Grease zerks on rear suspension (long w/pics)

[Hellbender]

Here's my attempt at zerking (is that a word???) the rear suspension linkage & swingarm bearings.

I really don't want to get into a debate on whether zerks work or it's best to dissassemble and grease, etc., etc., etc. That seems to have been discussed pretty well on the forum.

I'm a dumb old country boy and on the farm, grease (& lots of it), was the only way to keep equipment running and working; so I like the ability to easily grease after every wet, sloppy ride.

I didn't want to simply add a zerk and HOPE that the grease gets to both bearings or possibly blow a seal by overpressuring with grease.

I used three different methods to accomplish my goal for each of the different bearings. The zerks pictured were actually changed to 90 deg type after the pics were taken.

Method #1-- used for 3 each paired swingarm bearings & 1 each paired bearing in linkage (for forward connection point of tierods)

Drill for grease INPUT (zerk) centered directly between the 2 paired bearings....

http://www.toughstuffproducts.com/box4/zerks6.JPG

Then drill 2 each 1/16" diameter holes for grease OUTPUT directly across from the INPUT hole & located between each bearing and the outer seal, ie.... the grease travels from the INPUT hole diagonally THROUGH the bearing to release at the OUTPUT hole.

http://www.toughstuffproducts.com/box4/zerks5.JPG
http://www.toughstuffproducts.com/box4/zerks9.JPG
http://www.toughstuffproducts.com/box4/zerks10.JPG

Method # 2 used for forward paired bearings in the linkage....
These bearings are pressed together so there is no gap between them (ie can't send grease that way)

This is a little more complicated, first cut two slots in the sleeve w/ an abrasive disc (dremel tool) for grease passage.

http://www.toughstuffproducts.com/box4/zerks1.JPG

Next center drill the bolt for a zerk and cross drill for grease passage (I show both the easy and hard way) .

http://www.toughstuffproducts.com/box4/drill%20bolt2.JPG

http://www.toughstuffproducts.com/box4/drill%20bolt.JPG

Now drill the 2 small OUTPUT holes between the bearing and seal.
http://www.toughstuffproducts.com/box4/zerks7.JPG

Method # 3 used for lower shock bearing

Drill INPUT diagonally to enter space between seal on 1 side (miss a little to the inside and file a small groove to channel the grease to the area between the seal and bearing)

http://www.toughstuffproducts.com/box4/zerks2.JPG

Drill OUTPUT on opposite side so grease releases through bearing.
http://www.toughstuffproducts.com/box4/zerks4.JPG

Grease with a HAND pump only (slowly) to allow grease to penetrate through bearing, an air powered type hits too fast and may blow a seal.

If grease only comes through 1 output hole, just hold your finger on it until grease comes out the other.

The OUTPUT holes are always full of grease so nothing can enter there, and if the ENTIRE space between seals is packed w/ grease, there is no place for water to get into.

My thoughts anyway, I may be wrong, but it was a fun project!

HB

 

[m0rie]

HellBender,

Thats a nice writeup with good pictures. I've seen a few attempts at installing grease zerks on the KDX but yours in the first i've seen that actually looks like it would work as its intended too. I'll be waiting to see how your bearings hold up since they'll be re-greased every ride. Keep us posted.

-Maurice

 

[Hellbender]

Maurice- thanks for the compliment, I've had 3 KDX's in the last year, a '95, a '97 (both beaters) and bought a nice '02 about 2 months ago after I decided the KDX was the bike I really wanted.

Seems that all the KDX's I looked at (6 or 8) have bearings shot in the rear suspension, my 02 looked perfect and upon disassembly 2/3 of the bearings were bad.

I tested my grease "fixes" above by totally removing all grease from each bearing w/ brake cleaner, reassembling them dry and then shooting them full of grease and disassembling. Every bearing was totally packed, so they seem to work as I intended.

The lower shock bearing will be the first indicator, as they only seem to last 6 months or so, no matter what you do.

HB

 

[John Harris]

Does anyone know how these procedures affect the integerity of the unit? Will parts of it crack or break under hard use with the holes in it? A snap on landing from a jump could be pretty rough for instance.
I am all for the lubrication and think this is a neat idea. Does anybody have any thoughts or experience on how it will afftect safety and reliability?
Cheers John

 

[Hellbender]

John--good question. Here's my thoughts (I'm a mech. engineer, so please don't hold that against me :moon: ), for whatever they're worth.

Any engineer worth his salt (& the Jap's are pretty sharp) would figure in at LEAST a 200% safety factor in a component such as this. The small amount of material removed would fall well inside this margin. Also, the material used is a relatively soft, ductile aluminum alloy. This material should deform visibly before catastrophic failure, unlike a harder, more brittle alloy which would possibly crack or break a chunk out (instead of stretch or deform) under an abnormally high impact load.

Sounds good to me anyway......... but you know what free advise is worth :coocoo:

HB

 

[kx250kev]

Nice work Hellbender. Here's a thought....go into biz doing this mod for people. ;) Hey, many send their cylinder out for porting, why not this... :cool:

 

[demographic]

I know this is dragging up an old thread but I've just done a search with the words "Grease" and "Zerk" and this was one of the threads it turned up, I'm fairly sure I read it way back when but couldn't find it till now.
It's is also about the best looking design for adding them as far as I can tell.

As its five years on from the thread being started and Hellbender might have had a great chance to see how it works in the long term, so err....

Hows it worked then? Any problems or changes to the design?

 

[julien_d]

Hrm. Since Mr Hellbender's last post here was in 2005, I think it's safe to say he hasn't visited this forum in quite some time. Looks to me like it would work quite well.

 

[mudpack]

I like the idea of gease zerks; seems it would encourage us to lubricate those bearings more often than if we had to disassemble every time. The only part I don't care for is the extra 1/16" holes 'bender drilled to allow the grease to exit the bearing. It is not necessary, and provides another easy entry for water. (I often find myself in water 18" deep)
Just put the zerks on and grease away!....the excess grease will be expelled through the seals just fine.

Would have been nice if he'd given the drill and tap sizes for the zerk holes....might have saved us some research.

 

[glad2ride]

On the older models, the mounting bolts were hollow. The sleeves were as well, allowing the grease onto theinner surface of the needle bearings.

 

[Tom68]

Fitted grease nipples to my 250sr 3 years ago, no failures. Due to strip and inspect when I get some time.