20 Most Recent 2004 Yamaha YZ 450 F Questions & Answers

I had the same problem on my 2003 Kodiak. It ended up being the CDI Box. The Warn Winch was the cause. I had to replace the CDI Box on my twice before figuring out it had to do with the winch since it happened only after using it. I used the winch before when new and never had a problem.

The 2003 Yamaha YZ450F is a big-bore, air-cooled two-stroke motorcycle. It was first introduced in 2001 and was the replacement for the 2000 model year YZ450F. The engine displacement has remained at 450cc since then. It uses an overhead camshaft with four valves per cylinder and a 4 valve/cylinder head configuration to create power output of 35 PS (29 kW) @ 8500 rpm and 25 lb·ft (35 Nm) @ 7200 rpm with a compression ratio of 9.7:1.

Take compressed air and blow air up into the the weep hole. For some odd reason it made 3 different CRF's stop leaking. It's worth a shot.

10 N-M or 7.2 Ft/Lbs. Just a little more than "snug".

the weep hole was designed to let you know that the water pump is damaged ,shot, kaput the following links are more technical COMMON WATER PUMP FAILURES THEIR CAUSES FlowKooler Hi Flow Water Pumps Why Is There Small Hole in Water Pump eHow