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Fork Maint. and other stuff

Discussion in 'Technical and Troubleshooting Torque' at netrider.net.au started by Jimboss, Sep 13, 2006.

  1. Hi I have a couple of question that Im hoping somebody can help me with.

    First of all I want to do an oil change on my front forks of my Honda XL250 Degree. The forks are Telescopic and the the work shop manual says the oil level is 121mm and a 10w oil (Capacity 385CC -dont know what that means). At the bottom of each fork there is an oil drain screw.

    This is the first time I am changing the oil so I was wondering what the process is? This is what I was going to do -please correct if I am wrong or any other opinions welcomed.

    1. Unscrew the drain screw.
    2. Drain oil into container and measure to see if any has leaked.
    3. Re-screw drain screw.
    3. Unscrew the Fork Cap Bolt up at the top near the handlebars.
    4. Pour in 121mm of 10w fork oil.
    5. Re-screw Fork Cap Bolt
    6. Job finished?

    Does that sound right? Should I expect any problems like a spring popping out and hitting me in the face? Can I clean forks when oil drained with an air compressor?

    Also I wanted to know if it is worth doing a valve clearance on the bike - (nothing wrong at moment) or leave until a problem like low/hgh compression arises? Where can I purchase a cheap compression tester(Victoria)?

    Thanks fellow Netriders.
  2. C'mon Im sure someones done a fork service b4 :LOL: -

    Ive worked out that 121mm is the air gap and to pour 385ml in each fork, and to hoist the front of the bike to take pressure of the springs so the they dont wack me in the face. And to pump the suspension up and down b4 taking the drain screw off to help move the sludge.

    And ive also been told to help get rid off the old oil buy buying more fork oil and pouring it in till it runs clear of the old oil.

    Any futher tips - does the above sound right :?:

    Now, with the valve clearance does anybody know of a good instructional site where i can get some info? and where to buy a cheap tester
  3. Nope - you've pretty much nailed the fork thing I reckon. If you ensure the correct amount goes in - and there are no leaks down the track - then you can be sure the amount you have in there is right. What I do is use an old coat hanger bent into a straight bit of wire, measure after each one is filled up correctly, mark the wire and use that as my guide should I need to check the levels (very rare) later on.

    Springs shouldn't be an issue if you undo the bolts slowly and the front is hoisted a little - it's never happened to me, anyway...

    Cheap tester? Anywhere like Super Sheap Auto, Repco, Autobarn....

    Are your valves noisy? Do you have to adjust them hot/warm or cold? Engine smoking?
  4. Jim

    You've pretty much got to take the forks off to do it properly, because once the cap and drain screw are out, you need to pump firstly the fork leg about 15 times, and then using pliers, pump the damper rod about 10 times as the oil drains. You might as well take the springs out and clean them of the old oil while you're at it.

    When you unscrew the fork cap, it'll pop up a bit from the fork tube. You've then got to get another spanner in underneath to unscrew the damper rod from the fork cap. shouldn't be too hard. Then the spacers and springs will come out easily.

    I think the extra fork oil to flush the shit out is a great idea, wish I'd thought of it.

    And yes I was gonna pull you up on the 121mm thing but you've sorted it out - I found an easy way to do it was to mark a dipstick with two points 121mm apart, then put it down the fork such that the top mark was level with the top of the fork tube fully extended. You can then see how close the oil level is to the bottom mark and adjust accordingly.

    Have fun, it's interesting seeing how the forks work.
  5. Hi there & thanks for the replies:

    The valves arent noisey but i thought I would do some preventative maintenance (or in my case stuff it up - Ive never done it b4 and fork out $)

    Manual tells me that the valve clearnance (cold) is:
    IN 0.20 - 0.26mm
    EX 0.20- 0.26mm

    I wanted to know - if I do a compression test and the PSI is at a good pressure - does that mean all my engine parts eg lifters, piston are in good nick?

    Apologies if my questions are a bit lame ass - Motorbike servicing/mechanics is new to me - but am having a ball learning -Great learning curve.
  6. I don't think there'd be damper rods on this bike, so for simplicity I would be doing it in the bike.

    Do one leg at a time, because if you pull both caps off the bike will be on the floor.

    Otherwise you've got it. Undo plug. Pump. replace plug. Remove cap. Put in standard volume. Replace cap.

    Replacing the cap can be tricky, because you need to compress the spring, but on standard springs it shouldn't be that hard.
  7. Thats correct iblast the manual says theres is no damper rods so yeah for the first time i will do it while forks on bike
  8. to set your valve clearances, slip the correct feeler gauge under the corresponding tappet. then turn the fly wheel to top dead center. then tighten up the tappet and lock nut.
  9. Thanks N.A.M can u buy a feeler guage at SuperCheap Auto etc,?
  10. i've got one if you want to borrow it. it looks like a pocket knife but has heaps of thin blades that open up like a fan. each has its thickness marked on it.
  11. The tappets shouldn't be tight-tight. You should still be able to move the feeller gauge, but it should be stiff.

    Always ere on the side of loose, rather then tight. Better they be noisy, rather then burn out a valve.

    On your bike you just need to go to the TDC where both tappets are loose. This is the TDC on the firing stroke. 360 degrees away is TDC on the exhaust stroke.
  12. Hi N.A.M thanks for the offer - much appreciated - I just rang my cousin who is in car mechanic and set he has all the tools and should be pretty straight forward.

    Iblast whats the TDC?
  13. Top Dead Centre.

    The point where the cyclinder is exactly at the top of it's stroke.

    You see reference to TDC when it comes to valve and ignition timing. e.g. static igntion 4 degrees BTDC Before Top Dead Centre.

    You also see things like, Exhaust valve closes 20 degrees ABDC.

    I'll let you work it out.
  14. Thanks Iblast

    Now for my fork service update:

    I took the bike for a spin and work the front suspension too get the oil thinned and too work any to hopefully move any sludge. All good so far....

    Then I remove my fork drain plug, great, a little bit of oil trickles out, so I think too myself -shit there isnt much oil in there - it must have leaked out -so I put pressure on my front - rock it up and down - and then oil, texas tea all over my lucky tracksuit -shit

    So theres a tip for anybody doing there forks - I will fill you in with the rest of my progress once i get some overalls on :).
  15. Completed the fork oil change - it needed it - It was much easier than I thought - I didnt think it would make an obvious difference on the ride, but was I wrong, the bikes front end feels so much better and responsive.

    Highly recommend doing it yourself - I was quoted $120 at a garage for the same job (which I will keep anonymous) and it cost me $16 for the 1lt of Shell Fork oil. Very Happy so is my wallet.

    Thanks guys for the advice.
  16. ...and how much for dry cleaning or new tracksuit :D Squirts like buggery if you do that eh!
  17. No, Im not going to wash it - its become a rag for wiping up future oil stains :)
  18. On a similar subject, the GF's CB250RR is leaking oil from the right fork, and she reckons there is a "wobble" or "judder". Anyone know how to fix an oil leak on these?

    Any replies appreciated.