[Tom Schmitz]

Some more considerations here:

Compression Tests/KACR and KACR-less

Based upon the number of reports of KACR failure (it's uncommon, but I attract disaster) and folks saying that they removed their KACR and had no problems, I removed mine. I have had problems with occasional kickback while starting. Also, if the piston stops on the verge of a compression stroke...

www.klrforum.com

 

[TaylorW]

I should think that if the rivets are good and solid that the KACR should be healthy. Candidly, I wonder how many 'KACR failures' are not preceded by running out of oil and roaching the exhaust cam journal.

this is definitely one added concern; if the scorching of the exhaust cams during the initial incident could possibly have fatigued other parts of the cam, ie the kacr. I will double-triple-quadruple check the integrity of the rivets. With your experience, is lateral play in the kacr mechanism normal?

An unmodified KLR engine (in terms of compression ratio and valve timing) can work well enough without a KACR, but the battery needs to stay in good shape.

So my 685 piston upgrade theoretically wouldn’t make it even harder to start without the kacr?

 

[pdwestman]

TaylorW, The pin your arrow is pointing to is a pivot pin of the KACR system. Is it hitting the cylinder head interior surface somewheres?
Is the New LOWER cam bearing shell Not Tall Enough?

The Exhaust Lobes & springs would have more resistance to turning over at even one quarter of lobe lift than the KACR Actuation pin against the shim at a mere .030 inch maximum lift.

From the point of Proper Re-assembly, TDC with camshaft arrows pointing forward. The Exhaust Lobes would open the exhaust valves completely and allow reclosure of valves. Then the Intake lobes would open & reclose. And then the KACR actuation pin would contact the shim for maybe .030" of lift and 30-40 degrees of crank rotation. Then the crank would turn another 90 degrees or so to "F" mark & then "T" mark. 2 full rotations, 720 degrees.

I can not see any way that the KACR pin could have been your issue. It is SUPPOSED to stay Above the base circle of the cam until about 700-800rpm of crankshaft speed to do its job. (That is 350-400 rpm of camshaft speed.)

As Tom S. alluded to, I've never seen pics of an exploded KACR, head, valve cover that DIDN'T have a gaulded/over-heated/destroyed cam bearing 1st.

 

[TaylorW]

From the point of Proper Re-assembly, TDC with camshaft arrows pointing forward. The Exhaust Lobes would open the exhaust valves completely and allow reclosure of valves. Then the Intake lobes would open & reclose. And then the KACR actuation pin would contact the shim for maybe .030" of lift and 30-40 degrees of crank rotation. Then the crank would turn another 90 degrees or so to "F" mark & then "T" mark. 2 full rotations, 720 degrees.

this is exactly what it’s doing now. During my initial post yesterday about my suspicion of kacr error, I was misinformed as to its function and thought the actuation pin was supposed to retract into the recess when it cam in contact with the shim. It doesn’t appear to be coming in contact with the cylinder head interior, but the “sticking” I was noticing was happening at the moment the actuation pin was coming in contact with the shim.

Looking back on it, there is a possibility the first few times the cams simply weren’t timed correctly? I was being aided by a friend, who was rushing quite a bit through sections, and Im pretty sure the first bind was caused by cam chain slack in front of the exhaust cam. Another time I noticed he hadn’t tightened the center bolt of the cam chain tensioner. I was pretty trusting in his abilities, since he’s worked on bikes quite a bit...but today when I went back to the bike, I realized he was installing the cam chain tensioner with the new gasket...over top of the old gasket still stuck to the cylinder head! So maybe I wasn’t paying enough attention to things, and possibly when I was putting the engine at TDC, it was the “false” TDC, when the cam lobes both point inwards, rather than outwards?!

As Tom S. alluded to, I've never seen pics of an exploded KACR, head, valve cover that DIDN'T have a gaulded/over-heated/destroyed cam bearing 1st.

Either way this ^ has me heavily contemplating grabbing a new exhaust cam for peace of mind on the kacr front. But, and maybe there isn’t a definitive answer, is lateral play (side to side) of the KACR pieces normal in a healthy assembly (as shown in the video)? If so, I will likely order a new exhaust cam anyways, but finish putting every back together now, and install the new cam come my first low-mileage engine break-in oil change.

 

[Tom Schmitz]

...is lateral play (side to side) of the KACR pieces normal in a healthy assembly (as shown in the video)?...

Yes, it is, provided that the rivets are tight. The thing can't really come apart if the rivets are tight. If they are loose, then all bets are off.

If the engine gets starved for oil and the exhaust journal dies due to molten metal, heat, and smoke, then the KACR can start smacking into things and the rivets may be knocked loose. What follows that is not a graceful degradation...

 

[TaylorW]

Okay, went ahead and cheats the rivets and everything was solid. Got all the bits and bobs hooked back up and went to start, but no go, battery too weak from sitting, duh. Sat it on the trickle charger til full, hooked up, went to start, cranked forever, and every...like well over a minute. Thought that didn’t seem right and suspected something with the fuel delivery. Pulled the hose off the petcock and it was dry as a bone. I know my petcock would leak a bit ever since I got it and turned it to the “on” position, and I know the vacuum hose is a known problem, or maybe the fuel is gunked up from sitting in the tank for three months? Don’t want to turn this thread into one about fuel delivery, but if anyone has an inkling off the top of their head, or links to related threads, it would be much appreciated.

 

[pdwestman]

You can use an oil bottle with a tapered squirt Nozzle and a piece of hose to remote feed the carb without installing the fuel tank. Just poke a vent hole in the SIDE of the oil bottle, so it can feed the carb.
Just be sure to cap the vacuum nipple at the top front of the carb.

 

[TaylorW]

Ah okay nice. So just put the nozzle into the fuel line going into the carb. That'll at least let me narrow things down a bit! Thanks! Hopefully I can post up about the engine running soon! This has been one heck of a project.

 

[TaylorW]

Okay update, took a bit cuz I got kicked out of the garage the bike was staying in and we got some negative degree weather up here. But I had ordered the manual petcock and got that installed, put the rubber vacuum cover on the carb, recharged the battery, and no start still. Played around with the choke, accelerator, banging on the float bowl, opening the gas tank, just about everything I had read that was an easy try. This time however, in the one and half to two minutes I cranked the bike over, I got three very loud misfires, about 15-seconds apart.ni opened the float bowl drain screw and did get fuel out of it
Potentially spark plug related? I admittedly reused the old spark plug that was definitely not in pristine shape. Or carb related? Either way I’ll go ahead and order a new spark plug, cuz I should’ve done that in the first place.

 

[TaylorW]

Another update for those interested:
took the bike down to @pdwestman’s shop to have a more competent look over, and he quickly found the culprit, my left exhaust cam bucket is jammed about 1/8” down (and by jammed, I mean completely unable to get it to move in any which way), so the engine is getting zero compression. Quite the bummer since I had all of the valve assemblies gone through by Engine Dynamics, and I didn’t mess with the bucket or shims before putting everything back together, but I guess it still could’ve been my error somehow since it’s my first engine rebuild. 🤔

 

[TaylorW]

Final Update: it lives!!

I’m unlimitedly grateful for the immense help you all have been on this adventure! Paul is an absolute wizard with these machines, and I’ve gained a lot of knowledge on these bikes, and a new appreciation for engines 😂 here’s to thousands of miles 🍻

 

[pdwestman]

Thank you Taylor for the kind words. Thank you for your patronage.

Check your engine oil every morning, until you KNOW your bikes habits, even after its repairs.
Here is 3 beers to many 10's of thousands of Happy Miles!
Ride On.

 

[SoCalTrailrider]

Final Update: it lives!!

I’m unlimitedly grateful for the immense help you all have been on this adventure! Paul is an absolute wizard with these machines, and I’ve gained a lot of knowledge on these bikes, and a new appreciation for engines 😂 here’s to thousands of miles 🍻

Taylor, it's been a journey, love hearing her purr. I'm anxiously waiting for my 692 from EM. I had similar issues with my exhaust cam. Hoping the machine work will be a breeze. I am putting a new exhaust cam in though. It just wasn't up to par.

Notes: I bought mine with about 5k miles on it 7 years ago. I constantly watched the oil and she was never a user until my last ride about a year ago. At 18k miles she went through oil like crazy. A qt in 400 miles on our extended 3 day ride up the Certainly California Coast. She sat waiting for funds until this past week. Looking forward to that first run and the break in period being complete.

Just did my door today. Not broken, but spring was off of it. Will do the clutch plates next, with a new cable. New oversized front roto, skid plate, crash bars, and shock. It'll be like a new bike... might even do a wrap. 🤔

Cheers!

Tim - SoCalTrailrider

PS: Thanks to all, great thread! Braap!