Valves

[motocop729]

At what time is everyone getting their valves check. Approx. How many hours on the bike. I have a kx 450

also any recommendations on who to use. I am not by anymeans four stroke savy.

[supermotofarm34]

At what time is everyone getting their valves check. Approx. How many hours on the bike. I have a kx 450

also any recommendations on who to use. I am not by anymeans four stroke savy.

ride it till it wont start then put valves,retainers an springs. jmo

[Junk]

Your supposed to check them?

[jmtracing]

I always did 10-20 hrs along with Top Ends.

[Uncle Boogie]

We usually go 30 hours on our Yamaha 250f's. Then we replace all valves and topend. We only check them prior to that if they're hard to start.

[MX154]

Your supposed to check them?

+1

[ktm300hater]

it should say in your owners manual, but I check mine evry 20 hrs or so. Just some FYI, our 08 kx 450 has 200 hrs on it and the valves have never moved..but our 09 dropped a valve at about 25 hrs...

[PU300]

If it starts popping... can be a sign that the valves are tightening a little. Generally it hasn't been an issue for the 450 unless you are a 16 yr old 450 novice/inermediate riders that over revs the crap out of the bike.

If you change the air filter and oil/oilfilter regularly you should be able to get at least 30 hrs out of a top end and probably won't need a valve adjustment during that time.

It us super easy to check the clearance though just to keep your mind at ease.

Tank off

Valve Cover off

Top dead Center (cam lobes shhould be pointing up and away from each other at a 45)

Intake- Slide a .004 feeler guage between the bottom of the cam(bottom) and the bucket(Top)

Exhaust- Slide a .006 feeler guage through on each the same way as intake.

This is the tighter end of the wear tollerence. Basically until the feeler guages won't go through the gaps then you don't have anything to worry about.

Once it doesn't go through then it's time to shim.

[mxobserver]

it should say in your owners manual, but I check mine evry 20 hrs or so. Just some FYI, our 08 kx 450 has 200 hrs on it and the valves have never moved..but our 09 dropped a valve at about 25 hrs...Mxobserver wonders why it dropped that valve? He further wonders were the retainers in right? Mxobserver also wonders if the valves had been removed recently for any type of work? jus askn!

[motocop729]

Thanks i only have 5.7 hours on the bike. I change the air filter every time and have change the oil three times and the filter one at the initial break in at . 7 hours. I am going to change the oil again at 6.7 with the filter.

[mx4life]

its probably a good idea to pull filter screen out of oil pump on flywheel side and clean it, as it usually has a long peice of gasketsealer from inside the cases on it restricting oil flow. it sucks but you have to pull flywheel off this year to get to it.