Well, finally got around to adjusting the valves. Bought the special tool, made a spreadsheet for calculating new valve shim size, and got to work. The engine ran pretty well before I adjusted the valves, but I could tell it needed top end work and probably a go-through of the carbs. But, I wanted it mechanically sound before I started trying to clean and tune the carbs. Anyways, the valves were way loose, many being .008"! Got them dialed in, all were .002-.003" except for intake of cylinder 3 which I could only get to either .000" or .004" based of the new shim sizes, so I chose .004" (based off of what I've read here, go loose if you have to).
After the adjustments I put the bike back together and she fired right up! I let it idle until it would run without the choke on, and killed it to finish putting it back together and gather up my riding gear. A few min later I attempted to start it again, and it cranked about 2 revolutions at normal cranking speed, but then quickly slowed cranking speed until it no longer turned over. At first I assumed the battery was dead since it had sat for a few months. I put a new battery in the bike when I bought it, so the battery is only a year old. I let the battery trickle charge all night and I tried again the next day. Still no crank, but the solenoid would click. Next I tried to use the 50 amp start function of my charger; no crank, only solenoid click. Tried jumping with a car battery; no crank, only solenoid click.
Next, I started inspecting wiring. The neg battery cable to the engine block was corroded at the block, so I removed the cable and cleaned the ground. Tried again, no crank, only a solenoid click. Checked static battery voltage, 12.4 V. When I press the starter button, voltage drops to about 11.6 when measuring at the battery. I measured voltage at the starter and it is about 11.5 V. I suspected maybe the brushes are worn so I tried to old "light hammer tap" trick, but still no crank. However I noticed the starter has a slight hum and almost acts as if it wants to crank, after the hammer tap.
So based of these findings, I'm suspecting either bad brushes or windings. Does everyone agree or disagree?
Also, how do you remove the starter in a GS850? I searched this forum but wasn't able to find starter removal for this specific engine. I did find mention of removing carbs and chain tensioner, but not the crank case cover. However, this was for smaller engines. Is it really necessary to remove the carbs and chain tensioner on the 850, just to get the starter out? I have PDF version of the shop manual for this bike but I don't think it's complete because there is no starter removal procedure anywhere. Only inspection once it's removed, and in one section it briefly mentions removing the two starter bolts and tapping it out. Other than than, no mention of the starter cover, starter cable, carb removal or anything else. Any help is appreciated. Thanks!
PS - I'm aware of the "new bike owner maintenance must do's" threads. I will be getting to those items next. First thing is getting it running again.
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