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Thread: After valve adj engine wont turn over

  1. #1
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    After valve adj engine wont turn over

    Got a /5 about 2 months ago and it was running a little rough, mainly it would stall out when stopping if I wasnt rolling on the throttle a little. SO I decided to perform a valve and timing adj at the suggestion of my mechanic.

    1. I unplugged the neg lead from the battery.
    2. Then I took off the valve covers
    3. Torqed the 6 nuts to 29 ft/lb- I think that it was it said in the Clymer manual- whatever that said...
    4. Ready to do valve adj so I took off engine cover.
    5. Insterted 6mm allen wrench to rotate the engine, found the OT in the window or TDC.
    6. Inserted feeler gage and adjusted exh to 0.008" and the intake to 0.004". (There are also two other sources that said to adj to the intake to .006, and the other said that both intake and exh are supposed to be .004"
    7. Did adj on the other side and reversed to put everything back together.

    Started the bike and it started coughed and stalled; I tried it again and this is when I started to here more noise in the valve heads and the engine wouldnt turn over. The starter was going (I have /6 trans) but the engine wasnt turning over.

    So I did the valve adj all over again making sure everything was in the correct places, rocker arms ok (very small vertical movement like suggested), but when I went to turn over the engine by hand with the allen wrench I noticed that it wasnt turning the engine over... the nut was loose so I tightened it and then I was able to turn the engine over to find OT. I thought that was weird.

    Tried to start the bike again wouldnt turn over with the elec starter on the /6 tranny. In case it is the battery I will place it on a trickle charger once I get done posting.

    SO I am looking at the bike not turning over but the starter def doings it thing; and the one instance of the nut being loose when going to rotate the engine by hand. Does the problem lie within that loose nut?

    Thanks for your help! Sorry if I went on in detail but I am frustrated and wanted to make sure I got everything down.

  2. #2
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    I read through your post a couple of times and I'm confused. When you found the "OT" mark on the flywheel, did you verify the cylinder you were adjusting was on the compression stroke? Only one side is on the compression stroke at a time, the other side will be 360 degrees off (or one revolution of the flywheel). What 6mm bolt were you turning on the front of the engine? When you say the starter was doing it's thing but the engine wasn't turning over, do you mean the starter wasn't engaging the flywheel? Try to give a better description of what you did and what's going on and I and others will chime in and help you get this sorted out. If you adjusted the valves on BOTH sides while only finding the "OT" once, you have one side so far out of adjustment all it's likely to do is spit and sputter. Not to worry, help is here. Start all over and describe exactly what you did.

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    Last edited by mikeb921; 03-09-2008 at 09:45 AM. Reason: Stupidity

  3. #3
    mrich12000
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    Oops

    Posible valve open when you ajusted the wrong side?
    Last edited by mrich12000; 03-11-2008 at 02:58 AM.

  4. #4
    Liaison 20774's Avatar
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    Others have mentioned that you probably didn't set one side while on the compression stroke. I have a few other suggestions, mostly which counter the Clymers. Some suggest using the Clymers to light a fire so you can see what you're doing when you repair your bike!!

    29 ft-lbs is probably a bit much for the cylinder studs. That's putting additional pressure on the threads in the engine case and there's a danger, over time, of pulling them out. Next time, I suggest going to only 25 or so.

    Turning the engine using the allen wrench in the alternator bolt is probably OK if you remove the spark plugs. Turning against the compression with this small bolt will eventually lead to rounding out the allen bolt. I've been putting the tranny in 4th or 5th gear and then turn the rear wheel while watching the valve action on the left cylinder. When I see the intake valve open and then close, I know that cylinder is on the compression stroke. I then reposition myself on the left side of the bike and then bump the rear wheel with my hand, watching for the F mark, the S mark, and finally sneak up on the OT mark. Set the valves. Rotate the engine 360 degrees or so that OT mark reappears the next time. Set the valves on the right side. Rotate the engine two more 360 degree rotations and check your work.

    HTH...
    Kurt -- Forum Liaison ---> Resources and Links Thread <---
    '78 R100/7 & '69 R69S & '52 R25/2
    mine-ineye-deatheah-pielayah-jooa-kalayus. oolah-minane-hay-meeriah-kal-oyus-algay-a-thaykin', buddy!

  5. #5
    I will also add to the suggestion that one side was adjusted while not on the compression stroke... unless you left that part out of what you did. You should get the bike to "OT", find the side with the "loose" (you can spin them by hand) pushrods, adjust the valves, then rotate the engine to "OT" again and adjust the other side - verify the pushrods are loose in case you went too far.

    As for the bolt you're using to crank the engine over, I've had one come loose, as well. I was adjusting valves for a friend and it came loose. Really scared the heck out of me. It's not a huge deal as long as you tighten in back up. I know there is a risk of rounding it out if you're not careful, but I never had much luck rotating the engine with the rear wheel; I always went past "OT". Possibly a combination of the two would be good; rotate with the rear wheel until you're close to "OT", then zero in with the alternator bolt.

  6. #6
    Registered User boxerkuh's Avatar
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    Did you remove the spark plugs? Well, you need to. I found that putting the bike in 5th gear in my case is much easier than messing around with the front cover. When you get up this morning and after you had your morning cup of coffee, I would go do it again, this time with rear wheel. I also do my valves a tight 9 exhaust and a tight 7 intake. Check your plugs to see what they look like to see what your carbs are doing... the head nuts should be tightened to 11lbs, 18lbs, and 25lbs; but when you loosen them, not more than 1/4 rotation, otherwise you break the seal...hope that all makes sense... Good luck.
    Keep the rubber side down!!
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  7. #7
    Liaison 20774's Avatar
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    Quote Originally Posted by jdmetzger View Post
    ...but I never had much luck rotating the engine with the rear wheel; I always went past "OT".
    Yes, that can happen. I straddle the rear wheel and pull the tire through while watching the valves. Once the intake valve closes, I then sit down by the timing hole and use my hand to "pop" the wheel around, nudging the engine rotation a little bit at a time. When I begin to see the F mark, my "pops" get softer, and softer still when I see the S mark. I find it quite easy to nail the OT mark using this method.
    Kurt -- Forum Liaison ---> Resources and Links Thread <---
    '78 R100/7 & '69 R69S & '52 R25/2
    mine-ineye-deatheah-pielayah-jooa-kalayus. oolah-minane-hay-meeriah-kal-oyus-algay-a-thaykin', buddy!

  8. #8
    mrich12000
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    Exclamation careful

    Boxerkuh Is right, you may have a bad neadle & seat posible fuel loaded up and caused hydrstatic lock. If so cafully empty the cyl with no ignition sources. I have had this done to me and it ain't pritty when the starter is pushed. whooosh and fuel everywhere..

  9. #9
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    Quote Originally Posted by Boxerkuh View Post
    Did you remove the spark plugs? Well, you need to. I found that putting the bike in 5th gear in my case is much easier than messing around with the front cover. When you get up this morning and after you had your morning cup of coffee, I would go do it again, this time with rear wheel. I also do my valves a tight 9 exhaust and a tight 7 intake. Check your plugs to see what they look like to see what your carbs are doing... the head nuts should be tightened to 11lbs, 18lbs, and 25lbs; but when you loosen them, not more than 1/4 rotation, otherwise you break the seal...hope that all makes sense... Good luck.

    Hey Guys... so I slept on it.

    Yes I did do both sides by finding the OT mark twice... I knew which side to do because I could turn the pushrods. I also did take out the spark plugs- I hear it makes it a heck of a lot easier to turn the engine that way!!

    So the 6 head nuts should each be tightened to 11 lbs then 18 lbs then 25 lbs after losening the one nut at a time 1/4 turn?

    What am I to check the carbs for? They were fine (as far as I could tell) before doing the valve adj- but what can I check on them? (After doing the valve adj I was going to tighten each carb until it lightly sets and then gradually ease it out until the engine sounds right and then do it for the other carb- but I am not there yet)

    If the flywheel is not engaging- can I check that by leaving the front engine cover off while hitting the starter? Is that safe? I know I have to disconnect battery before that first.

    Spark plugs are a bit blackened (meaning oil is fouling them ) at the very tips but gaps still ok... I should replace those I guess for sure.

    The rocker arms- they are supposed to have slight veritcal play right?

    When at TDC- how are the pushrods centered in the hole? My other source says that the pushrods should be slightly above center in the hole. (http://w6rec.com/duane/bmw/valve/index.htm) There are some pics of the person doing the valve adj.
    When you have the spacing between the valve and arm- are you supposed to push the pushrod in to ensure it is in place and there will be no movement in and out of the pushrod when that side is at TDC. Refer to 12, 13 and 14 of the link.

    I appreciate all the help but I am at a loss right now and in the mercy of your hands and wisedom! Once this gets running I will dedicate the first ride to the beemerheads who helped me out!!!

  10. #10
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    Quote Originally Posted by mrich12000 View Post
    Posible valve open when you ajusted the wrong side?
    This picture in motion rocks. I could just sit here and watch it all day!

  11. #11
    Focused kbasa's Avatar
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    How much did you have to back the adjusters out to get them to clearance spec? I suspect you adjusted the wrong sides at the wrong time.

    Whether you can turn the pushrods isn't the test, whether there's any slop in the valvetrain is. To test for the right side to adjust, you should be able to move the rocker arm back and forth a slight amount. The other side will be completely tight and you won't have any slop in it.

    Now, you've got a bit of a problem in that you'll need to figure out which side is which. I would rotate the engine until one side is tight and adjust that side, then go to the other and do that one.

    Your carbs aren't your problem, your ignition system isn't your problem. To quote one of Eilenberger's Laws - go to where you last touched it. That's where your problem is.
    Dave Swider
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  12. #12
    When I adjust valves, I remove only one valve cover at a time - that way I won't forget which cylinder I'm doing if the job is interrupted. I then turn over the engine using the rear wheel until I see the intake valve coming up - this absolutely means I'm approaching TDC for that cylinder. Using small bumps of the rear wheel it's very easy to get OT without overshooting. If I overshoot, I go back enough to compensate for slack in a worn timing chain, and repeat the small bumps to TDC. You don't have to remove the spark plugs if you're patient and wait for the compression to dissipate between each bump of the rear wheel. A hint to prevent nuts and washers from falling into the drip pan: remove the 10mm nuts and wavy washers first, then put the drip pan under the cylinder and remove the center nut. It should stay in the socket when you remove it. Remove the rocker cover, holding a finger over the end of the center stud to prevent the washer from falling into the drip pan.

  13. #13
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    Quote Originally Posted by KBasa View Post
    How much did you have to back the adjusters out to get them to clearance spec? I suspect you adjusted the wrong sides at the wrong time.

    Whether you can turn the pushrods isn't the test, whether there's any slop in the valvetrain is. To test for the right side to adjust, you should be able to move the rocker arm back and forth a slight amount. The other side will be completely tight and you won't have any slop in it.

    Now, you've got a bit of a problem in that you'll need to figure out which side is which. I would rotate the engine until one side is tight and adjust that side, then go to the other and do that one.

    Your carbs aren't your problem, your ignition system isn't your problem. To quote one of Eilenberger's Laws - go to where you last touched it. That's where your problem is.
    Thanks KB! I didnt want to touch the carbs frankly because they were working before I did the adj- so the problem must be in the adj.

    The way that I did the valve adj was I located the OT at TDC- then I rocked the crankshaft back and forth via the 6mm allen wrench. I noticed that on one side the rocker arms were moving slightly when I rocked teh crankshaft- the side that the rocker arms dont move is the side that I did first. Then rotated the engine found the other OT and rocked it back and forth to make sure the rocker arms were satationary and that is the side that I wanted to do next.

    Now my mechanic said that the rocker arms should have some vertical play as does the clymer manual but this other source says there should be NO vertical play not even the slightest bit.

    Refer to paragraph 9 for discussion on rocker arms... Should there be any vertical play? 2 sources say yes one says no

  14. #14
    Liaison 20774's Avatar
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    Quote Originally Posted by andrewdell19 View Post
    Now my mechanic said that the rocker arms should have some vertical play as does the clymer manual but this other source says there should be NO vertical play not even the slightest bit.

    Refer to paragraph 9 for discussion on rocker arms... Should there be any vertical play? 2 sources say yes one says no
    There is very little freeplay...you should see the oil film moving back and forth as you attempt to move the rocker up and down. Some people try to measure it but you just want to see the oil film moving in and out. If I had to guess, I'd say it was 0.002" or maybe even less...

    As R60US and I said, you really don't need to rock the engine back and forth and worry if the pushrods spin or the rockers move, etc... As you turn the engine and the intake valve first opens and then closes, you're approaching TDC on the compression stroke for that cylinder. Then just slowly continue rotation until you find the OT mark. You'll be where you need to be. If you're not sure, try removing both spark plugs and put your thumb over the hole. When you feel backpressue on your thumb, you're on the compression stroke. Continue rotation until you see the OT mark.
    Kurt -- Forum Liaison ---> Resources and Links Thread <---
    '78 R100/7 & '69 R69S & '52 R25/2
    mine-ineye-deatheah-pielayah-jooa-kalayus. oolah-minane-hay-meeriah-kal-oyus-algay-a-thaykin', buddy!

  15. #15
    Rally Rat
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    I still think you made a mistake on at least one side. If you want to send me a PM with your phone number, I'll try and help you work through this. The fouled plugs aren't helping either, but if it ran before your adjustments it should be running now unless you made a mistake. You're getting the advice you need here, but a real conversation may get you back on track.

    Ride Safe
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