KDXRIDER.NET

My front end kicks out violently when I go over bumps and hills quickly and makes a loud smash, as if the springs are pushing out the outer tubes and hitting something metal. It is a very "springy" ride and feels very sloppy into corners and over bumps. I have stiffer springs set to my weight, fork emulators, switched from 10w to 5w oil, and have the correct oil amount in each fork (book says 138mm standard) so I got a measuring cup and measured out 138mm. What do I need to adjust or fix in order to have a stiffer, plush ride?

Would I need to modify my shim stacks and if so how would I do that?

I think the measurement of oil in the book is refereing to the distance from the top of the fork tube to the oil in the fork. Not the total volume. You probably do not have enough oil in the forks.

thats what I was thinking. Compared to how much oil that came out when I drained the forks, 138mm isnt enough. Btw would different weight of oil affect damping also? But even before I changed out the oil, the front end was still pretty harsh over bumps and hills

OK, here is how you can measure it on the cheap. Just make a rod and put marks on the side of it in millimeters at about the desired height of oil you want. In your case I would probably make marks from 130mm up to 150mm. Make sure you have the forks perfectly vertical. The only way to do this is to remove them from the bike. Trying to do it at an angle is just a PITA. Make sure the springs are removed and the fork fully compressed before adding oil. Then fill to the level you wish using your little dipping stick!



Different weight oils will affect damping, both compression and rebound. It is a fine balance you must make between soaking up the big stuff yet still have a ride that isn't harsh on the small stuff. good luck as it really is personal preference and the only way to find out what you like is to try them!

>|QBB<[/url]

SS109 wrote:OK, here is how you can measure it on the cheap. Just make a rod and put marks on the side of it in millimeters at about the desired height of oil you want. In your case I would probably make marks from 130mm up to 150mm. Make sure you have the forks perfectly vertical. The only way to do this is to remove them from the bike. Trying to do it at an angle is just a PITA. Make sure the springs are removed and the fork fully compressed before adding oil. Then fill to the level you wish using your little dipping stick!



Different weight oils will affect damping, both compression and rebound. It is a fine balance you must make between soaking up the big stuff yet still have a ride that isn't harsh on the small stuff. good luck as it really is personal preference and the only way to find out what you like is to try them!

wow, this is really helpful! do I stick the tubing all the way to the bottom of the inner tube to measure? Iv'e heard multiple times on this site about making our own oil gauge tools but never saw any instructions or pictures. I had 10w oil in my forks before I switched to 5w, I think I'll stick with 10w. I've also heard on this site about removing half the shims in the shim stack, but how would this help suspension performance?

EDIT* I looked at the diagram again and realized I need to keep the top of the tubing even with the top of the fork and just measure to the oil level

Yeah, the measurement is from the top of the tube (without cap) down to the oil. You were shooting for 138 millimeters, so, down to your oil should be 138mm.

As for the shim mod, that is normally reserved for KX fork conversions as they are valved for MX action and not for trail. If you are running stock forks I personally wouldn't mess with it. However, maybe someone more knowledgeable will come along and be able to give some tips on tuning the shim pack.

FYI, some have used Mobil 1 synthetic automatic transmission fluid as a replacement for standard fork oil in the stock forks with good results and it is a lot cheaper! It is right around 7.5w.

Here is another thread about making your own fork oil level tools:

http://kdxrider.net/forums/viewtopic.ph ... highlight=

Tedh98 wrote:Here is another thread about making your own fork oil level tools:

http://kdxrider.net/forums/viewtopic.ph ... highlight=

Lots of ideas here, thanks man

And mobil 1 automatic transmission fluid, hmmm. I'll probably try it out today haha, definitely a lot cheaper and it's available in more places other than dealerships

But any ideas why my front end kicks out violently? Could it only be oil level that's effecting it?

KDXrider1989 wrote:But any ideas why my front end kicks out violently? Could it only be oil level that's effecting it?

I would take it one step at a time. Get the oil level set and then see what else is going on.

rbates9 wrote:

KDXrider1989 wrote:But any ideas why my front end kicks out violently? Could it only be oil level that's effecting it?

I would take it one step at a time. Get the oil level set and then see what else is going on.

Yep, one step at a time!

So I got some Mobil1 synthetic ATF today for my front forks, they are rated at Dexron 6. Think this would work?

http://img59.imageshack.us/i/c48764327a ... x0600.jpg/

KDXrider1989 wrote:So I got some Mobil1 synthetic ATF today for my front forks, they are rated at Dexron 6. Think this would work?

http://img59.imageshack.us/i/c48764327a ... x0600.jpg/

That's the stuff. Like I said early, the weight is supposed to be right at 7.5. It should be a good compromise between the 5 and 10wt.

Great refresher!

awesome, thanks yall btw SS109, how's the rebuild going?

KDXrider1989 wrote:awesome, thanks yall btw SS109, how's the rebuild going?

Your welcome. As for my build, it is stalled for the moment. The head on my car blew, and with the money I spent picking up the KDX250, I can't really do much else at the moment.

ahh that blows, but at least you got that nice 250 for cheap. I cant wait to see the white 200 finished