3 of my valve buckets look the same with a smooth top, the one under the exhaust valve with the ACR has a strange perfect circle in it, it looks more like a manufacturing thing, almost like its ground into it on purpose, its below flush. I dont see any abnormal looking wear on the cam lobe, but it seems odd this one bucket would be different, what do you think? sorry if the pics show up too big

 

So it is smooth? even lightly dragging a scribe across it? Wish I could scan it on an AFM and really see on the nm scale. See any unusual wear on that cam lobe?

 

the whole lifter is smooth except for that circle which is recessed so im not sure it affects anything.... idont see any unusual wear on the cam but this motor only has 3k on it.

Its just weird, it doesnt look like "wear" it looks like it was machined into it. If no one else has seen a lifter look like this then im probably gonna spend the $33 and get a new one, problem is there are so few pics of all the lifters so i can determine if its normal or not.

Thanks

 

Mine didn't look like that after 7K miles.

 

From what I observe in the photos, that ring should not be there. In my opinion it looks like the KACR has had a shoe hang up and dig in. Because the shoe is offset it would cause a circular rotation making the round groove as it hits and wears. They were not designed for continual contact nor do they have the surface finish to do so as the actual cam lobe does. This is my best root analysis without actually seeing the cam in place and seeing the actual bike in person. If it is in line with the KACR shoe contact this is probably a fairly sound observation.

In this case if it is the shoe causing the groove I definitely recommend you either entirely remove the KACR system from the cam (press it out) or look in the MCM document in my signature to lock the KACR in the disengaged position (using mild steel wire) to keep the shoe from hitting the cup and dragging. As much as some do not like my method it is totally sound from a mechanical engineering standpoint -aka it fulfills the task using adequate quality material for stress and strain. I actually do have the degree to back that up.

Let us know if the shoes hit where the groove is or what is coming into contact there.

 

Yes you are right klx678, i actually discovered what it was this morning but hadnt had time to post yet. All it took was putting the cam back and looking what was near that circular gouge...

There is a small "bur" or nick on the very edge of my KACR shoe, that bur perfectly matches up to where that circle is. I believe it has been digging in every time i start the bike and slowly spinning the tappet in place, creating the "lathed" appearance to the groove which is why it looks so perfect.

You can see the bur and the groove a bit better. Not sure what I want to do to fix it, going to order a new tappet today. I can either grind that bur flush or slightly below flush, or completely disable the KACR. I am leaning towards both actually...

 

I'd grind it then lock it in place if you don't press the whole thing out of the cam. It can be pounded out if you can hold the cam so it doesn't damage the cam surface. Some here have done that.

The lock out wire dimensions are in the file if you go that way.

I would not do the spring off shoes loose though to make sure it doesn't dig in again.

Makes me wonder if the clearance to the shoe is so close that burr hit all along. The action of the valves makes them rotate a bit causing the groove in a circle. I don't know if it is caused by the spring action, although that's what I would guess. I just know if they didn't do so there would eventually be a wear pattern from the cam hitting the same spot every time and that doesn't happen, although they may eventually dish over time.

 

I wanted to completely press it off the cam (i have a hydraulic press) but I am very worried about not being able to hold the cam without damaging/bending it.

I was debating just grinding the head off of the pin that the KACR pivots on, that should allow me to remove all the moving parts, but will leave the flat welded on part. Not sure if that would cause any balance/harmonics issues but it would certainly stop the KACR from working...

 

Why are folks against having a working KACR?

Ride on
Brewster

 

Because mine nuked a valve tappet in under 3k miles, and MAY have nuked my cam in the process.., that alone is enough frustration for me to completely remove mine. add in multiple reports of KACRs failing on KLRs and KLXs and whiping out entire motors.... if it's not really needed then that's even more of a reason to remove a potential failure mode. I can see why people would want to leave it alone, but after having mine fail it's an easy choice, glad I caught it before it destroyed my whole motor.

Absolutely nothing about the KACRs construction is confidence inspiring that it will stay together long term. I in no way advocate people remove it for no reason, but for me... It was the easy choice

Btw I was unable to press mine off without making a custom clamp, so I cut off the pin that holds the moving parts in place, just the process of cutting off that pin cracked a "wing" of the KACR and I had to remove it entirely, again not at all confidence inspiring... If I could press the whole thing off I would