Anyone heard of timing chain issues on the 2015 450?

That sounds like the issues that people are having here. Kickstarting leads to locked piston; valve timing is so out that the engine is damaged.

Might an aftermarket tensioner help? Does someone make a better quality cam chain than stock?

I am still keen on the 2016 model, but might keep an eye on this.

Hi I have just done a top end rebuild on my 2015 yz450f. After putting it back together it jumped out of time. The intake cam was 3 teeth out and I know the engine was definitely in time when I first put it back together. I checked the piston and valves and luckily no damage was done. I'm just having a lot of trouble understanding why this has happened. Has anyone had the same thing happen or maybe know the cause?

The tensioner is not at fault, and all of the "aftermarket" chains I've seen are the same Japanese Borg-Warner that the OEM is, if they are that good.

 

The Gen3 and 4 engines don't appear to have any more trouble with cam chains than either of the earlier 450's or the 400/426 did.

 

The biggest problem I see with them is that the chain stiffens up, sop that the links don't pivot freely, which leads to a condition that can cause the chain tensioner to allow the chain to skip if the engine kicks back or rebounds off of compression as it stops.  I'm pretty certain it's an oil related issue, and it's more common on bikes that sit for extended periods of time. 

In my 08 yz450. I change the cam chain every 25 hours. Its cheap and easy to do. Cam chains are less than 20 bucks. Gaskets are a few bucks. They stiffen up quick in 30 hours.

In my 08 yz450. I change the cam chain every 25 hours. Its cheap and easy to do. Cam chains are less than 20 bucks. Gaskets are a few bucks. They stiffen up quick in 30 hours.

Waste of money...

Put 200+hrs on my 15 YZ450F, never touch the timing chain. Actually never touched the motor except for a slight valve shim...

Waste of money till one causes the cams to lock before a triple. Happened to me. Luckily in mid air i always pull in the clutch. Second sooner i would of been hurting. After 30 hours you will see some links stiffen up. I would rather spend on pm stuff then bling.

Waste of money till one causes the cams to lock before a triple. Happened to me. Luckily in mid air i always pull in the clutch. Second sooner i would of been hurting. After 30 hours you will see some links stiffen up. I would rather spend on pm stuff then bling.

So because something happens to you, it's going to happen to everyone? You either got unlucky or your maintenance program is questionable. I can record 100s of hours over multiple bikes without touching the motors. The last 5 4ts I've owned have never have never had the motors opened with a 1000hrs between them. I guess Rotella, good fuel and clean air filters really aren't the answer

20 to 25 on cam chains, 75 on pistons, 150 on head and crank. If i was trail riding then maybe double everything. Supercross and mx tracks i keep to a strict pm schedule. Also i spot weld the cam gears. 200 hours between major work. Thats frightening to me.

20 to 25 on cam chains, 75 on pistons, 150 on head and crank. If i was trail riding then maybe double everything. Supercross and mx tracks i keep to a strict pm schedule. Also i spot weld the cam gears. 200 hours between major work. Thats frightening to me.

I'm sure to some 200hrs is, to others not so. I personally have never had a 4t motor lock up on me in a frightening moment, so at this point I don't see the relevance. But if that day comes, I'll guarantee I will be more dillegent. Also, depends I then motor too. I talk in terms of 450/500 4ts, not a 150R/250F which would see considerably more time in the upper RPMs...

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