I have a 2000 yamaha ttr90. When tring to kick start it. It sometimes will have full compression and starts right up. Other times it will kick over and have no compression. It feels like im not getting any thing. I took off the side cover and checked to see if every thing is turning when it is being kicked over and it is just no compression. If i push in on the clutch pack a little it gets full compression and will start. Other times it will not and the clutch basket will turn but the clutch packstays still and i have no compression. what could be going wrong?

I had the same issue with my 2005 TTR90. The friction plates were glazed. Check the friction plates. If the are black and glazed, they should be replaced. For a quick test, rub the friction plates gently with sand paper to rough it up a bit. If you put it together and it works, then you have the same problem as I did. Note that, this is not a fix, you do have to replace the friction plates.

Does it feel like your kickstarter is slipping perhaps?

Check the spline teeth on the kick start pedal.

It's possible it's the shaft that slipping and not that you're not getting compression, since that would normally be constant, or not. I don't think you have a compression release but it's possible. I had the TTR250 (and loved it). Check on the top of the cylinder and see if you see a small cable being moved. I've usually only seen this on larger CC models, and not the smaller units like a 90, but worth checking.

If your kickstarter pedal is slipping then you may just need to tighten it, if it hasn't slipped/shaved off too much of the splines. If it's the shaft that's slipping that's going to be a bigger job replacing.

Good luck!!

:o)