Stock Silencer Clearance

[dmazz71]

Hi,

Is the rear tire supposed to slightly rub on the stock silencer on the KX500 when landing (small, not going 10 feet in the air) jumps?   The subframe seems to be straight as the rear tire is in the middle of it.  The bracket that holds the silencer to the subframe is also fine.

The two rubber bushings that are on the silencer are a little worn, but I didn't think that would matter?  Could the silencer be slightly bent? Not sure if this is normal or if something is out of alignment.

Thanks
Dan

[Goat]

The tire shouldn't come up that high on small jumps. Sounds like the shock needs rebuilt or the linkage bushings need replaced. It will rub on larger jumps as most bikes do, especially if you run a wide tire. Rubber bushings are pretty much there to get rid of vibration noise and to give the exhaust some flex to prevent breakage. If you can, throw some pics up.

[dmazz71]

Thanks for the reply.

I forgot to mention that I'm 200lbs, it that too much weight for the stock spring?  I haven't messed with the preload or anything on the suspension yet.  Is the linkage bushing the needle bearing that's on the swing arm?

[kxpegger]

Looks like it's just barely rubbing. Spacers?

[Polar-Bus]

I had the same issue running a 120 wide rear tire. I ended up using a stack of washers behind the bracket to space out the silencer about 3/8". 

[maddoggy]

the tire shouldn't be coming up that high on small jumps. i would say that you probably need to do some suspension tweeking. looks to be the compression is adjusted way too soft. i would start from scratch and start adjusting clickers till you get it right. you need to set the sag properly to start with. search "setting the sag" and find BDI's instructions and follow it to a t. you might also need to stiffen up the shock spring adjustment too. i am average height 5-11 and i can barely flatfoot when i sit on my bike. i have to lean on something or lean over a little to kick it over. my bike sits a little high but i never bottom out the bike. hope this helps

[dmazz71]

It does help, thank you.  It appears that all of the factory settings are set.  I'll start with the race sag, then mess with the rest.

Thanks
Dan

[Polar-Bus]

It does help, thank you.  It appears that all of the factory settings are set.  I'll start with the race sag, then mess with the rest.

Thanks
Dan

Just curious how much do you weigh ? KX's of the 90's inherantly were sprung on the soft side. So if you weigh more than say 165lb, you need stiffer springs.

[elmo]

When you sit on her and bounce does the back spring back up right away?

Or does the seat come back up slowly? could be your nitrogen pressure

[dmazz71]

I just measured the race sag and it looks like I need a stiffer spring.  It measured 4.5" and the collar is already about 3/4 of the way down the threads.

Thanks

[Polar-Bus]

I just measured the race sag and it looks like I need a stiffer spring.  It measured 4.5" and the collar is already about 3/4 of the way down the threads.

Thanks

That's too much sag. As a ballpark you want to be at 95-100mm ( 3.75"- 3.98" )

A quick way to tell if your spring is too soft is if you keep tightening your shock preload, and you can't achieve the desired sag measurement.

As a generall rule, lighter riders = slightly greater sag, and heavier riders slightly less sag. I have my sag set at 4.12"  but I only weigh 155 lbs

lastly, DON'T just add more compression to the shock clickers to compensate for too soft a spring rate, as this action drastically upsets the bikes bump absorbtion capabilities.

[dmazz71]

I think I may be able to get away with using the stock spring since I have another 1/2" of adjustment left on the spring.

Thanks
Dan

[DoldGuy]

As a general rule you continue to add preload to the spring to set your sag, but need to go stiffer on the spring if the bike has no "static sag" which means the bike should sag under it's own weight (no rider) when taken off of the stand.

[maddoggy]

yay! i finally posted up and didn't sound like an idiot for once! 

[dmazz71]

Thanks for all of your input guys.  I was able to get the sag to 3.75" and really feels like I'm on a totally different bike.

On top of adjusting the suspension, I also replaced the FMF Gnarley pipe (that came with the bike) with a stock pipe and installed a boyesen rad valve.  The rad valve really did give the bike an extra boost.  I also threw some VP street blaze 100 into her veins.  Not sure why I though I needed more power as I'm far from throwing this bike around.

Thanks again
Dan