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Discussion Starter · #1 ·
So I recently purchased my 2006 KLR with 34,000 miles on it. I have a thread in the introductions section of this forum if you'd like more information. The previous owner didn't know the last time the valve clearances were checked, so recently I decided I should do that and fix the leaky valve cover at the same time

I should state up front while I am no engine expert, I am a fairly experienced mechanic but I am new to motorcycles and KLRs. I have done some light engine work before, and have helped assemble long block car engines as well. However I am no engine builder.

The intake valves were barely in spec so I anticipated ordering shims, the exhaust valves were not in need of adjustment. I removed the camshafts, and I was immediately disappointed at what I saw. Mind you, my phone doesn't take excellent pictures s(I tried to do the best I could).

IMG_20210110_163244.jpg IMG_20210110_163308.jpg IMG_20210110_163315.jpg IMG_20210110_163323.jpg
As soon as I removed the VC, I saw that this piece of metal had been rattling around the top of the cylinder head. It was located on the intake side of the head. Is this a cam end cap? You can see me placing it at the end of the intake cam to visualize if that's where it's supposed to be. Are these cams supposed to fill with oil once under oil pressure? That was my first concern.

However that wasn't the worst thing. The head journals and some of the cam bearing caps looked (to me) awful in places. I've seen cams/valvetrains with many more miles that looked perfect, and clearly there is significant damage to the aluminum bearing surfaces (in varying degrees). Prior to discovering this, the engine seemed to be running well. No burning oil or awful sounds. Now that I know what it is, I think I might have heard the loose piece of metal rattling around the top of the head before I disassembled.
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The original owner (not who I purchased the bike from) installed a 685 kit from Schnitz, and it's safe to assume something went very wrong to motivate buying the big bore kit. When I just finished replacing the clutch recently I found aluminum chunks (big pieces) in the oil screen that I can only assume were once a piston. I decided to read up on KLR engines a bit before starting this thread, so I am very aware if the engines are run low on oil the top end is the first thing to go. I'm thinking the original owner did this, somehow it blew up the piston, and damaged the journal surfaces enough to be bad but less than catastrophic.
 

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Discussion Starter · #2 ·
It gets better, at some point in this KLR's life the KACR system was contacting one of the valve cover thread bosses and slowly ate away at the metal, this is what that looks like.
IMG_20210111_160907.jpg IMG_20210111_161103.jpg

How could the cam even walk that far with the chain tensioner and the chain guide at the top of the cylinder head? I'm baffled how this could happen, and it makes me wonder if that's how the intake cam end cap came off. Here are more journal pictures:
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Regardless of everything else, after reading about the banjo bolt oil mods I'll definitely be doing those soon.

I am thinking the head and caps are toast, as the worst of the visible damage is definitely catching my finger nail as I slide across it. Not all of the damaged areas caught my fingernail but some. In the pictures some of the wear is disguised as a reflection. The cams (I think) are salvageable, because despite obvious wear marks I can't feel any significant grooves. Does anyone think I'm wrong about this judging from the pictures? A friend suggested I try polishing the surfaces, but I have read that polishing only removed 2 ten-thousandths of an inch, and thats significatly less than what my finger nail is catching.

Before typing this out, I premeditated a few directions I could go, but I'm not sure which one makes the most (or any) sense:

1) Since the bike seemed to be running well, order the needed exhaust valve shims, somehow find a cam end cap (HELP!), put the engine back together, and have fun on it WHILE keeping an open eye for a good condition used cylinder head to build as I ride the bike some. Is it possible to get 10k or 20k miles more with the conditions of these parts? No one can say for sure, but I'm curious what the experts out there think

Quick aside: Just so you all know, this experience has been killing me for so many reasons, one of them being I ordinarily take pride in doing projects the right way, and I'm well aware the best fix is new parts/head. I bought this bike knowing it needed some minor fixes, but I didn't expect anything like this.

2) Has anyone ever successfully had their cylinder head repaired? I saw a link posted on this forum, but have yet to read of anyone having this done. The 12 0'clock and 6 o'clock positions on the head and the caps were the least damaged areas (nearly perfect), so I don't think plastigaging clearances really gives me any useful information in this instance. How does a person know if their cylinder head is even a viable candidate for these services?

3) Put the bike out of commission, and take the hit of finding a better cylinder head and start building it.
 

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I don't know what happened to your head in the past. I have never seen that plug come out of an intake cam.

What I will say is that your cam journals do not look trashed to me. In fact, they look quite good. This is what an oil-starved cam and journal look like, and even these are not as bad as some that we have seen:
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The most I would do with those journals is get some PlastiGage and check the clearances. Then I'd get a new plug and put it back together.

The plug being out of the cam should have had a bad effect on the intake cam, but perhaps there was enough oil flying about that you caught it in time. Still, the clearances should be checked.

Your KACR got loose at some point. That is usually bad but it must have been caught in time. This is what usually happens:
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It is not the cam that walks into the pedestal, it is the flappy bits of the KACR that get loose from their pivot and start flailing about and hitting stuff. When they are done with that, the end of the cam looks like this:
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I'm no expert but I'd echo Tom's comments that I've seen far, far worse as far as cam bearing surface damage. ......I can only assume that it couldn't have run like that for long or the damage could have been way worse. I think I'd check the cam/cam bore clearances as Tom suggested, replace the damaged bits and button her back up - OTOH, I know how anal I am and the other option would be that I'd send the whole head assy to Engine Dynamics in Petaluma Ca. and have them install their replacement cam bearings. I guess that's option 1 or 2 :)

Dave
 

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Discussion Starter · #5 ·
Well for first responses, that's a lot of relief provided!! So you guys don't think putting everything back together is a ticking time bomb? Assuming clearances check out ok of course.

The unevenly distributed wear plus the KACR eating at the boss (in the past), and the missing cam cap had me thinking things were moving around in bad ways.

How do I find a cam end cap, and what's a safe way to install it? I'll purchase the banjo bolts that improve oiling to the top end before reassembly.
 

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Discussion Starter · #6 ·
Oh yeah one more thing. If you see in the KACR pictures, there's a visible mark where it was once hitting the pedestal... Does that imply it never actually came fully loose? If it came loose wouldn't it be entirely shrapnel?
 

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The 12 0'clock and 6 o'clock positions on the head and the caps were the least damaged areas (nearly perfect), so I don't think plastigaging clearances really gives me any useful information in this instance. How does a person know if their cylinder head is even a viable candidate for these services?
Personally, I am surprised that the damage is not worse. But not totally amazed.
Have you seen the pic of my inlet banjo bolt with a machining chip restricting oil flow to both the transmission and the cams. OIL Pressure, How much Ya got?

Plasti-Gage revealed near zero actual wear on cam bearings.


The only thing that is concerning to me is the contact on the EX RH bolt tower. You need to re-install the EX cam & LH cam bearing cap and check the lateral movement. Does it or does it Not contact that bolt tower? (Believe it or not, JB Weld in the RH side of the groove of the LH bearing cap could re-set the lateral movement. Well lubed it shouldn't wear.)
Bearing caps are Not Sold Separately.

After checking the lateral movement of the cam, you need to place 3 (three) strips of Plasti-Gage on each cam journal.
At 10 / 12 / 2 o'clock positions and check the suspect clearances in 1 fell swoop.

I'll bet that the bearing clearances are Well With-in Specs.
0.030 - 0.064mm (0.0012 - 0.0025 inches) STD / 0.015mm (0.00059 inches) Maximum

I'd order a 92066-1154 crankshaft soft plug $3.07 and see if it fits or take the intake camshaft to auto parts store & hope to match it. Install with Loc-Tite Red or Green and reassemble it. Ride On!
 
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Steal of a deal for some one!
 

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Discussion Starter · #10 ·
Personally, I am surprised that the damage is not worse. But not totally amazed.
Have you seen the pic of my inlet banjo bolt with a machining chip restricting oil flow to both the transmission and the cams. OIL Pressure, How much Ya got?

Plasti-Gage revealed near zero actual wear on cam bearings.


The only thing that is concerning to me is the contact on the EX RH bolt tower. You need to re-install the EX cam & LH cam bearing cap and check the lateral movement. Does it or does it Not contact that bolt tower? (Believe it or not, JB Weld in the RH side of the groove of the LH bearing cap could re-set the lateral movement. Well lubed it shouldn't wear.)
Bearing caps are Not Sold Separately.

After checking the lateral movement of the cam, you need to place 3 (three) strips of Plasti-Gage on each cam journal.
At 10 / 12 / 2 o'clock positions and check the suspect clearances in 1 fell swoop.

I'll bet that the bearing clearances are Well With-in Specs.
0.030 - 0.064mm (0.0012 - 0.0025 inches) STD / 0.015mm (0.00059 inches) Maximum

I'd order a 92066-1154 crankshaft soft plug $3.07 and see if it fits or take the intake camshaft to auto parts store & hope to match it. Install with Loc-Tite Red or Green and reassemble it. Ride On!
Thank you for your response and for the plug part #, I couldn't find that one anywhere. I will definitely check lateral movement of both cams.

When you speak of using JB Weld to re-set the cam lateral movement, I understand the concept of what you're saying but I'm unsure how that would be done or what that would look like. I have to tell you, on a scale of 1-10 (10 being great) my feelings of JB Weld in general are a 1. In many past projects I have had JB Weld fail on me.

I've tried every 'trick' to get that stuff to work. Perfect 50/50 mix, mix until its ready then mix some more, 60 hardener 40 steel and vice versa. Saying I would be hesitant to use in inside an engine is an understatement. Mind you, I am aware people use that stuff in engines somewhat frequently with apparently good results. However that hasn't been my experience, and my gearhead friends and myself have had results all over the map with that stuff from failure to total success.

As far as your oil mods go, I thought the idea was to increase oiling to the top end and to the transmission? I have the 3 required banjo bolts in an online shopping cart, and thought it was as simple as removing the oil line and putting the correct bolts in the correct places. In your link, I think you meant (please correct if wrong) that there was accidentally a chip limiting the oil flow to the top end and transmission, yes?
 

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I have used JB Weld for all sorts of things with never a failure. Paul and I are using it inside the clutch cover and the oil filter cover to do the 100% filtration mod. In there it is both mildly structural and exposed to 195*F oil. That's similar to what JB Weld would see if used in the cam caps to repair endplay.
 

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As far as your oil mods go, I thought the idea was to increase oiling to the top end and to the transmission? I have the 3 required banjo bolts in an online shopping cart, and thought it was as simple as removing the oil line and putting the correct bolts in the correct places. In your link, I think you meant (please correct if wrong) that there was accidentally a chip limiting the oil flow to the top end and transmission, yes?
The PDW oil mods are intended to reduce possible higher speed oil consumption, to some degree. (Less oil on the cylinder wall.)
The side effect was I felt the need to not just waste the available oil volume and therefore put it to better use, in the cam bearings and transmission. Nearly exactly like Kawasaki did do on the KLX series engines, maybe a smidgen 'better'.
That pic was at the beginning of project. That was a "WOW" moment.

So by all means, order those banjo bolts & use them in the suggested locations.

You could ask an expert welder / machinist to reduce the groove width (RH side only) in that bearing cap if necessary.
Possibly only need .010 - .020" lateral movement reduction. I'd JB it & ride it.
 

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Discussion Starter · #14 ·
Semi-update:
I am in the process of plastigaging the journals. Turns out the head on my 3/8" drive in/lb torque wrench doesn't have clearance because of the frame. I ordered up a 1/4" drive one hoping it'll fit!

I removed the oil line in advance of getting the new banjo bolts, and painted the line because mine was starting to pit.

So I've been doing some reading on KACR's. It seems the consensus is that when they contact the cylinder head pedestal it's usually from wear caused by low oil making the KACR being loose/worn not from cam end play. With my cam caps NOT torqued, but barely snugged, the amount of endplay I'm seeing looked fine, and that was without chain tensioner or upper guide doing their jobs.

The reason I'm nervous to say the least, is that the KACR spring and arm are IMO insanely close to that pedestal. Previously mentioned, it looks like at some point they made contact, maybe until I recently disassembled everything.

I'm going to measure the clearance soon but the weather stopped me today. I can say it looks extremely minimal. Also with light pulls the arms of the KACR have give on their axis. I know it sounds crazy, but I'm debating filing the already damaged areas of the pedestal with a file just to take out any potential high spots.

I don't suppose someone with a cherry condition top end can measure their clearance for me ! Even if my bearings clearance is ok, I'm still determining if the KACR needs to be addressed now.
 

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It's not a popular opinion and I understand and agree with the usual comments as to why, but if that was my bike, I'd consider just removing the KACR......my bike is stock compression, I don't have a kickstarter and my LiFePO4 batteries seem to spin the engines over more quickly than the stock batteries ever did so I'm thinking I may not have any noticeable side effects from running sans KACR.....but then, I haven't tried it only talked to those who have (which provides a nice mix of contrary opinions!)

(running for cover from Tom and Paul!)
LOL

Dave
 

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I know it sounds crazy, but I'm debating filing the already damaged areas of the pedestal with a file just to take out any potential high spots.
There is the Oil Drain-back Hole directly under the KACR. You could plug it with a cotton ball and suck up your filings & the cotton ball with a vacuum cleaner when done.

Yeah, we all know that the KACR pivots seem kinda sloppy. But it has got to be lateral clearance in the LH bearing guide groove that allowed the contact with the bolt tower.

I Plasti-Gaged the most wearable, most easily damaged RH Ex journal in my early modifications.
 

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Discussion Starter · #17 · (Edited)
The thing is, I don't know if the KACR *once contacted the pedestal or if it was still when engine was running recently. I looked at the cap groove, it's so narrow I can't imagine being able to apply, and then smooth out JB weld in there without damaging anything while cleaning the jb weld up.

Does anyone know if there is an endplay specification anywhere? Seems like if there was, I could file away and put my worries to rest.

Isn't it the left hand exhaust cap that locates the cam in terms of end play?
I suppose I could measure the camshaft groove with a caliper, and the cap recess. Keep applying super thin coats of JB on the cap groove until the fit is tighter?
 

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Huh?, "if the KACR once contacted the pedestal or if it was still when engine was running recently"?

The KACR rotates continuously with the exhaust cam from cranking speed to red-line. But its acuator pin is only contacting the RH EX valve tappet at well below normal idle speeds.

How about just holding the LH EX cam bearing cap in your hand, insert the exhaust cam guide ring into the guide groove and measure the clearance with a feeler gauge?

If the KACR can not currently touch the RH bolt tower, how & when did the bolt tower get roughed up?

A few slices of Plastic coffee can lid could easily be substituted for the steel cam shaft guide ring IF ANY JB Weld is even needed in the guide groove. Then easily extracted after JB Weld has cured.
 

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(running for cover from Tom and Paul!)
No need for that, Dave, because I agree with you. When my bike was at stock compression I removed the KACR. I still have that cam in my spare head.

It wasn't until I went full retard and did the kick starter with high compression that I felt the KACR was a good thing.
 
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Discussion Starter · #20 ·
I understand what the KACR does and I know it deactivates at half the idle speed rpm.

Without a torque wrench that fits, I'm not going to bolt everything (all caps for both cams, tensioner, guide etc) back together prematurely and risk over tightening
something just to see if it makes contact. Once I have a torque wrench that fits yes I will check if it makes contact.

I will definitely check the clearance between the ridge/ring and the guide groove with a feeler gauge and report back. Is that the .0015" you were mentioning? By eye I'm betting it's more than that.

The reason I don't know if it was contacting the pedestal recently is because I didn't hear anything while the engine was running, and didn't see/find any metal in the oil/magnetic plug. Obviously it HAS contacted, I'm just not sure when--that's all I meant by that, and surely I'd be a fool to not ensure it doesn't again.

Remember, this bike is new to me. At some point a PO could have done something to loosen the cam chain (perhaps) thus allowing more movement than is typical/good.

On a side note, is it the starter motor itself, the solenoid, or the gear teeth that are strained too much by removing the KACR?
 
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