Repair & Maintenance

400ex heavier timing chain?

Ive heard of upgrades for a timing chain for a 400ex, like from a crf450r or something. Anyone know what I should order so that my timing chain doesnt slip off cam again due to so much slack?

Also anyone had luck with the manual tensioners? looking into fixing this so that it doesnt happen again. Thanks!!

Also, I pulled head, and two valves are slightly open, shouldnt they be closed if i pulled rocker arm head off and then the piece that holds the valves and cam etc? because no pressure is down on the springs?

Repair & Maintenance

400ex heavier timing chain?

Ive heard of upgrades for a timing chain for a 400ex, like from a crf450r or something. Anyone know what I should order so that my timing chain doesnt slip off cam again due to so much slack?

Also anyone had luck with the manual tensioners? looking into fixing this so that it doesnt happen again. Thanks!!

Also, I pulled head, and two valves are slightly open, shouldnt they be closed if i pulled rocker arm head off and then the piece that holds the valves and cam etc? because no pressure is down on the springs?