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Motorcycle Valves, Tappets, and Clearances

Discussion in 'Technical and Troubleshooting Torque' at netrider.net.au started by Tomcatalex, Jan 30, 2008.

  1. Motorcycle Valves, Tappets, and Clearances

    How do I gain access to them? Is there an easier way than opening the whole thig appart.

    It says that the gsx range including katanas have a simple valve adjustment, a nut and locknut?

    and is it possible to put the top end of a gsx400 twin on the gsx250, they look like the same fit, would this make the bike a 400cc?
  2. Well you could try the gynecologist's way, and come in through the exhaust pipe!

    But no there is no such thing as a simple valve adjustment, some are easier than others, but all 4stroke bikes/cars/trucks etc etc are the same you must remove the rocker cover to gain access. Then you have to have some knowledge of TDC etc.
  3. 1. Complicated job, you have to take the rocker cover off and expose the innards. Get a workshop manual and follow it precisely, ideally with a friend who knows. You will need some mechanical skills and the book at a minimum.

    2. Probably wouldn't fit, definitely wouldn't make 400cc although you might get to 320ish. It would be a bugger of a job, not worth it really. Just save your time and money and buy a bigger bike.
  4. Valve adjustment is as simple as it gets on the gsx twin. Screw and lock nut. You just need to take the rocker cover off and the timing cover, so you can crank the engine over with a socket and know exactly where you are at.

    The 400 and 250 are very closely related so it may be possible to swap some bits. unless you swapped the crank it wouldn't have the stroke to make it a 400.

    And that would only work if the main journals were all the same. Swapping pistons and barrels would mean the wrist pins had to be the same. Likely, but not guaranteed.

    Also some of the 400/425/450 engines had 2 valve heads instead of the 4 valve of the 250.

    Keep in mind these things have a balance shaft too, so bigger pistons will create a rocking couple.

    so all in all it's too begucking complicated. Do a full engine swap if you want too keep the bike. That is of course if you can find one, which I doubt. But that applies to the cut shut option too.
  5. Edit: made a bobo :oops:
  6. if you got the manual, make sure you got the tools, the manual will list what you need.
  7. I've never done a bike vlave adjustment, but I did many checks on my first car :roll: ... anyway, the engine must be stone cold for best results.

    +1 on having a factory manual or equivalent.
  8. Extra tip, chuck the bike in 5th or 6th for extra mechanical advantage and wind the engine over with the rear wheel when finding TDC.

    Screw and locknut is a piece of piss after your first time with a manual.
  9. This is half the reason Im on my 2nd Bandit12. Screw and locknut valve adjust. Service only have to get carbies balanced so costs me around 150 bananas, instead of the usual 3-4 hundred if I had bucket and shims.
    Heaps of stuff online about adjusting valve clearances. Buy a manual, read heaps, give it a go, ask a mate around who has done this procedure before, as 2 heads always better than 1 with mechanicals you are not familiar with, and give it a go, you will be fine.