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Author Topic: Bike lost power, ran very rough, now no start  (Read 8598 times)

Offline 400banditman

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Bike lost power, ran very rough, now no start
« on: October 22, 2011, 11:07:55 PM »
Hello everybody...

Just got back from an awesome trip to biketoberfest Daytona :beers:
Today I rode from NC back to PA...About 400mi.
40 miles to my destination, at 120mph (cause i was close, and ached like hell) my bike suddenly lost power...then I reved it again a little (felt like no gas) so I turned on the reserve. No difference. Then I happen look down at my shadow to the left for whatever reason, and see a cloud of exhaust...which would be odd at 70+ mph...so I quickly exit.
Bike sounds like crap, and dies as soon as its stopped. Look down an theres no oil in the window. As smoke or steam comes out from underneath the oil cap, I pour in another quart. Try to fire it up. It fires up, but sounds horrible so I shut er down quick. Get triple A on the phone. Bikes back in PA.
Now, once cold, It wont turn over at all. Sounds like the starter is trying, but just not turning...

Blown motor?
Piston rings?
Gasket somewhere?

Gonna pull the plugs tommarrow morning and see what I see...Will follow up then. Thanks ahead for any ideas and comments...except about riding fast, LOL
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Offline Octane

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Re: Bike lost power, ran very rough, now no start
« Reply #1 on: October 23, 2011, 08:02:51 AM »
Sounds like something has let go in a big way. No longer turning over? Can you turn the engine by hand?
I would hazard a guess that maybe an oil ring has failed or a seal somewhere - pumped the oil out and it has run real low gotten hot and the pistons are starting to pick up.  - or - running that hard you have run so lean that you have burnt a hole in the top of a piston? Sounds nasty whatever it is.
Pull the plugs, try to turn it over by hand - go from there.
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2006 B12 112.5 Mains, adjustable needles (full rich), std pilots 3.75 turns out, K&N, airbox 1.5" mod, Staintune exh.

Offline 400banditman

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Re: Bike lost power, ran very rough, now no start
« Reply #2 on: October 23, 2011, 09:06:17 AM »
Thanks octane...
But how exactly do I 'hand crank' the engine? Leave it in gear and turn the rear wheel?
Are there any resources detailing piston removal/installation? If one needs replaced, may as well do them all while im there...or try to find a used engine to put in...but that aint cheap :(
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Offline 400banditman

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Re: Bike lost power, ran very rough, now no start
« Reply #3 on: October 23, 2011, 03:39:34 PM »
Here are some pics of the carbs and air box...any thoughts?
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Offline canyonbreeze

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Re: Bike lost power, ran very rough, now no start
« Reply #4 on: October 24, 2011, 11:38:59 AM »
The big puddles of oil in 1 & 4 are troubling to say the least.  My 400 redlines at ~105 MPH with stock gearing which is what the manual says it should.  You say you were going 120 MPH?  At what RPM?
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Offline 400banditman

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Re: Bike lost power, ran very rough, now no start
« Reply #5 on: October 24, 2011, 11:43:35 AM »
All stock gearing, verified. At 120 I'm around 12k rpm. But I don't know if It's been jetted, or anything like that.
What's your take on that oil? Blown piston rings? Or something more serious?
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Offline pmackie

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Re: Bike lost power, ran very rough, now no start
« Reply #6 on: October 25, 2011, 04:34:59 AM »
Quote
What's your take on that oil? Blown piston rings? Or something more serious?

Likely something pretty serious. We can only speculate about what went wrong, but worst case is that a valve went through a piston...it's not likely to be a gasket.
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Paul
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Offline 400banditman

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Re: Bike lost power, ran very rough, now no start
« Reply #7 on: October 25, 2011, 07:37:19 AM »
That would be a lot of trouble....though I'm leaning toward blown rings..I will find all this out in the comming days of further disassembly.
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Offline Wrider

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Re: Bike lost power, ran very rough, now no start
« Reply #8 on: October 25, 2011, 01:54:38 PM »
For what it's worth, jetting is not going to affect your limited top speed.

You said the starter motor wants to turn the motor over, but it's not?  Is the engine turning over at all? Or is it just not firing?  If it's not turning over at all, chances are good your motor is seized somehow or another.

As far as the oil in your airbox and carbs... No bueno...  Seems to me your crankcase vent got filled with oil, filled your airbox, went through the carbs, and screwed up your engine.  If you got enough oil in there at one time to screw up the engine, you need a new engine as chances are good your pistons, conrods, head studs, and possibly crank/bearings are done for as well.

Oh and as for turning over the engine by hand.  On the right side there's a little plug in the side case that looks like it's for a huge flat head screwdriver.  Take out that plug (using the biggest flathead you can find, the proper tool is best but most don't have it).  Should be a 14mm bolt in there that you should be able to turn over using a socket and ratchet.
« Last Edit: October 25, 2011, 02:00:32 PM by Wrider »
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Offline 400banditman

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Re: Bike lost power, ran very rough, now no start
« Reply #9 on: October 25, 2011, 01:57:25 PM »
Great...lol well time to tear it all down an find out
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Offline Wrider

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Re: Bike lost power, ran very rough, now no start
« Reply #10 on: October 25, 2011, 02:01:00 PM »
updated original post.  Sorry to hear that happened though man.  Hope it's not what I think it is and it's a whole lot simpler!
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Offline interfuse

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Re: Bike lost power, ran very rough, now no start
« Reply #11 on: October 25, 2011, 07:53:41 PM »
I'd start by clearing the cylinders of oil.

Chances are you're hydrolocked with oil. Remove the sparkplugs and turn the motor over. It's best not to use the starter motor for this or you'll end up with oil on the ceiling. Shift into 6th and push the bike around. If the motor isn't seized then I'd drain he carbs and put everything back together and see if it'll start.

Then you can start to diagnose what's wrong. Its probably cheaper to find another motor and swap then trying to rebuild a mashed motor. But only time will tell...
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Mike

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It's more fun to ride a slow bike fast than a fast bike slow.

Offline 400banditman

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Re: Bike lost power, ran very rough, now no start
« Reply #12 on: October 25, 2011, 07:58:17 PM »
Hey great idea! So if after I drain it begins to turn an crank normal, it may be an indication of....?
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Offline interfuse

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Re: Bike lost power, ran very rough, now no start
« Reply #13 on: October 25, 2011, 08:41:25 PM »
Its an indication that your motors not seized... Lol that's about it. Then you can do a compression test.
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Mike

'91 GSF400
It's more fun to ride a slow bike fast than a fast bike slow.

Offline 400banditman

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Re: Bike lost power, ran very rough, now no start
« Reply #14 on: October 25, 2011, 08:46:47 PM »
What would the compression test be for? If I have to replace two sets of rings may as well do all...found some on ebay used...working out a deal now hopefully. Either way work begins tomorrow. Check back for updates
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