|01-08-2013, 11:28 PM||#1|
Joined: Mar 2011
Location: Salt Lake City, UT
KLR650 Engine Rebuild Photos and Questions!
I've always loved reading build journals. So, here I am, finally creating one of my own. Here we go.
Yesterday, I knowingly bought a 2003 Kawasaki KLR 650 that has engine problems.
The previous owner (PO) said that he purchased the bike earlier in the summer and the owners before him said that it needed the valves adjusted. After purchase, the PO brought the bike to his mechanic for the valves to be adjusted. The mechanic reported back that there was damage to the engine head which could only be fixed by replacement of the entire head. The mechanic quoted him at $2500.
I bought the bike for $800. My estimated total budget is $1500. I've seen some used heads on Ebay for around $300-400. I contacted a local motorcycle machine shop, and they estimated a basic head refresh at around $150-200. Let's see if I can pull this off.
It was late once I got my bike in my garage. I took a couple of crappy cell-phone pictures, sat on the bike for a minute and then decided to start tearing it apart.
I found a couple of nice surprises here and there. Some previous owner had upgraded the bike to a gel battery (but didn't remove the old battery overflow tube). I also found an IMS folding gear shift lever and an aftermarket foam intake. I'm not sure if this bike has had the doohickey replaced. It's definitely on my to-do list before this bike is back on the road.
I just did the basics that have to happen before almost any work is done. This is my first KLR (or dual sport for that matter) that I have worked on, but I felt safe in assuming that the seat and the gas tank needed to be taken off. Both were pretty easy and straightforward.
Fast forward to today. After work, I grabbed a decent point and shoot, and got right to wrenching.
12k miles. Not bad for a 2003. Just under 1,500 miles a year.
That's how the bike stood as of today when I started.
Single cylinder, four valve engine. Ready to be cracked open.
The first step is to remove the exhaust to vastly improve access. It's just held on with a couple of bolts. Pretty easy to figure out.
I shot all the exhaust bolts with PB Blaster. Makes life so much easier.
There's an exhaust bolt hiding behind the rear brake fluid reserve cylinder.
Liberal use of PB Blaster is recommended. I'm not sure if this is a stock bolt… All the other exhaust bolts were hex head. I was a little surprised to find an Allen key here.
The nut on the back fell off here. The others seemed to have been spot welded to the frame. It was easily found. I put all the exhaust bolts back on after removing the muffler. Definitely improves my chances of a correct reassembly.
Here's the muffler removed. Somewhat beastly. Is there a catalytic converter in here? Or is it just a spark arrester?
So much more room for activities…
Again, returning bolts to their original position and putting those you can't into well labeled plastic bags.
The header bolts were barely snugged. It was extremely easy to remove. Perhaps the previous mechanic didn't feel like torquing them down?
Ahh… much more room.
Don't forget the header gasket. This one was a little gnarly. Definitely some evidence of exhaust gas leaking past. Probably due to the loosely tightened bolts.
Another look at the header and gasket.
Time to start unplugging the radiator fan. Pictures are good for remembering where things go.
Note to self: Don't forget this ground wire!
Hanging the radiator fan out of the way.
Also, labeling generic wires is a man's/woman's best friend. Need to remove anything that comes out the top of the head to facilitate valve cover removal.
Unplug the spark plug. Looks like something may have been nesting down there at some point…
Remove the upper engine mount and bolts so that the valve cover can later be removed.
Looks like this once it is out.
Pop the gas tank rubber front supports out. Two reasons: more room, and I really don't feel like fishing one of these out of the bottom of the crank if it fell.
Zip tie some wires out of the way. I like using bright colors. Helps me remember to remove them on reassembly. Plus, it looks so snazzy!
Alright, the time has come. Let's loosen the valve cover bolts!
I like to slowly work my way around all the bolts. Probably OCD for the valve cover since it's not highly torqued down, but I feel it's a good habit to practice.
Pretty unique and interesting bolt. Note to self: don't lose or break these…
The left side (rider's left) has a different and shorter bolt.
Here's all the bolts laid out. Notice the difference between the right and left side. My finger is pointing in the direction of the bike's travel. These photos are helpful for reassembly.
I love baggies. Good labeling with a Sharpie is essential.
The Clymer manual didn't mention removing the bolt holding the—what appears to be—coil pack, but it made my life a lot easier when squeezing the valve cover out from under the frame's spine.
It took a little finagling to get the valve cover out. The best way for me to describe removal was to sort of wiggle it back and forth, while lifting up the left side over the cam sprockets and chain. Just be patient and don't force anything.
Also, be careful of the valve cover's rubber gasket.
Another shot of how it has to be shimmied up and away from the cam sprockets.
And it's out! Just needs a little Simple Green or Fast Orange (whatever your color-cleaner preference may be) and it will be good as new.
Finally, my first look at this bike's cams and journals. Doesn't look terrible… but I won't be able to tell until the cam caps are off.
I took a few pictures. Maybe a discerning eye will catch something I didn't.
Note the dead bug by the spark plug. I'll call him Timmy.
A view of the automatic decompression unit. Springs… my arch nemesis…
The cam lobes look like they are in pretty good shape.
A shot of the cam sprockets and the cam timing chain.
Ok. Now it's time to get the engine at Top Dead Center (TDC). It's pretty easy on these bikes. Just have to take the crank side cap (lower) and sight cap (upper) off.
Also, now is a great time to drain the oil.
It took a bit longer to get the oil drain plug off. It looks like a previous owner has abused it a little bit with an adjustable wrench perhaps. Tsk tsk. :) Should be easy for me to grab a replacement from the Kawasaki dealership.
This sign prevents any embarrassing stories.
Almost done draining…
While we're here and waiting for the oil to finish draining, let's check the oil filter for any metal shavings.
Oil filters are usually filled with oil. I've learned this the hard way enough times… sadly.
Actually, to my surprise, it didn't make hardly any mess at all.
Ghetto exploded views FTW! Not that the notched smaller end goes in towards the engine.
Looks like they put an aftermarket K&N filter in. Looks in decent shape too. Almost brand new. Didn't see any metal shavings or odd bits in it either. I'll double check to make sure this is the right filter. Seemed a little loose in there.
No metal shavings or bits in the drained oil either. Hopefully this is a good sign that the bottom and transmission are both in decent shape.
Where were we… oh yes! We need to get the engine at Top Dead Center (TDC). I believe this was a 19mm socket… Just turn the engine while looking in the upper sight hole until you see a T and the cam lobes are pointing away from the center of the engine. If they face inwards, you need another full rotation.
I was actually pretty surprised how easy the engine is to turn over. At first I thought that maybe the piston rings were shot, but I'm hoping that's the automatic decompression just doing its job.
Here's a shot of the cams facing outwards at TDC.
Before I take the cams out, it's a good idea to check the valve clearance and see how off they are.
I started with a feeler gauge that was right in the middle of the spec for the intake and the exhaust and then I'd work thicker or thinner depending on the amount of gap and resistance that I felt.
My fancy diagram before I filled out the valve clearances. It's always good to have stupid simple drawings for future reference.
Here's how the valve clearances are checked. It should feel somewhat snug, with some resistance in and out. At these gaps, you really shouldn't be bending the gauge to get it in the clearances.
One of these is not quite like the others… I think I found the problem. But, now I am starting to wonder what the catalyst for this was… The right side intake valve clearance is a little over double what it should be.
It's pretty clear at this point that the cams need to be removed. You'll need to remove the cam chain tensioner to continue.
First, loosen the middle bolt (don't remove!) and then remove the upper and bottom smaller bolts.
And boom, comes out easy as pie.
Working your way around, loose the cam cap bolts a little bit at a time. I discovered that the right intake cam cap bolts were finger tight. I wonder if this is what caused the excessive wear? Perhaps a previous owner or mechanic forgot to torque these bolts down when adjusting valve clearances? I love mysteries (as long as I can solve them).
Hrmm… there is definitely some gouging and excessive wear on the problem cam. I'm starting to wonder if this can be smoothed down, re-shimmed, and a new cam cap installed… Any experts care to chime in?
Here's that cam's cap.
The right side exhaust cam cap is also fairly worn. What could be causing oil starvation on this side of the engine? These bolts were also barely torqued down. Not quite finger tight like the intake side, but close.
Close-up on the exhaust cam. Again, I wonder if this is usable with some basic machining and cleanup?
Right side intake cam cap close-up.
Bagged as evidence… or just to prevent me from getting them mixed up.
Also, don't lose these. If they're snug in the head, don't worry about them. But, if they feel like they could fall into the bottom of your crank, it's a good idea to remove them and bag them with the matching cam cap.
Here's the left side cam caps. Interestingly enough, they are installed as a pair with an oil passage between the two. Pretty nifty. I haven't seen this before. The exhaust side looks brand new, but some mild wear on the intake side. I'm starting to wonder if this could be from some foreign object damage. The valve cover gasket wasn't exceptionally snug. All it takes is for some grains of sand to enter in here before it's a party…
I put some clean shop towels on the left side before continuing. I really don't feel like dropping anything into my crank case.
Unfortunately, I had to stop here. To remove the cam chain cover, I needed a skinny extension to reach the 8mm sockets. Definitely a 1/4" drive. I barely have any 1/4" drive tools. I'll have to pick some up tomorrow after work before continuing.
I'm really curious what the cause of the cam damage was. I'd like to find as definitive of an answer as possible before replacing anything with new parts.
Thanks for bearing with the bad pictures. I'm really excited to continue working on this project tomorrow.
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