Decompression lever stuck?

Hey guys,

Long time lurker, first time poster.

I have a 04 YZ450F and upon my last ride this past fall, I go to start it one last time and I grab the decompression lever and its stuck? We were riding on a fairly muddy trail system all day and I just figured it had some gravel in the lever hinge area. After a thorough pressure wash it appears to be still stuck and I cannot depress the lever at all?

Any ideas?

Been riding for many years, but pretty green to the 4 stroke world.

Thanks for any help or suggestions.

~I accidently posted this in the WR forum.

Well, we will need more information. A 04 YZ450 did not have a decompression lever. It had auto-decompresssion via the exhaust cam. Please confirm year/model of your bike.

I think he meant the hot start lever.

By hand, disconnect it from the carb and pull the plunger out. Confirm the cable moves smoothly. If not.lean and lube the cable, disassemble the lever and clean. If the lever and cable is OK, the plunger is gunked up. Use contact cleaner, clean the plunger and carefully clean inside the plunger bore on the carb (use Q-Tips.)


I bought the bike used and it has a after market lever right next to the clutch lever (just under the kill switch). I assumed that this is what it was.

Is this the "hot start" lever?

Trace the cable. If it goes to the carb, it is a hot start, if it goes to the head, it is a ceomp.

It's a hot start. No YZ450 ever had a decomp cable. Pull the tank and pull the plunger out of the carb as instructed above.

Thanks guys,

Looks like I got something to do this weekend afterall!

Minnesota forecast for this weekend looks like a high on Saturday of -3 degrees.:cool:

Use caution when threading the hot start nut back on the is a cheesy nylon nut and it strips out very easily. You can order an aluminum one from Zip Ty racing.

I put a very light coat of grease on my hot start plunger when I reassemble it to help keep it lubed.

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