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Pulling cams and timing - whats all the hubbub??

  1. #1
    Member k1200s's Avatar
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    Pulling cams and timing - whats all the hubbub??


    Just got a new DRZ400 and pulled the cams to adjust valves (first time actually in a motor). Why does everyone make it sound so difficult to put this back together? On my bike I just line up a timing marker on the crank, then set one cam to "3" and the other to "2" with the timing markers even with the head. Slip the chain back on and its done... maybe 5 mins max? I still haven't put mine back together since I'm waiting on shims but not sure what the problem would be. Seems really simple and as long as you don't half ass it and try running it without triple checking, rather hard to mess up. Do most engines not have timing markers? Couldn't you just set to TDC and etch your own? I'm just wondering why this is considered more difficult and if I'm going to run into issues, or is it really as easy as it seems. It is a super easy bike to work on so that may be a factor

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  2. #2
    Soul Rider Paul_E_D's Avatar
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    Re: Pulling cams and timing - whats all the hubbub??

    On most bikes, just accessing the cams is an hour's work. But it can be trickier than it seems to get it re-assembled correctly. Often, when you actually seat everything the marks are just off one way or the other, making you second guess yourself. But single cylinder dirtbikes are as easy as it gets.

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    Paul_E_D


  3. #3
    Member k1200s's Avatar
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    Re: Pulling cams and timing - whats all the hubbub??

    Quote Originally Posted by Paul_E_D View Post
    On most bikes, just accessing the cams is an hour's work. But it can be trickier than it seems to get it re-assembled correctly. Often, when you actually seat everything the marks are just off one way or the other, making you second guess yourself. But single cylinder dirtbikes are as easy as it gets.
    Ok yeah I figured that was the case. Just curious, would being off 1 gear on both cams make that big of a difference? I imagine on a real high strung high compression bike it would, but how about like my DR?

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  4. #4
    Soul Rider Paul_E_D's Avatar
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    Re: Pulling cams and timing - whats all the hubbub??

    1 tooth off would definitely cause running issues In some cases that is enough for interference between valve and piston, in others it simply wreaks havoc on timing. One tooth on the cam gear is many degrees of timing difference.

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  5. #5
    Burns retinas nhbubba's Avatar
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    Re: Pulling cams and timing - whats all the hubbub??

    Yes, 1 tooth off is bad news. That induces some stress for me when doing the work.
    I also stress over dropping the chain down the galley, getting the chain unhooked from the crank and not being able to re-hook it, aligning the cams wrong, putting the cams back in the wrong spots and a host of other things one stresses over.

    Then there's just the pain in the ass of getting stuff in and out.

    I once had a Bandit 1200 that required removing most of the back of the motorcycle so you could shift the airbox back so you could get the carb rack out so you could remove the cam cover. 1200cc motor jammed in a double cradle steel frame with very tight tolerances. I usually just forced the carb rack out by forcing it past the intake boots with the aid of a screwdriver. But every time I did so I knew I risked tearing one.

    In the SV you do everything once and then do it all over again for the other jug. Guy before me on my last one neglected to rotate the crank before setting the timing for the rear after setting the front. Bike ran, but weird. Idled just funny. Had okay power off the line, then fell on its face, only to come back a bit just before redline. My friend called it a "big bang SV".

    I had a DRZ. Never had the pleasure of making adjustments. But I recall pulling the cover to check was not exactly trivial. I seem to remember pulling the tank and carb just to get better access. I do remember arguing with the carb once or twice.

    Or maybe its just that my meat hooks are larger than intended for motorcycle work..

    Easiest valve adjustments I've ever done was on my old CB400. Cover came off easily without removing the tank. Screw and nut type adjusters, done with the cam in place. Flat-head screwdriver, a set of craftsman combination wrenches and some feelers and you were done.

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  6. #6
    Lifer gixxer72's Avatar
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    Re: Pulling cams and timing - whats all the hubbub??

    Quote Originally Posted by nhbubba View Post
    I once had a Bandit 1200 that required removing most of the back of the motorcycle so you could shift the airbox back so you could get the carb rack out so you could remove the cam cover. 1200cc motor jammed in a double cradle steel frame with very tight tolerances. I usually just forced the carb rack out by forcing it past the intake boots with the aid of a screwdriver. But every time I did so I knew I risked tearing one.
    All of my carb'd gsxr's were like that. It was such a pain in the ass to remove all the shit to get the valve cover off. At least they had threaded adjusters so the cams didn't have to come out - not that it would have been a big deal at that point.

    I had a 7/11 for a couple years that had all the same level of shit to remove (minus the airbox), but the 1100 motor was so tight in the frame you couldn't get the valve cover off without dropping the front engine mounts and rotating it to make some clearance. Fun times, never again.

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  7. #7
    TWINS! xrocket21's Avatar
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    Re: Pulling cams and timing - whats all the hubbub??

    My ATK was a dream with that offset spine, that fucking bike was made to be easy to work on, I loved it. Pull the tank and 4 bolts and the top was off.

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  8. #8
    Member k1200s's Avatar
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    Re: Pulling cams and timing - whats all the hubbub??

    Yeah, I have women's hands (its a blessing and a curse) so to get to the valves its just pull the tank and that's it aside from the 3 bolts to pull the cover. Dropping new shims in now, if I was off one tooth, how would I know before the engine explodes, especially if the valves don't interfere w/ the piston?

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  9. #9
    Your Father csmutty's Avatar
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    Re: Pulling cams and timing - whats all the hubbub??

    Quote Originally Posted by k1200s View Post
    Yeah, I have women's hands (its a blessing and a curse) so to get to the valves its just pull the tank and that's it aside from the 3 bolts to pull the cover. Dropping new shims in now, if I was off one tooth, how would I know before the engine explodes, especially if the valves don't interfere w/ the piston?
    Timing marks.

    Always verify the marks after you put the cam chain tensioner back in. I always take a picture of the cams and markings before I take it apart. That way I can see the number of teeth between the markings on the cams and the position relative to what it is after.

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    -Christian LRRS/CCS HasBeen ECK Racing
    2011 Pit Bike Race CHAMPION!

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