KLX250/300 – fitting new fork springs

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!”