Hello folks.
I have been dreading penning this to paper for about two weeks.
Here is the background on the bike: 1976 kz900 which I have owned for 8 years and put 15k plus miles on. Bike has 46k total. Last year I pulled the engine and painted the frame, re wired a lot of the bike and freshend up the top end (1015cc kit, new cam chain idlers & guides, and valve job by PSP). Dropped the oil pan to clean all the sludge out and clean the screen. Everything looked fine. I did not split the cases - hence original cam chain, didn't weld the crank, etc. I pretty much ran out of time and did not want to go any further. With the addition of a Jardine exhaust, Lester mags with dual disc Z1 front end, custom handlebars and everything either painted fresh or powder coated it was as close to a ground up job as I wanted to do. Bike is running stock cams and carbs(vm26) and Dyna S ignition with Dyna coils. I am really proud of my bike. I did pretty much everything except the head work, boring of the cylinders, and powder coating. It was a mix of work for 'show' and for 'go'
I have about 600 miles on the bike since I put it together earlier this year. I followed the break in procedures to the letter and was gentle for the first 100 miles or so. I'm not going to say the bike ran perfect because it didn't - slight midrange hesitation and an occasional backfire (blew #1 & 2 vacuum plugs off once) as well as an intermittent oil light / oil pressure problem experienced by many. There is an oil cooler and an analog pressure gauge in place - the few times the pressure would drop I would pull off and let it cool and everything would be fine. I had feedback suggesting this could be due to the oil cooler and to run a heavier weight oil. Every time the bike started I had good pressure which would lower as it warmed up.
I know that the mid range hesitation and other hiccups were warranting some carburetor tuning and maybe a timing adjustment but I had not gotten around to it yet. I had rejetted the carburetor for the air filters / exhaust before the engine work and it ran pretty well and I balanced the carbs using my Carbtune.
I would like to say also that upon the first startup after putting everything back together it was like night and day compared to how it was before. Carbs really easy to balance, consistent header temps, etc. I was meticulous when assembling the engine and I am confident that the quality of work done for the valve job / overboring was good.
Anyway, took the bike on a 200 mile ride three weeks ago. 100 miles to my destination, and 100 back. I'm not going to kid myself or anyone else - I was riding pretty fast for most of the ride home. Traffic was getting worse and I was hauling ass. About 10 miles away from home I pulled off on my exit.... bike died. Would not start. I was still getting power to everything. e I pushed it to a gas station and thankfully someone gave me a ride! Must've been karma as I had given a couple bucks to a homeless dude at one of my gas stops.
SO, I returned the next day with some tools - here is what I found: I was getting spark on all cylinders. It did appear to be a weak spark. Only getting 9v to the coils. Getting fuel. The mechanical ignition advance is not stuck (I figured that would be an easy way to make the bike not run on any cylinders) Compression test was pretty inconclusive because I couldn't start the bike and the battery was basically dead. The numbers I was getting are scary and I attributed it to incorrectly testing (using the kicker). The only thing I got was one backfire out of the exhaust.
I got my truck and loaded the bike up to take home. Drained the oil - The oil was low. Probably 1.5 qts low (it was full when I left). The oil has a sickening burned smell to it. I mean, it smells terrible. Maybe the ZDDP makes it smell?
No metal flakes or shavings in the oil that I could see.
When I crank the bike it sounds kind of sick - not sure if the starter sounds sick or what? Kicking it over feels completely normal - no strange noises or anything like that, smooth action with the same resistance I am used to. The plugs look like they were running hot, maybe too lean or timing too advanced? Exhaust also looks bluer than it was at the start of my ride...again, these were new headers so they only have 600 miles on them...
I have not touched it since. Unfortunately between work, having a small kid, and multiple bikes I have to use time wisely...and honestly I am kind of dreading getting into this. I know the oil consumption ain't right. It does leak a bit from the stator grommet and front right cam cap, but there is no way in hell all of that leaked out on the ride. A few years ago I tried a low profile breather on the bike - I know what losing that much oil on the road is like (everything from the breather back literally dripping with oil at the first gas stop).
I suppose my next move is to pull the cam cover and see how the cams look or if maybe the chain jumped a tooth? Whatever happened is affecting the whole engine. Even if one or two cylinders had problems (fouled plug, carb problem, stuck valve, anything that would affect a single cylinder) the engine would run shittily on the remaining cylinders. Everything is pointing to some sort of timing or ignition issue - I need to check the ignition timing as well, although the dyna-S plate had not moved a millimeter and the screws were tight.
Oh yea, almost forgot - When I was scratching my head thinking about the weak spark / 9v to coils (relay mod has not been done - factory power distro to coils) I decided to measure the resistance between the 3 yellow stator wires (idea was if the bike is not producing power the battery doesn't have enough juice to make good spark and turn the engine over - kind of a long shot since it is a new battery, etc.) BUT here are the resistance readings -
Between 1 & 2 - 1.6 ohms
Between 1 & 3 - zilch
Between 2 & 3 - zilch
I verified this test with two different meters multiple times. So this leads me to believe the stator has faulted somewhere. Could this be related or unrelated to the bike straight-up dying, not starting at all problem?
Anyhow, I am curious to hear any input / advice / sympathy / criticism from ya'll. Attached are some pictures I took during happier times.
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