I have an ~1986 Yamaha Ag 200 and I've been pulling it apart as a bit of a hobby to understand a bit more about how it works and hopefully in the end get it going.

I've opened it up so some gears are visible but in order to get even further into it I will have to undo some or all of these gears.

This is wear I'm stuck because the nuts seem to be impossible to crack and when I apply force all the other gears start moving and there is nothing pushing back towards me.

Is there a little trick or something I can use to undo these nuts?

  • 1
    Have you tried loosening the nuts while the gear is engaged with the transmission?
    – Rory Alsop
    Oct 5, 2013 at 7:51
  • Yeah but these gears are coming straight from the crankshaft so it doesn't effect it unfortunately.
    – 202
    Oct 5, 2013 at 12:05
  • Can you take a picture of exactly which gears you mean.
    – Rory Alsop
    Oct 5, 2013 at 13:19

2 Answers 2


I highly recommend that you find yourself a shop manual for the bike. These are available in hard copy version, and sometimes in PDF format as well. It will make it clear how to perform various operations, and make it less likely that you will do it wrong.

I highly recommend that you do not mess with any of the gears. Transmissions run at very tight tolerances and it takes skill to put the back together and have them work well.


I had to look it up as I've never heard of an AG200 but I know what TW125/200 is If your looking under the right side engine cover, lock the clutch and primary drive gear with a penny between teeth, it's easier than trying to use the special tool you need but don't have Make sure you don't use the oil pump drive gear as it is too small for the load and will crack or shatter

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