Engine rattle

[popeye]

So my machine is a 2019x. 3600 ish miles. Over the last few hundred miles, when in a higher gear lugging out the engine at a lower rpm, as the load on the engine increases I can hear some ticking, it’s rpm engine based, if I down shift and bring up the rpm’s the noise lessens almost to the point where it goes away, or is drowned out by the increase in engine noise. Also at the same time this all started happening the machine got harder and harder to start when cold. It wouldn’t want to idle, and more so than just the usual rough idle fuel injection relearn with major elevation change. I pulled the valve cover off thinking the valves needed adjustment, and they all were with the factory service manual spec of .006 for the intake and .009 plus or minus .001 i notices the cam shaft decompressors on the exhaust side of the cam were pretty loose. I found in the service manual these pics, that they are supposed to be spring loaded


But the one on the #2 cylinder doesn’t return like the book says it should.

Here’s a video

January 11, 2022

youtube.com

The dealership I just dropped it off at was shown the video and said “oh that’s normal”, but one of the first things the service writer told me is they haven’t had to open up many talon motors, or have even seen many come through the shop. They are mostly a street bike dealer….
What does everyone here think

 

[Admin]

 

[Adam490]

@snuffnwhisky

 

[HondaTech]

I've had a look at a couple Talon valvetrains here recently and they do seem looser than others that ive felt.

Edit: Your video seems about the same as what ive come across.

 

[NTCPrezJB]

I don’t have any advice but best of luck with it

 

[SLOWPOKE693]

The stock cam I took out of my engine does that to. Must be normal, my engine only has 640 miles on it.


Is the winter blend fuel making it ping?

 

[popeye]

It started doing it in the Oregon dunes last August, slowly getting worse and loader. So I don’t think it could be the fuel. While in Oregon I was using ethanol free premium. It not my normal fuel. At first I wondered if it was just me hearing things. I put it’s second set of plugs in it last September, and they didn’t change anything. The dealership told me it’s just the noise of the transmission and some of the loose plastics that have seen a little bit of damage… so I’ll be going to the dealership to take their tech for a spin today.

 

[SLOWPOKE693]

I took a good look at my stock cam last night and figured out exactly how that automatic decomp setup works.

On the base side of the exhaust lobe, behind the decompression lobe, drilled into the cam is a spring loaded pin that defaults to in when the engine is off. When you crank the engine over to start it the oil pressure of the engine overcomes the spring and pushes it out. This in turn locks the decompression lobe in the out position giving the base of the exhaust lobe slight valve lift that in turn bleeds off some compression for easier starting. Once the engine starts, centrifugal force from the big "counterweight" on the opposite side of the decompression lobe overcomes the force of the oil pressure acting on the pin and the decompression lobe moves out of the path of the exhaust rocker.

Those two parts OP pointed out on the cam as "loose" are perfectly normal and nothing to worry about.

 

[popeye]

Well went to the dealership to take their tech for a drive to show them the engine noise. They heard it and are gonna look into it. I’ll post here with what they find