Posts
2676
Joined
10/7/2009
Location
GB
Edited Date/Time
5/9/2016 8:31am
have any of you guys got first hand experience with modifying these forks to work well? heard a lot of people having problems doing so.
Looking at buying a new 350 soon, over here the ktms come with air forks, and the husky comes with the 4cs. Not a big fan of the design / idea of airforks. Would like some feedback from anyone that's spent some time setting the 4cs forks up- can you get them to work well?
thanks
Looking at buying a new 350 soon, over here the ktms come with air forks, and the husky comes with the 4cs. Not a big fan of the design / idea of airforks. Would like some feedback from anyone that's spent some time setting the 4cs forks up- can you get them to work well?
thanks
I've talk to several suspension tuners, who actually take out the entire 4cs system and replace it with Honda internals (again, cost to do that is about $1500-$1700).
The 4cs forks are the reason I'm not buying a KTM this year, it's hard to justify spending $10K on a bike and then needing to spend another $2K just to make the suspension ridable. (Unless they fixed them on the 16 models...and I'm anxiously waiting for some tests to be posted).
(Oh, for the record, I'm speaking from an off road perspective...on the XC/XC-F KTM's. I haven't done any research on the SX/SX-F models...and I'm not sure how different the suspension is between the two lines.)
I actually think the 4CS can be made to work very very well with some minor mods. Stock they leave much to be desired and I don't think anyone will disagree with that. We've tried modifying them into open chambers and these do work better than stock but I still think they work best at the stock 4CS setup with some internal modifications. Some valve modifications, remove the check valves and install low speed compression adjusters. This basically sets them up into a normal configuration where compression is on the bottom and rebound on the top. The added costs for these mods costs ~$200, which compared to other options is a huge savings.
These forks have a huge range of adjust-ability but this is also a double edged sword. We have many customers who send in their stuff because it's unrideable and most of it is because they don't have a good understanding on how to setup suspension. When valved/sprung correctly they're awesome but try to push them outside of where they're setup, they can be a bitch. You will likely need to have them at least revalved because like you've heard, stock they're not very good.
As far as replacing the internals... I wouldn't do it unless I did it with Ohlins. They've been around for awhile, they have a solid R&D program, they're designed for the specific application, you can reset them easily to stock and they're cheaper than the other options. I just wonder what will happen when/if this KYB/Showa fad fades away, your tuner leaves or you decide to go with someone else? We certainly want to test them out for ourselves but until then, we think that the 4CS is plenty good for 98% of the riders.
I'm not going to spam who I work for/with but if you're interested, PM me and I'll get you some info. Hopefully this helps some.
TLDR: 4CS aren't good stock but can be made to work very well with minor mods. Don't believe all the negative hype.
The Shop
If you like everything about the KTM 350, I wouldn't let that turn you off from buying it...
I just find it telling when guys who eat, sleep, and breath orange are almost universally complaining about the 4cs. That means they are really bad.
And I'm absolutely serious when I say they are the reason I'm not buying a KTM this fall. If I'm spending almost $10K on a bike (a purpose build off road bike, mind you-XC) I'd better be able to make the stock forks work. As it sits, I'll be on either a YZ or KX 450...whichever one I can get the best deal (cheapest) on.
In no way shape or form do you have to spend that kind of coin to make them work. A revalve with proper spring rates and I bet anyone would be more than happy.
I agree, you just need to ride the forks and create your own opinion on them.
If you like them, though, then you are in the VAST minority of everyone else I know, and have read online.
I know many riders that have been on KTM for years, and are jumping ship because they don't like the 4cs forks.
Anyway, I'll trust the masses, and say they suck....with the disclaimer that I'm not speaking from personal experience. (I've just done a ton of research on them, read as many reviews, and test as I can...and they all, overwhelmingly, have one thing in common, the forks suck. And that's good enough for me, and my money. I'll buy another brand until KTM figures them out and the masses change their mind.)
Pit Row
Go look up Tim Badour: he rode the bike at Pala on the big track and LOVED them.
(3).10x28mm
(1).20x26mm
(1).25x24mm
(1).25x22mm
(2).25x20mm
mid valve
(5).10x17mm
(1).10x16mm
(1).10x14mm
(1).10x13mm
Can't imagine why they feel like crap stock...
On the internet everything sucks from rainbows to winning the lottery.
After I got mine set up by ENZO for my weight, riding skill, local tracks etc I think they are great forks.
1/ The 4 cs design is a money saver for the Factory
2/ the 4cs is slightly lighter than twin chamber
3/ the 4cs is no better design than the forks we had back in the very early 2000's
I was told 4cs was "loosely based" on a Ohlins TTX but "cheaper to make" I think it is much like the 2003/4
Kawasaki KYB Bladder fork ( which was KYB's piss poor response to the Showa 47mm Twin Chamber fork back in the day ).
4/ The 4cs fork uses a 8mm steel damper rod (that is drilled for the adjustment rod) this rod can not possibly support the weight of the bike and transmit the forces required to control bottoming....that is why they had to modify the bottoming system on the 15's by drilling 4 big holes in the bottom of the cone and throwing away teflon seal and removing the shim damping control the first model had .
The Damping system they built is flawed and oil gets blown out of the lower chamber into the top because the seals and pressurization system are ineffective at high shaft speeds.... the WP engineers cut a groove in the damper rod to "equalize the two cambers when the bike is topped out and oil can migrate back into the damper tube....to FIx the problem...I call that hiding the problem... the real world result of the systems failings are if you hit several big bumps quickly the damping tube will blow out most of it's oil and totally lose damping constancy ( that is why everyone when over to the Twin Chamber pressurized system ten year ago!)
5/ WP totally removed the Bottoming System on the 16 ! You don't need it don't need it apparently.......use do smaller jumps you will be fine!...
6/ KTM feels the 4cs is ok for the level of most riders buying the bike and that pro riders will buy the Cone Valve kit stuff if they don't like it.
7/ As a former Magazine technical editor I cant believe the motorcycle press hasn't reported the issue with both the Air fork and 4cs forks accurately.... Every KTM or Husky supported rider runs Cone valves and even the lower level guys are running the 14 twin chambers or running 4cs and hating their forks!
8/ The KTM Husk and WP sales,technical guys and dealers will talk you blue in the face and say they are ok.
9/ Most Suspension tuners will tell you they have a "great setting" for the 4cs
10/ The 2nd 3rd or 4th Suspension tuner you got to will tell you "that guy who worked on your forks last time" is an idiot"
11/ Customers please vote with their $$ and buy the Yamaha this year because they are the only ones that havent t sold out yet to the " bugger the Customer lets make some money! The twin chamber stuff is too good for them anyway! crew.
12/ as for Air forks ..............they don work as well as the better twin Chambers.
13/ Air Forks......................They don't last very long with out expensive problems....you wont want to own a 2 or three year old air for bike unless your ready to spend a $1000 on new internals
14/ in closing wake up world your being ripped off with a cheep poorly developed product that is way inferior to what was industry standard 2 year ago...............
obviously we always get everything set up for me, correct springrates etc, but would never throw thousands on an already expensive bike, cant justify that!
the 2016 model bikes over here- ktm comes with air forks, the husky comes with 4cs, they are essentially the same bike other than that (few minor differences but the forks being the main one)
I do have a friend that has a 2016 ktm 350, going to ride that in a couple of weeks, but don't know anyone with a bike with 4cs forks that I can try, hence why I am trying to find any info I can on getting them set up
Im not that fussy with bikes, I can generally jump on someone elses bike and ride it fast straight away (sometimes I race my 87 cr 250 on the same day as my 350, and can go from one to the other relatively easily) - but I would be disappointed if I spent all that money on a new bike, for it to handle worse than my 2015 350 does
might be a quick, easy solution to the problem.
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