RM-Z450 06 RMZ450 doesn’t want to start

I picked up a 06 rmz450 and he told me he tried to do the carb rebuild kit on it and tested it and didn’t get it running so posted for sell. when I got the bike it had spark but low coolant so i just did coolant, oil and oil filter change and new spark plug. took carb off and heard sun shaking inside and opened it and found 2 screws in the float bowl not even in place. put them in place, didn’t have carb cleaner atm so just sprayed with compressed air, cleaned jets, put it back together hoping that was fix but only got to get it running with choke. turning on wasn’t a big struggle but it would shut off when i turn choke off, would also backfire and pop a lot when revving it. so took off carb again with carb cleaner this time cleaned all jets again, the circuits and all passages, put the carb back on and now it doesn’t start at all. was hoping this bike would be a quick fix and ready to rip, but now i don’t know what to do. any reply would be appreciated.
Have you checked the valve clearance?
-BIG DAN:thumb:
i will be honest that was the exact thing i had in mind! i didn’t check valve clearances because i don’t know how to. it will be 175 including the shims to take to a local mechanic that will do it. I had a feeling it was that too but the question i was asking myself is, is it really my valves ? would it have not started at all in the first place if it was my valves? or it would still start but run poorly like it was? how come it was fine starting before i cleaned the carb correctly but after, doesn’t start at all?


Staff member
Checking valves is pretty easy and only requires a few tools. There are certainly a few videos on YT to walk you through it.
Valves being out of adjustment can cause all sorts of weird symptoms.
Hard starting, Hard starting when hot, only starts when bumped, backfire, weird idle issues....

I have had a bike start one day and not the next, valve adjustment being the issue.
Unfortunately, once valves start moving or needing adjustment, it's usually the beginning of the end for that valve. It may need shimming again soon. Once out of shim adjustment, valve job is required with new valves and seats.
-BIG DAN:thumb:
On most carb bikes I’ve encountered that will run with the choke on and die when turned off, it’s been a problem with the carb. Usually a good cleaning using acetylene torch tip cleaners to chase the passages and jets fixes the problem. You can pick up a set of cleaners from most auto parts, Harbor Freight, or Northern Tool for around $5. However, it probably would be a good idea to at least check the valves since you don’t know if the previous owner did the regular maintenance.