2005 yfz450 wouldn't start - Yamaha YFZ450 Forum : YFZ450, YFZ450R, YFZ450X Forums

Spoolin250 · 11-18-2011, 11:33 AM

it won't start, i adjusted the valves exactly like the valve adjustment thread on here, had 90psi compression when i started, i put smaller shims in due to the intake valve clearance was only .002. i now have them all at .006 and the compression is down to 60psi now. i loosened the chain tensioner when i did this but never lost place of the chain. while doing the compression check i noticed that the engine seemed like it was dragging, felt the timing chain and it was hot like it had been running, it had only been spun over maybe 15 times during the compression check and never fired, is there something wrong with the tensioner, seems like the chain is much tighter now.

Spoolin250 · 11-20-2011, 01:25 PM

ok, that issue is fixed, now i notice i have no fire/spark. anyone have a wiring diagram for the ignition system and voltage values at points involving the ignition so i can try and narrow down the issue.

Spoolin250 · 01-23-2012, 10:28 PM

Fixed! well mine is fixed, the CDI unit was toast. replaced it with a Dynatek cdi and its good to go.

11-18-2011, 11:33 AM	#1 (permalink)
Spoolin250 Member Join Date: Oct 2011 Posts: 35	2005 yfz450 wouldn't start it won't start, i adjusted the valves exactly like the valve adjustment thread on here, had 90psi compression when i started, i put smaller shims in due to the intake valve clearance was only .002. i now have them all at .006 and the compression is down to 60psi now. i loosened the chain tensioner when i did this but never lost place of the chain. while doing the compression check i noticed that the engine seemed like it was dragging, felt the timing chain and it was hot like it had been running, it had only been spun over maybe 15 times during the compression check and never fired, is there something wrong with the tensioner, seems like the chain is much tighter now.

11-20-2011, 01:25 PM	#2 (permalink)
Spoolin250 Member Join Date: Oct 2011 Posts: 35	ok, that issue is fixed, now i notice i have no fire/spark. anyone have a wiring diagram for the ignition system and voltage values at points involving the ignition so i can try and narrow down the issue.

01-23-2012, 10:28 PM	#3 (permalink)
Spoolin250 Member Join Date: Oct 2011 Posts: 35	Fixed! well mine is fixed, the CDI unit was toast. replaced it with a Dynatek cdi and its good to go.

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