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Old 10-08-2013, 03:16 PM   #16
Sumi
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Quote:
Originally Posted by borborygmus View Post
Is it possible to skip the chain on the cam gears if you start the engine with the throttle open(flooded) and the hydraulic tensioner does not have a stiffie yet? I know the "what" now just trying to figure out the "why". And also does anybody have a line on valves or do stick with OEM?
I've never had it happen on my friends (3 of them on lc8s) or my bike, and I can tell you all of them bikes tend to lay a lot on their sidesD But.. ofcourse it might happen..
Don't want to ruin your day, but as you probably already know, it seems like you will have to pull at least the head to see what's going on:(

Btw, is the spark plug/coil OK? (swap it between the cyls? maybe..)
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Old 10-08-2013, 03:39 PM   #17
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I did not think a need to, after the leak down test was positive. I also poured alchohol into the intake ports then compressed air into the cylinder=lots of bubbling, lots of air comming from the cylinder up thu the valves.
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Old 10-08-2013, 06:00 PM   #18
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Unless your cam chain is totally shot - so stretched that it rattles all the time - it can't skip. Even if you pull the tensioner out, you can't get it to skip.

You've bent or burnt a valve.
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Old 10-08-2013, 08:13 PM   #19
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My money is on a bent valve. If you have enough fluid in the cylinder and try to turn the engine and compress the fluid, if the valves try to open at the same time there can be so much pressure that there literally isn't anywhere for things to go, resulting in excess pressure on the valve stem, usually causing it to bend. If it was broken, you'd hear bits of valve grinding away in your engine, usually.

If it's flooded really bad, you can often put the bike in 6th and push it backwards to try to blow things out. Due to valve overlap and rotational speed, this is often more effective than using the starter if things are really bad.
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Old 10-08-2013, 09:54 PM   #20
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I do not think it was flooded enough to fill the cylinder. I appreciate Zuber's enthusiasm for the burnt valve theory. Good to know it is that hard to skip a tooth on the cam chain. FYI the 950 has 21k miles. I am the 2nd owner and when I got it I immediately adjusted the valves and found the intakes very, very tight. I just do not want to replace the valves with out having a good feeling it is not going to happen again. weird thing is I put 2000 miles on it after adjusting the valves and then ........heads are coming off tomorrow.
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Old 10-09-2013, 01:34 AM   #21
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IMO at TDC the marks (circle at the base of the teeth on the cams (see picture below) at the front cyls) on the cams should line up with the heads surface, so if you rotate the engine to TDC, and the marks on the cams are lined up there correctly, then it didn't skip a tooth. The front cam lobes should be pointing away from each other at TDC.

If they don't line up at TDC, I think you can just pull the bridge (!!!make sure the valve springs are not puting a load on it (there should be a gap between the buckets and the lobes - this is btw the gap that you adjust at a valve adjustment)!!!*, or it will crack - and because they're paired with the head, it's an expensive lesson), and reset the cams.. Instead of my first post in the thread I think there is no need for a degree wheel to perform this.

* Hope you haven't made any damage to it when you did the leakdown test - as you wrote in post #13 that you have loosened the bridge and turned over the engine that way.. BTW if the leakdown test says that it won't hold any PSI, then apart from the cams position to the crank, there is something else wrong in there:(

there are some good thoughts on this link:

http://www.ktm950.info/how/Orange%20...ve_adjust.html

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Old 10-09-2013, 02:59 PM   #22
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The chamber on these is tiny,, you can hydro lock a cylinder with a very tiny amount of fuel. I found a reference at one point that its less than 10CC to do things in..

Good Luck!

PS: Use the Rotax valves they are top notch..

Dave
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Old 10-09-2013, 10:12 PM   #23
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Quote:
Originally Posted by borborygmus View Post

I am the 2nd owner and when I got it I immediately adjusted the valves and found the intakes very, very tight.
Ahhh, the pages of inquiry slowly reveal.... You may have a burned valve, not just due to this tip over, but from them being run with no clearance. You may have been the first person to check the valve clearance.

Keep us in the loop when you pull it down. Check the cam timing on the way in.
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Old 10-10-2013, 12:10 PM   #24
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does anybody know the trick to remove the cam chain from the top cam gear so that the head can be removed. Does not seem to b e enough room between the gear and the side of the casting on the cylinder head.
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Old 10-10-2013, 12:24 PM   #25
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never mind, you feed the cam chain of towards the center of the engine. And the gear comes strait up! ef me with a shoe
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Old 10-10-2013, 11:40 PM   #26
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Quote:
Originally Posted by borborygmus View Post
never mind, you feed the cam chain of towards the center of the engine. And the gear comes strait up! ef me with a shoe
haha:)

Don't forget to post pictures!:)
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Old 10-13-2013, 03:18 PM   #27
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Took head to cycle machine shop(very reputable) and the intake valves are wore out. 21,000 miles and the valves are so far into the seats there is not a lot of sealing surface left. Anybody from H.O.W. reading this, have you ever heard of such a thing?

borborygmus screwed with this post 10-14-2013 at 08:51 PM
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Old 10-17-2013, 12:29 AM   #28
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I've seen that on lots of motors, when the proper clearance wasn't kept. Normal result for tight valves.

May you serve, at least, as a bad example for others. (sorry)
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Old 10-19-2013, 03:18 PM   #29
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actually I bought the bike used and put in the truck, brought it home and immediately tore it down for a valve adjust. BTW you don't need to turn the motor over for a leak down test, so it is safe to loosen the cam towers.(provided it is at tdc) Unfortunately the lesson to learn here is: when you buy a used bike, (even though from an inmate) it may not have gotten proper maintenance.
I appreciate the feed back from you guys, it was very helpful. The worst part of a diagnose and fix is not riding the bike especially during perfect weather!
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Old 10-19-2013, 09:33 PM   #30
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How do you do a leak down without having all the valves closed and to do that on both cylinders, you'd have to turn the motor? You got me curious.. :)

BTW I use air through the sparkplug hole and a leakdown guage..

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