My YZ426F 2004 won't start! Has less than full compression.... I have been told a couple of things: Valve seals/ shim adjust Bent valve stems Timing/ timing chain HELP!

SOURCE: will there be valve damage from my timing chain.

Should be a non interference motor so no.

Mike Butler

• 6674 Answers
• Posted on Feb 21, 2009

SOURCE: replace valve stem oil seals

Make up an airline fitting that will screw into spark plug hole, or buy from autoparts , or tools supply place. You put compressed air in cylinder while changing, which holds valves in place.

SOURCE: danger of bent valve and difficulty of replacement with broken timing chain

dealing with timing chains its harder then timing belts i mean if you have the right tools it can be done but it can be pretty difficult when dealing with the timing , and the chance of a bent valves it depends if you have a 2.0L DOHC there is definatelly a pretty good chance that u might have valve or piston damage, if you have 2.0 SOHC u wont have damage at all

SOURCE: 1997 nissan pickup 4wd, just had timing chain

Not likely. You have a 4 cyl engine with over head cam. It has hydrolic lifters. If it wasn't making the noise before he replaced the chain, then its something he did...or didn't do. If it was making the noise before, most common reason would be 1 or more lifters not pumping up. If you have a six cyl, no one changed the timing chain, (It doesn't have one!) The 3.0 6cyl has a belt.

SOURCE: How to fix a timing belt and bent valve on a 2004

if the valve is bent the cylinder head has to come off but make sure the valve is bent first because this could run 500 plus to fix