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Author Topic: PLEEEASE HELP, Timing/ pistons  (Read 817 times)

Giggs

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PLEEEASE HELP, Timing/ pistons
« on: August 10, 2017, 04:58:04 PM »

Hey everyone. I've been on here years ago but lost all my login info and like everything else it seems when you need a "send your new password link" to work it doesn't... SO I'm at the point of being ready to throw my once beloved bike to the curb because of a series of my STUPID mistakes and need help getting out of this mess.

STORY:

I accidentally overfilled the oil. Bonehead move. I've never done that before so started assuming the worst. Spoke with a few people and after changing the oil and filter, it still blew smoke and one of those people I spoke with thought it might be a valve gasket. After ordering parts I ripped down the rear piston until just the top of the valves were showing ( removing one crankshaft). Realizing the 2 week wait for parts was a waist of time -as another mechanic said hes sure nothing is wrong I need to ride out the smoke- I tried to put the bike back together. *SNAP* broke a cam cover. Great, another wait and a trip to the USA. After another round of parts and a massive 2 days struggle ( one day putting it back together, it not starting, diagnosing why, tearing it back down, realizing I now need to fit the less-than-perfect newly-acquired (used) cam cover) I got it fitted and lined up the cams 16 pins apart. But lucky me, went to start and it rolled once, I heard a clang like a weird start and a CLUNK. Now it wont start and it is giving me the same symptoms as before. Completely locked up and not pretending to rollover/overpowering the starter. Probably another piston jammed up somewhere.

PROBLEM:

Bike wont start and I have no idea what to do next

NEEDS HELP WITH:

Lining up the pistons I believe but I do not want to start another project until I am sure I am on the right track... very frustrated and what a waist of a summer.

GUIDS:

Parts and service Manual. Of which the service man is very unclear on how to align the magneto.... never done that before either.


PLEEEEEASE help.... thank you.


**UPDATE**

Okay, I've gone back into the engine and am now trying to make completely sure the crankshaft is line up properly.

Service manual says to rotate the magnito 283 degrees counter clockwise until you see an "R" when adjusting the rear camshafts.

**NOTE the manual does NOT tell you the "R" and "F" for rear and front is under a bolt on the magnito cover you are supposed to remove in order to see.... VERY annoying**

Now when I try to move it ( bike is in nutral) it moves basically freely except when at a certain point just before the "R" becomes visible.

QUESTION:

When rotating the magnito, should it be able to spin freely 360 degrees and if it cannot what could possibly be stopping it.

Very frustrating.
« Last Edit: August 11, 2017, 10:34:02 PM by Giggs »
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coffeeholic

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Re: PLEEEASE HELP, Timing/ pistons
« Reply #1 on: August 16, 2017, 05:27:31 PM »

HI just read this and sounds like your valve timing is wrong and a valve is opening or open when the piston is on the rise!
i would check the valve timing as per the service manual. remove the spark plugs to allow you to rotate the engine by hand easier. And yes the engine should rotate freely through 360 degrees without the spark plugs fitted. with spark plugs fitted you would feel resistance on the compression stroke. hope that helps.
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Cloud

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Re: PLEEEASE HELP, Timing/ pistons
« Reply #2 on: August 16, 2017, 07:00:41 PM »


The starter is powerful enough to donk a valve out of shape, too. You can line everything up as per timing marks, and hope for the best, or you can tear the engine down again and take a look to see if the valves are bent. Also worth checking that the cylinder head isn't damaged, or that valve stem guides/seals or collets aren't mashed. It's unlikely but takes two minutes to check once you've got the cylinder head in bits, so you might as well.

The way to avoid this in future is to turn the crankshaft gently by hand/socket bar.

Now that you've found the bolt on the magneto rotor cover, timing is going to be pretty simple. There's also a thing on the side of the magneto rotor cover that you can unscrew which will let you wind the crankshaft around using a (19mm?) socket.

If the magneto rotor is locking solid, that'll be your piston kissing your valves. It doesn't rotate freely, but it can be spun by hand, with resistance coming from valve springs, and, if you've left spark plugs in, the engine compression.

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mrcrum

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Re: PLEEEASE HELP, Timing/ pistons
« Reply #3 on: August 16, 2017, 07:54:57 PM »

It probably is your timing and a valve is hitting the piston as coffee said.  When it binds is one of the cams pushing a valve down?  If so, you should start over.  Remove the timing chain tensioners, remove the cams, place a piece of pipe or something across the top of the heads to hold the timing chains up so they wont fall into the crank case but will still allow you to turn the flywheel.  Set the flywheel to F, install the front cams with the stamps in the gears in the right position as per the manual.  Then turn 285 degrees counter clockwise to R and install the rear cams.  Another thing that can cause this that I experienced is that if a timing chain isnt tensioned enough it can cause the chain to bind when turning counter clockwise but not clockwise due to the arrangement of the chain glides.
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albertinhouston

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Re: PLEEEASE HELP, Timing/ pistons
« Reply #4 on: August 17, 2017, 04:42:48 PM »

clockwise or counter clockwise?
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mrcrum

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Re: PLEEEASE HELP, Timing/ pistons
« Reply #5 on: August 17, 2017, 11:51:35 PM »

Counter clockwise.  You set the front cams with the mark on "F".  That establishes that tdc as the first tdc.  If you look at the flywheel you'll see the "R" mark to the left of the "F" mark.  You turn the flywheel counter clockwise so that it goes less than a full revolution to reach the "R" mark on the flywheel.  Then you set the rear cams.
« Last Edit: August 18, 2017, 12:32:32 AM by mrcrum »
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albertinhouston

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Re: PLEEEASE HELP, Timing/ pistons
« Reply #6 on: August 20, 2017, 04:52:48 PM »

Im guessing u slipped up and left off counter before
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umop-ǝpisdn

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Re: PLEEEASE HELP, Timing/ pistons
« Reply #7 on: August 20, 2017, 11:40:38 PM »

How did you count your links? Is the first link zero, or one?
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Giggs

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Re: PLEEEASE HELP, Timing/ pistons
« Reply #8 on: August 31, 2017, 05:34:09 AM »

Everyone!

Thank so all so much for your information. It was completely correct. I removed the Cylinder head and my stomach sank and was completely defeated when I sat that not only was there in fact a massive timing issue which lead to my piston and Valves kissing, but it was bad enough that one attempt top start broke off two of the valve heads, one spun over and drove a hole RIGHT through the piston head.

I was a little relieved when days later it dawned on me that I can replace the piston head without a complete tear-down of the engine BUT its been a waist of a summer and I'm super bummed having to wait for parts...

SO, at this point for those who would like to see the bummer-of-a-journey through I ask this:

In the name of saving time and a little money ( I live in Ottawa Canada and the only Hyosung dealer is BRUTAL to say the least... like just awful), would you guys buy and wait for/replace the piston rings while I have the new piston out or would I be able to get away with using the original ones them knowing the front piston ( along with ITS rings) is untouched and will be ageing at the same time?

and

Would I be able to use the same valve keepers, seals etc or should I replace all of them as-well as the bent/broken valves themselves?

Thanks everyone... this has sucked for riding this year but you guys are making it suck much less.
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umop-ǝpisdn

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Re: PLEEEASE HELP, Timing/ pistons
« Reply #9 on: August 31, 2017, 11:06:08 AM »

Why are you buying parts from the local dealer? Is pain your 'thing', is it?

whygostock.com <-- USA based
hyosungwholesale.com <-- Korean
hyosungsource.com <-- Korean
koreanbikeparts.com <-- Korean
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