but I'm not able to find a CR for sale. So KTM it is, for now I guess.
Posted 09 July 2012 - 07:57 PM
I think a lot of guys ride KTM's for the chassis/motor/geometry rather then the suspension. I think the WP components just don't work anywhere near KYB or Showa. Its more to do with coatings and tolerances, rather then poor design. I personally like KTM's because with their 2 stroke lineup, they tend to build the best over-all packages. Sure the suspension needs work, but you can ride around a lot of issues if you build the suspension well enough.
Once you figure out what works and what doesn't work through experimenting, then you should be able to dial in that KTM with no problem. It just takes some time and patience.
Once you figure out what works and what doesn't work through experimenting, then you should be able to dial in that KTM with no problem. It just takes some time and patience.
Posted 11 July 2012 - 12:18 PM
tye1138, on 09 July 2012 - 07:57 PM, said:
I think a lot of guys ride KTM's for the chassis/motor/geometry rather then the suspension. I think the WP components just don't work anywhere near KYB or Showa. Its more to do with coatings and tolerances, rather then poor design. I personally like KTM's because with their 2 stroke lineup, they tend to build the best over-all packages. Sure the suspension needs work, but you can ride around a lot of issues if you build the suspension well enough.
Once you figure out what works and what doesn't work through experimenting, then you should be able to dial in that KTM with no problem. It just takes some time and patience.
Once you figure out what works and what doesn't work through experimenting, then you should be able to dial in that KTM with no problem. It just takes some time and patience.
I do love the power and ergonomics of my KTM. However, the suspension issue is killing me. I just found a cr for sale though, and I think I'm going to buy. I really do like my KTM, and they definitely have the jap 2 strokes beat when it comes to most things, but personally, I feel more comfortable on a Honda.
Posted 11 July 2012 - 01:06 PM
Honestly, you can fix the KTM suspension, it just takes work. You will never make it better then a CR without replacing the actual components, but you can for sure make it acceptable. I'm thinking about just going Öhlins all the way around for my next KTM because I'm so sick and tired of dealing with WP crap. I don't want stuff thats OK, I want stuff thats exceptional and nothing WP makes seems to fit that description sadly.
