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TOPIC: Re:bike is dead...
#551134
ks_scot (User)
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bike is dead... 5 Years, 4 Months ago  
Ok, this could take a lot of explaining, but I need some help!
About 6 weeks ago, I left on a trip (100 degree heat, if relevant), bike running great except that the battery appeared to be weakening. I put a new battery in last year, but recently, it was slow turning over to start. Once started, no problems.

About 50 miles into the trip, I stopped to fill up, shut the bike off, filled up, restarted, then parked by the front door to eat breakfast. came back out, wouldn't start (sounded funny - like no compression - starter was spinning, exhaust popped, but didn't sound like it was trying to start at all).

Got it towed to a shop, where it miraculously started running again. They couldn't get it to fail, so off I go again. Another 150 miles down the road, I stop for gas, fill up, restart, and go park to get a water. Came back out, same problem as described above. Towed to a shop, they ran tests for hours, and came up with nothing. All fuses, relays, etc. good. Spark to plugs, fuel to engine, all good. They thought it might be the stator - it wasn't.

Trailered the bike home, took it to a local shop. Many tests later, no problems found EXCEPT 2 valves stuck open! They wanted to do a top-end overhaul / valve job, I said no.

Talked to a different mechanic that seemed to know the Roadie inside out, and he thinks it's the auto-decompression come to haunt me. Something to do with the combination of a weak battery and not shutting the bike down in the proper sequence. Actually, he's made the most sense of anyone so far, and said that it "may be possible" that a new battery would fix the problem.

You guys are the smartest mechanics on this bike - has anyone ever had / seen / heard of this problem? I could sure use some help & encouragement!

Thanks!!
Ks_Scot
 
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#551138
SKWEARpeg (User)
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Re:bike is dead... 5 Years, 4 Months ago  
So it wasn't carb puke that was killing your bike in the heat at the time??? Is it running now, and your scared it will quit again, or its not running at all, because the battery is dead?
Once a battery gives up the ghost, you will probably have problems even trying to jump it, if the battery has failed internally.
A new battery is an easy enough check.
I have no idea what this "not shutting it down in the proper sequence is about". If it is the decompression solenoid, then you can manually operate it by removing the cover, and moving it with a finger while you try and start the bike.
There are members here who can instruct you on just how to manually operate it, I'm not one of them.
 
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#551142
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Re:bike is dead... 5 Years, 4 Months ago  
From what you are describing, it sounds like your decompression solenoid is sticking. I'm not sure how a new battery would fix that.
 
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#551147
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Re:bike is dead... 5 Years, 4 Months ago  
My first thought is just carb puke. A lot of guys here (myself included) turn the fuel off a little ways before actually shutting the bike off. Especially in high heat or on longer rides where you're just stopping for fuel. Add to that, the battery cables are a bit on the small side. I took many long rides this summer in high heat. If I didn't turn the fuel off a minute or so before coming in for a gas stop, I had to crack the throttle wide open to make up for all the gas that puked into the intake manifold. Even then, it made some strange noises and/or didn't want to crank like normal. That's after replacing all the battery cables with larger ones.

I'm not saying it can't be valves or a problem with the decompression solenoid. Just relaying my personal experience. The bike cranks and starts much better when shutting off fuel flow a few seconds before shutting down.
 
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#551151
jd750ace (User)
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Re:bike is dead... 5 Years, 4 Months ago  
The decompression solenoid is actuated with the same power that runs the start solenoid. A weak battery sometimes will deliver everything to the start solenoid, which is the path of least resistance for the amperage, and there's not enough left over for the solenoid. If you pull the cover off, when you attempt to start, you can see the solenoid plunger extend. You can pull it outboard with your finger to full travel, and see if that's how far it is being pushed by the solenoid. It should be de-energized in all conditions except starting. You can try to push the plunger inboard also. If it moves inboard at all (motor off, of course) it is not retracting properly, and will hold a valve open on each cylinder when you should be compressing.
 
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Last Edit: 2012/10/13 21:56 By jd750ace.
 
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#551152
ks_scot (User)
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Re:bike is dead... 5 Years, 4 Months ago  
The battery is not dead - the bike still will not start (now 50 degrees here). Valves are still stuck open, no compression, starter spins, have fuel and have spark.
 
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#551154
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Re:bike is dead... 5 Years, 4 Months ago  
The response from jd750ace sounds like what the last mechanic told me - makes sense to me, I just need some verification from you guys!
 
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#551157
Deerkiller (User)
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Re:bike is dead... 5 Years, 4 Months ago  
How exactly do you know the valves are stuck open?
 
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#551159
jd750ace (User)
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Gender: Male jd750ace Location: Waxahachie Texas Birthdate: 1969-10-30
Re:bike is dead... 5 Years, 4 Months ago  
With no compression and and intermittent failure, I'd suspect the solenoid sticking. I have not heard of the relar rod failing(the little paddle on the outer end of the decompression solenoid is mounted to the inside of the side cover in a pivot mount. It has 2 fingers inside the case. They push rods through the center of the camshafts, that raise a little bump on the outboard exhaust cam lobe of each cylinder, and they bump that valve open just before TDC, to relieve peak compression for faster cranking.) The manual says the solenoid is de-energized after the engine reaches a certain speed. That speed sensing would come from the pickup coil on the crank. I don't think that's your problem, since you don't show compression. That's usually "no spark" for a symptom, but cranking speed and compression are not affected by that one. I'd check the solenoid first. If the solenoid is good, you could have a stuck valve in each hole,(SVS?) but you do not need a "top end" job at this point.
 
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Last Edit: 2012/10/13 22:13 By jd750ace.
 
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#551163
ks_scot (User)
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Re:bike is dead... 5 Years, 4 Months ago  
Borescope test revealed one valve stuck open in each cylinder - mechanic couldn't remember, but believed they were both on the intake.
 
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