KLX250/300 – fitting new fork springs

[Mark FalveyMember]

This isn’t the only way to do it, but if I did the job again, barring Lotto wins, this is how I’d go about it. As far as my iffy measurements (or lack thereof) go, NASA probably wouldn’t do it the way I did (Garuda probably wouldn’t do it at all) but as a friend of mine said “needs must when the devil sh*ts in your face”.

I used:

Tools
long and short breaker bars
8,10,30mm sockets (Repco do a 30mm for $14.50)
6mm 1/2′ allen drive
12,17mm ring spanners
17mm open end spanner

Stuff
clean rags
tie wire
300mm cable tie
bike stand (aka milk crate with 40mm wood bolted on)
ocky straps
loctite
clean clothespeg
clothes airer (yep, really)
City of Yarra wheelie bin
scrap 12mm mdf
drain container for old oil
vernier calliper
coffee (of course)
1000ml 5w fork oil
measuring container (500ml)
new springs

1. bike on the stand

2. undo the bar clamp and hang the bars over the headlight surround; an ocky strap will stop the sliding around

3. front wheel out, speedo drive out of the way, brake calliper removed and hung by tie wire from a nearby indicator. This seemed to dislodge a bubble and the braided line is really kicking in!

4. fork shrouds off

5. the air valves on the fork caps get in the way, so I swapped the screws back on

6. loosen the upper clamp pinch bolts a little and crack the caps – easier with them on the bike

7. slacken off the pinch bolts and lower a fork leg free.

8. put the scrap wood on the ground, a rag over it then stand the fork leg upright. Roll the bin up to it and lash them together firmly with the cable tie.

9. when the cap’s free, boost the fork leg up from below by 100mm or so (width of my scrap wood) to expose the spring, nut and shaft. I had nothing to cobble up a spring compressor out of so I bodged along by slipping a 17mm open ender over the nut between the coils.

Undo the nut against the cap. Ill-fated boardshorts (won’t be needing THEM in Melbourne!) acted as padding during reassembly. There’s very little preload on the stock springs so don’t expect any homicidal jack-in-the-box violence; it was all over by the time the cap was wound off.

10. Remove the cap, the steel collar and the old spring (dripping oil…) and slip the fork leg to an angle so the cable tie loosens and the leg can be slid free. I got all sorts of conflicting info on oil volumes so I measured the level with a vernier calliper. Nothing fancy, I just extended it 5mm at a time and swung it around inside until I could see it breaking the surface: 115mm.

11. Pour the worst of the oil out (I measured that too: 490ml) then attach the clothes-peg to the shaft just under the nut.

This way, you can hang the fork leg upside down without the whole assembly over-extending.

12. If a picture’s worth a thousand words, four of them are: “my girlfriend wasn’t home”.

13. I drained each one for a couple of hours. I didn’t flush the fork with fresh oil but this would be the time…

Intermission:
WHAT? The new spring’s 20mm shorter? When I looked it up the listings ended for the KLX250R at 1996 so I went with that part; I asked the retailer to check with the distributor but still felt a little uneasy. I checked the KLX300 listing for 2004 and the same part number appeared. Good enough for me.

14. I tipped in 490ml of fresh oil (BelRay) and measured it with the vernier; near as ‘dammit’ is to swearing.

15. I haven’t mentioned cleaning as we all know what it’s about, but I did get real particular about the thread on the top of the shaft and where it mates with the cap.

16. The fork leg went back into ‘wheelie bin clamp’ (or RaceTech part number TMSV01 if it’s bin day) and I tie wired through the axle hole to the bin handle to collapse the fork

16. Pull up the shaft and in with the spring. The shaft will slide back down but if you get the clothes-peg between the coils and onto the shaft under the nut, you can wind the spring down (pulling the shaft up) in a dodgy rack and pinion pantomime until the thread’s high enough to get the cap on.

17. A spot of Loctite went onto the cap inner thread (to bond with the shaft) then I balanced the collar on the cap with the two preload washers in place then wound it onto the shaft. My torque wrench is back in WA so I trusted feel and loctite) to tighten the nut against the cap. A bit more caution and a rag when poking the spanner between the new coils…

18. Off with the clothespeg and a spot of fork oil on the o-ring around the cap before doing it up.

19. Reverse the disassembly stuff and either PUMP YOUR FRONT BRAKE BEFORE THE TEST RIDE or call an ambulance before you set off.

In honour of the man from KLXZone:
“The job’s a fish!”

[Mick DMember]

OH, I was wondering how the wheelie bin was gunna fit into the scheme of things.
Great post!! That is gunna help a ton of back shed mechanics. :woohoo:

[ChrisMember]

Hey Nuro,

Thanks for the write up and the pics, makes it a lot easier for when I do mine…

Cheers
Chris.

[Mark FalveyMember]

I’m back after a seriously weird couple of months. Have missed the OB site! Anyway, a ride report on the springs…

I took the bike out to Bunyip and tried the Blue Range loop. Even on the road, it was obvious the front sat higher and was stiffer. I should add that I only started trailriding about five years ago and won’t be worrying any of the front-runners; The Knighter might be more discerning if he can sleep his way to a ride with “Team KLX”.

The extra ride hide was had the usual pluses and minuses. The ground out there is like concrete and the ruts/washaways are cartoon deep (think Roadrunner.. anvil..) despite the extra height I still scraped the sidestand in some ruts (pegs pushed back, feet up near the rads). Standard springs and a rider weight over my meagre 70kg would have grated your plums over the filler cap. Minuses? Short leg on the long side as a friend would say, but 30mm vertical is worth ‘enough’ diagonal, sometimes. Worth the entry price alone?

Now for the stiffness. Before the transplant it felt a bit better at the front than my old XT225; yes – whoopee. It did not inspire confidence! Downhills that had my spasming fundament ripping stars out of the rear guard DID NOT compress the front end to the slinky spring nausea of the standard items. The result was a lack of lurching in the trials bike situations that only has you working that much harder when the bars are way too far in front of the axle. Sadly there wasn’t much single trail or sand to check out the difference. But I reckon it’s money in the bank.

The rear spring was only a fly-sht too stiff for my weight, so no poor match for front and the combo made me happy. I’ll do something about the MXRetreads soon…

[ChrisMember]

Hey Nuro good to have you back, always good to have fellow KLXers around. We spent a weekend at Louee and some time on the MX track, certainly became obvious very quickly how week the front stock springs are.. I’ve heard they build these for a 75kgs rider that might be O.K in japan but not for the westerners. I’m tossing up wether to go heavier springs or to try the preload / heavier oil path first.. So out of 1-10 how much better do you think the heavier springs are and If you don’t mind telling everyone on this site how much do you weigh??

Cheers
Chris.

[Anonymous]

I’d be interested to hear this as I am thinking about sorting this on my bike. Not a green machine but the principles should be the same

[Mark FalveyMember]

1-10? It’d have to be a very solid 8. Losing the airbox lid, tampering with the muffler and getting it dyno’d would be a 5 by comparison. Sometimes you just aren’t going to wind it on because you know the custard front end will tip you off! I had to think hard to separate the big plus of the springs from the monster grip of the new MXRetreads but I’d stick with 8/10.

In amongst all the rest of the physical disintegration, weight isn’t something I’m touchy about! I’m about 70kg (fine for the standard rear spring) but if I remember correctly, the standard front is spot on for a 40kg rider.

http://www.racetech.com/evalving/menu/searchdirt.asp This link will help you see what spring weight you’ve got in the bike now and what you should have. They cover most bikes you can think of.

I was tempted to try a cheaper option like oil until I saw what a joke the standard springs were. I think TB mentioned realy soft springs for the Finke and top shelf valving, but that was the next step up and I didn’t feel I could justify that kind of expense or time without the bike. Good luck with the decision making!

[Mark FalveyMember]

Off-subject Chris, but I can’t pick out your post about the headlight brackets (the Acerbis has been in the plastic bag for months!) The clocks are heavy, BUT they work, bore the coppers and cost nothing to keep! Buggered if I could bend stainless with anything I could bodge up in the kitchen but I reckon I could sort something in 2mm aluminium. Just want to check for ‘gotchas’ before I wade in!

[DeanMember]

Team Nurofen wrote:

Quote:

I had to think hard to separate the big plus of the springs from the monster grip of the new MXRetreads but I’d stick with 8/10.

Gyday Nuro,great to see you rate the MXretreads highly;)

cheers Ollie

[Anonymous]

Sorting my suspension will be the next mod I do to my bike. This weekend will likely be my last ride of the bike until the Christmas party though, so it will probably be next year that it gets sorted

Great write up Nuro

[Mark FalveyMember]

I’ll write up the MXR’s soon!

There are more complicated USD forks out there, but if an amateur like me can do the job without a shed, there’s satisfaction and better riding to be had without major expense!

[Anonymous]

I had a bit of a play with my rebound clickers at the weekend and cannot believe how much difference a few clicks made. Totally sold on getting my suspension set-up properly now

[Author]

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