I managed to check off one of the big jobs on the 990 today. I finally got to the point where I had the time to do my valve clearance checks. It isn't a particularly difficult job, but it is fairly extensive with regards to removing all the parts in order to make the checks correctly. And you do want to do it correctly. The guy I apprenticed under said it was one of the jobs you always want to get right. So, in normal anal fashion, I took time to research the job beforehand. I needed to make sure I not only knew the job front to back, but had all the tools required.
As I got into the job I was happy I did all the prep work. It made a big difference to the outcome. Also, although I am claiming success, I really can't know how good a job I did until I fire the bike back up and see if any of my valves impact my pistons....Seriously. that's the sort of thing that keeps me awake at night...I know I'm not normal. Just ask my wife, she thinks I was one of those children left behind...on purpose.
I got an early start on the bike, so as to ensure I had enough time to complete it. No way I wanted to go to bed and continue the next day. Anyhow, the bike has been stripped down to the point that it should be ridiculously easy to do. Normally, I would only need to remove a third of the parts I had up to this point. Anyhow, the first order was to open the rear cylinder. I had decided to do the bike from the back to the front. No special reason, just started that way. Each cylinder has four valves in it, making for a total of eight valves in the motor. Each cylinder has two intake and two exhaust valves. These valves are set individually by changing out small shims that regulate how far the valve moves when compressed by the associated cam shaft. The shims are held in place by buckets that the cams actuate. So beginning at the rear cylinder, I first removed the valve cover to access these parts. In order to do that I first removed the spark plug coil.
First off, some of the many tools I used...this is about half. I was lucky and didn't need the hammer, but was ready for it.
Anyhow, the back cylinder, the coil is the black plastic deely bobber.
Once out, I sprayed contact cleaner into the hole to clean out and dirt
Using the spark plug wrench to remove the plug afterwards (this is the front cylinder, as this much needs to be done on both cylinders before checking the valves).
Then those four 10mm bolts come out and the cover lifted right off.
With that done, the 14mm access cover needs to be removed on the left side engine case. It's the round thing under the LC8 label.
Inside the cover there is a place to install a 14mm allen socket onto the rotor to turn the engine to top dead center (TDC). So, as you probably suspected, I did that.
Then I dropped an unsharpened pencil through the spark plug hole to the top of the piston. This works as a visual guide to help you find top dead center of the cylinder. A sort of back yard cheat. Watching the pencil I rotated the engine counter clockwise (anticlockwise for you English and Aussie types) through two complete cycles to get an idea of what was going on with the valves, the piston and the cams. Each complete cycle includes two rotations of the crank and only one of them is TDC. I knew from reading about the job, that for the rear cylinder, TDC happens when the lobes of both cams point towards each other...thusly
Even though I know that is TDC, thereis a mark on each cam that helps verify it...a little circle that lines up with the case. There is one on every cam.
Now,before you go another step, it is at this point you need to lock the engine in place so that it doesn't move. KTM makes a screw tool that does this, but I got the same thing from CJ Designs. It threads into a bolt hole on the right side of the engine. This is the tool...(above the pen...duh)
And here it is in the locking position.
It's at this point that the cams are not touching the buckets at all and the gap can be measured by a feeler gauge. For the intake valves, spec is 0.01 to 0.015mm gap. For the exhaust valves, the spec is 0.025 to 0.030mm. This is where I made my first mistake...The smart among you will see my mistake. I looked at this and thought the gap was right on the money, totally neglecting the fact that I was reading the gauge in inches and not millimeters.
I did the checks of the intakes and then the exhaust and everything seemed perfect...then I realized my mistake. The gaps were way off. Fearing I had misunderstood something along the way, I gave the former owner a call and had a chat with him about the last time he did the check. While chatting we both realized he had done the same exact thing as I had, used the SAE measurement where he should have used the metric side. That made me breathe a huge sigh of relief. Even though the intakes were twice what they should have been, the bike had been running fine, although it made a light ticking noise. Clay had chased his tail looking for the cause of that and replaced the cam chain followers trying to get rid of it, while all the while it was from too wide of clearance of the valves. With valves, too close is way worse than too wide. No problem, I had a shim kit, so I could correct that.
The spark plug shaft insert is easily pried out with a couple of screwdrivers. I was super careful not to nick the cams on each side and the next thing to do is to remove the cam bridge. It is held on with eight 5mm screws, four are large and four are smaller. The large screw on the right side near the frame was a pain to get out.
The bridge lifts right off the cams fairly easy. Each bucket is easily removed with a stick magnet. You need to be careful because the shims can be stuck to them and drop where you will never find them, or worse, into your engine. Here the buckets are all removed and you can see each shim on the valves.
Removed.....Notice I plugged my plug hole with a towel?
Then out comes the digital calipers and each shim is measured. Oh, I had been writing all the valve clearances and then the installed shim sizes for each valve as I went along in a notebook...
Once you have both numbers (shim size and clearance), you have to do math...I love math even though I suck at it. There are actually three different ways to figure out the correct shim size: math, you do the work in your brain; an excel spreadsheet set up by the most excellent Kamanya, which does the math for you assuming you have Microsoft Excel; and finally there is a KTM chart that does the math for you, you only have to follow the clearance in one column and the shim size in a row to the corresponding correct new shim size.
The chart of intake valves
The chart for exhaust valves
I used all three methods and the numbers all checked out. Then out came that shim kit and I grabbed the correct sizes to set the clearances, making sure to mike each shim out to make sure it was correct.
Then the correct new shim goes onto the right valve and the bucket gets put back onto each. I put each bucket back into it's original spot as well. Pays to be careful. Then each cam is placed back into it's original spot (there are specific cams for each spot on both cylinders, so a rear exhaust only goes to that one spot and no where else)
Rear exhaust cam in correct position, see the circle/dot?
Rear intake cam
Both back in the engine.
After that, the cam bridge goes back on and gets torqued down to the correct tightness. I used my little Park torque wrench as well as my old school Craftsman from back in the 80's (bought new by me...my first really cool tool).
The bigger bolts are tightened to 18nm and the smaller bolts just to 10nm. It is important to retighten the bolts in a star pattern. Then I checked all the clearances one more time to make sure everything turned out right. Guess what? They were perfect!
Back in went the spark plug shaft insert and then it was easy enough to lube the cover gasket and reinstall the fixing bolts with a 10mm gear wrench...One down and one to go.
I was happy how easy that had been, even with chasing my tail over the feeler gauge mistake and was toasting myself for a successful job...yup...I was about to hate life. The front cylinder has a ton more room to work in with that oil tank and radiator removed and I suspected it would be a pretty quick job. Boy was I in for a surprise. First the locking screw is removed and the engine is put at TDC for the front cylinder. That is the exact same process as the rear. Once at TDC, the locking screw goes back in and the cover is removed, just like the rear. Once off, I was greeted with this view. CRAP!!!
See the spark plug shaft insert? See that enormous layer of dirt? See the dirt that has already fallen onto the front exhaust cam? Ever hear a grown man cry??? It was between the cover and insert. As I lifted the cover it fell onto the exposed cam and into the space around it. Into the pooled oil in there as well. Holy crap, to make matters worse, there was a bunch inside the plug tube. I had really sprayed it down with contact cleaner, but didn't look close enough...obviously... I stole my wife's bathroom mirror and took a good look in there and was not happy. It was wet and I hoped that none had fallen into the combustion chamber.
Anyhow, after carefully measuring the clearances, I very carefully removed the cam bridge and cams. Then, with the buckets in place and using a oiled towel, I cleaned the dirt out of the top of the engine. I used the mirror to check spots I couldn't easily see and then when I was happy it was spotless, I put a shop towel over it and cleaned off the cams, cam bridge and spark plug shaft insert. Then I lifted the buckets and shims out and cleaned some more to get every grain out. All told, it took me an hour of work to get things spotless again. Then it was back to the job...measuring shims, doing math, reinstalling things...Real Men of Genius type stuff (and if you get that reference, I'll buy you a cold one....no, really. I will).
That's it for the valves (although, as I write this, I already am thinking of taking both covers off again to recheck everything. It's a sickness). Anyhow, at that point it was time to clean the coils off and hit the connectors with some Corrosion X.
Both are clean...the zip tie is so I remember this coil is for the front cylinder. Does that matter? It does to me.
New spark plugs were next. Some Iridium plugs. I put some anti seize on the threads, I love that stuff.
By the way, there is a screw on tip for each plug that needs to be removed for these bikes...did I remove it? Not on the first one. Moron. Then when I pulled it back out, I dropped it. PINHEAD...oh that sucks.
Anyhow, eventually after all the idiocy, I finally got things reinstalled and looking nice again.
Then the locking screw came out and put away as well as the left side plug hole re plugged.
That could have concluded the days fun, but I was on a roll, so I tackled the oil jet and clutch slave reinstall since I had time and since Mr. Postman had delivered them.
First I cleaned the area off
Then installed the new oil jet...you can see the hole on this one...
Put a new crush washer on the cover bolt and reinstalled it
Then the clutch slave and sprocket guard assembly go back on
Finally, I put the sprocket back on with a new safety washer along with a new chain slider and the old chain roller
Then, since I knew that I could reinstall the clutch plates and clutch booster through the clutch cover, I put the right side engine case back on with a new gasket, making sure to torque them to 10nm. . I made sure to clean any dirt off that had gotten into the side as well as cleaning the water pump cover for the same reason. I am ordering a new water pump cover gasket along with a couple of o-rings and will replace them when they show up in a week or so.
That was really enough for me. I was ready for dinner and some sleep. Lo, I had forgotten to put my wife's mirror back in the bathroom and she found it in the garage. Of course I didn't know that she had found it and had also looked at our recent credit card bill with all sorts of motorcycle related charges...If you are married, you know how much trouble I was in. If you aren't married, maybe this will help you decide if you ever want to get married. Some women scream and yell when they get mad, my wife gets all sweet and innocent. She poured me cold beer that night. I thought she was in a great loving mood. I had no idea it was roofied. It knocked me out COLD. In the morning I awoke with a headache and a feeling of fear in the pit of my stomach. I ran to the bathroom and saw the horror she had wrought. That sweet, wonderful love of my life had shaved me bald. Not since basic training for the Army had I been this bald...
OMG, where once I had long flowing locks, I was now shaven clean...buddhist monk style.
No worries...revenge will be mine. She will pay...but I gotta make it look like someone else does whatever I decide. That woman is mean and I don't need her to up her revenge game on me.
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