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Old 07-12-2013, 10:48 AM   #16
bdarling
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Quote:
Originally Posted by farmerger View Post
Here is the piston



Jim, pull the piston, is there a JVB pictorial or video on that?
Here is a great writeup from another inmate:
http://www.advrider.com/forums/showthread.php?t=634348

I've been into my left cylinder more times than I care to remember, but it's an easy job. Just be mindful of the timing chain rails when you're sliding the cylinder back on, they can hang up on internal sections of the cylinder casting.

Also, I would advise that you remove that cam chain tensioner before you start wiggling stuff. I'm not sure if the piston has room to come loose with the head disassembled, but you don't want to go fishing for it.

-Blake
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Old 07-12-2013, 10:55 AM   #17
JimVonBaden
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It is a shame you didn't compression test it first, you would then know if the valves were bent.

While it doesn't look too bad, a damaged valve, or cracked piston can seriously ruin your day if it lets go while running, basically putting crap all over your motor.

I would still have them checked.

Jim

PS "a video on this" Ha ha ha, how original!
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Old 07-12-2013, 11:01 AM   #18
Twilight Error
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Originally Posted by JimVonBaden View Post
While it doesn't look too bad, a damaged valve, or cracked piston can seriously ruin your day if it lets go while running, basically putting crap all over your motor.

I would still have them checked.

Jim

PS "a video on this" Ha ha ha, how original!


The valves hit the piston, those parts should be treated as suspect until they're proven okay. Even then, I would probably replace those parts - they're a lot cheaper now than in addition to a lot of other bits when one lets go...
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Old 07-12-2013, 12:17 PM   #19
AntonLargiader
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I have seen plenty of smacked valves on Oilhead motors and none of them involved piston damage (beyond the scarring that you see on the rim of the pocket). However, at this point pulling the cylinder is pretty simple.

Not sure about the cam, but I can't see it too well. I would look at it really close and also the lifter. Furthermore you don't know if the guides got whacked, etc. You have to look at everything.

If you let a shop handle this (if you went the insurance route) they would probably replace the piston since it shows damage. Heck, they might replace the head and nearly everything else, figuring that there may be unseen damage.

Dunno what your deductible is but you're already in for a valve cover, two valves and a head gasket. $350+.
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Old 07-12-2013, 12:43 PM   #20
farmerger OP
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Originally Posted by AntonLargiader View Post
I have seen plenty of smacked valves on Oilhead motors and none of them involved piston damage (beyond the scarring that you see on the rim of the pocket). However, at this point pulling the cylinder is pretty simple.

Not sure about the cam, but I can't see it too well. I would look at it really close and also the lifter. Furthermore you don't know if the guides got whacked, etc. You have to look at everything.

If you let a shop handle this (if you went the insurance route) they would probably replace the piston since it shows damage. Heck, they might replace the head and nearly everything else, figuring that there may be unseen damage.

Dunno what your deductible is but you're already in for a valve cover, two valves and a head gasket. $350+.
Been reading the repair manual and did some quick pricing....holy smokes...BMW says to replace the piston and cylinder as they are a matched pair in size. Also, to get the correct piston you have to pull and weigh the right piston, again the two pistons have to be within 10 grams of each other in weight. Put all this together plus parts (which are of course way more expensive up here in Canuckistan) add in shop labour and I'm looking at upward of $4k I think. The piston cylinder set alone, in US prices, is almost $1200. Time to call the insurance.
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Old 07-12-2013, 02:21 PM   #21
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Or maybe you're just in it for a valve cover, two valves and a head gasket. And a bunch of time.

Only you know if you can assess the condition of the rest of it.
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Old 07-12-2013, 04:14 PM   #22
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too late, but I would have done a differential compression check (leakdown) to see if the valves leak. if that passes, I would manually operate the valves in the head to see that they move ok & don't stick.

then, dial the pushrods to see if they are bent. inspect the chain full length. polish the scrarched looking stuff with fine sandpaper (or not). reassemble, run it, check it

as it is.... I would not worry about the piston in the slightest. get a brush on the piston head & knock off the carbon so you can see. since the head is off... dial the valves to see if they are bent. check the guides for cracks.... especially if they are cast iron... wouldn't worry much if they were bronze.

if you are worried about the cam have someone Magnflux it

if the valves arn't bent to the point where they stick in the guides the damage is negligible
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Old 07-12-2013, 06:10 PM   #23
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Do you plan to keep the bike? If so, I would tear down to the piston and rod (remove the cylinder) for a thorough inspection and satisfy myself that the piston skirt is OK.

If not, a couple of valves, some gaskets, reassemble and sell it.

What is the VIN for your bike?
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Old 07-12-2013, 09:04 PM   #24
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naw.... don't be so paranoid. over the years I've fixed at least half a dozen rigs with interference engines that have dropped the cam chain/belt. I'm driving one now in fact (I got it real cheap because the chain broke)... it bent 4 valves 30 degrees off axis, but the cylinder head was fine. the pistons had little finger nail grooves in the tops, but pistons are pretty tough. check for cracks, buff out the rub marks if they bother you (if there are any.... looks like not) dunno.... I got 25000 miles on this one since the failure. GMC Tracker (Suzuki)... my daily driver
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Old 07-12-2013, 09:12 PM   #25
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naw.... don't be so paranoid. over the years I've fixed at least half a dozen rigs with interference engines that have dropped the cam chain/belt. I'm driving one now in fact (I got it real cheap because the chain broke)... it bent 4 valves 30 degrees off axis, but the cylinder head was fine. the pistons had little finger nail grooves in the tops, but pistons are pretty tough. check for cracks, buff out the rub marks if they bother you (if there are any.... looks like not) dunno.... I got 25000 miles on this one since the failure. GMC Tracker (Suzuki)... my daily driver
I have the remains of four broken valves from a Triumph Speed Triple. The timing chain jumped and broke the valves. All it needed were four new valves.

Then there was the Ducati 999 that lost a collet and dropped a valve. The stem looked like a noodle. A new valve and it was fine.
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Old 07-13-2013, 08:42 AM   #26
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Originally Posted by def View Post
Do you plan to keep the bike? If so, I would tear down to the piston and rod (remove the cylinder) for a thorough inspection and satisfy myself that the piston skirt is OK.

If not, a couple of valves, some gaskets, reassemble and sell it.

What is the VIN for your bike?
Been on the fence on selling it for a while now. It will go up for sale once/if its fixed. If it does get fixed I want the buyer to be confident in buying a solid bike, not a liability. Thanks for all your guys' advice. If I was keeping it I would just put in new valves, a new follower and pushrod and ride.
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