decompression cable

[bigbrummer]

Hi all
Just serviced the bike (55w) and found the decompression cable needs replacing. At the kickstart end, is it just a case of removing the small cover and replacing the cable, or is it more complicated? Do I need to drain the oil for instance. Also when I line up the T mark on the flywheel with the timing mark to find TDC, there is no free play in the rockers at all. When all four rockers have freeplay in them, no marks line up at all. The bike however, runs perfectly. What can this mean?
Thanks Dave

[nate]

Hey Bigbrummer,
If you get the "t" mark lined up with the pointer and there is no clearance at all, turn the flywheel another 360 degrees so the marks line up again and there should be some clearance. Sorry I can't help with the cable, mine is electric start only.
Good luck,
Nate

[oldbaldrick]

Hi,
Replacing your decompressor cable is very easy and should only take about 5 minutes.
Slacken off the adjuster at the top and pull the small lever up (against the valve spring pressure) to release the top part of the cable. Remove the small cover by the kickstart and release the bottom of the cable. Fit the new cable starting at the bottom and then fit at the top. Use the adjuster to provide a few mm of slack in the cable. Job done.

[muro]

Just did this on my 55W with an experienced mate looking over my shoulder.
Put the new cable in (It's pretty obvious how it fits - I found it easier to put the bottom end in first).
To adjust - undo the right hand exhaust valve cover. Turn the engine over with the kick start until you find the point at which you can wiggle the rocker. You now know that the exhaust valve is closed. Adjust the cable so that there are a few mms (say 5mm) of play before it goes tight. Turn the engine over a few times with the kick start (should be easy now). Close the cover - job done. With the adjustment, you are just making sure that the valve is not being held open by the decompression cable hense if the valve is closed and there is a few mms of play in the cable you know that the cable is not holding the valve open. Note: you should check the adjustment of the cable every time you adjust the rockers.
Hope this helps
Muro

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[Matt595]

Just take a 19 key, turn crank unclockwise until you see the "IT" sign thru hole.
Make sure decompressor has a play, otherwise turn crank one more round.
When you feel the very small play, take off cable.
Grease new cable with motor oil, put on place, make sure the play when tightened is not less than 1.5mm and not more than 2.5mm.
Not enough play = you'll burn your valve
To much play = decompression won't work properly.
With brand new cable, best play is 1.5mm
Check several times again when installed, by turning crank to IT several times, to see that the play remains the same.
Sure, decopression cable is easy to change but it can cause serious damage if not well done.

Matt

[bigbrummer]

Thanks for your replies. Hopefully now I won't almost break my leg every time I kick it over.
Dave