Author Topic: Tappet Troubles (Read 2274 times)

the technological J · « **on:** April 06, 2010, 10:14:32 pm »

so i went to do my clearances the other day only to find the lock nut was missing on the number 3 intake..... i figured this thing has already worked it way down to the sump considering it wasnt up top... dumb move im sure but the thread was messed up on it so i just replaced the adjuster and put in one off my 73 parts engine....... and did all my clearances tightened down the lock nuts out the covers back on started it back up and listened very very carefully and since it didnt make any noise figured it was safe to take for a ride about 15 miles away it starts tapping...... so i was headed home any way i figured i would check it out after it cooled down,,,so i got to her after i got home from work started pulling the tappet covers only find that not only was the lock nut missing but the whole tappet adjuster..... so im planning to pull the oil pan... hoping to find them down there... but what could cause this? did i just happen to not tighten this lock nut down enough..... what do u all suggest?

shorterdanny · « **Reply #1 on:** April 06, 2010, 11:35:45 pm »

bad stuff mate that could had been real nasty,

have you noticed any extra vibration? is there excess oil in the tappet area?

although mine often shakes like an old tumble drier and nothing has come loose yet.

Can't really think of anything else, very strange, a mild loctite would prob stop anything else coming loose, as long as you can still adjust when required.

bucky katt · « **Reply #2 on:** April 06, 2010, 11:47:19 pm »

could the rocker arm be cracked at the end, allowing the tappet adjuster to back out easily? seems like with the thin material at the ends there might be crack prone. i wouldnt use loctite there if it were mine. not necessary when there is a locknut involved.

the technological J · « **Reply #3 on:** April 07, 2010, 07:02:57 am »

yeah the bike does need the carbs synched it vibrates pretty good.... but i just discovered i also have an airleak to remidey i'll check for a crack on the end... i have school all day so i wont get a chance to play with her till later this afternoon

the technological J · « **Reply #4 on:** April 08, 2010, 07:52:04 am »

against my better judgement i just threw on an andjuster and a lock nut did the clearances and tightened down the lock nut.. i mean really tightened it down(almost stripped it) i even laughed at myself and said thats not gonna move so i took her for a ride about ten miles away i stopped at my buddy's place long enough for the bike to cool down a little bit... on the first mile of the ride home theres that chatter again..... what in the world could cause this?i know i have an air leak... that couldnt be connected some how right?

i checked no crack in threaded part of the rocker arm

NickC · « **Reply #5 on:** April 08, 2010, 08:04:49 am »

I had the same thing happen to mine, opened the cover and the nut had fallen off. It was still in the chamber though, so I fished it out. It seems like it would have a tough time going up and over the rocker arm shaft, and work its way to the center of the head, then fall down into the sump.
Have you really inspected in the space where the rocker arms are to see if its in there?

Duke McDukiedook · « **Reply #6 on:** April 08, 2010, 08:12:04 am »

Yeah, if that happened I think your motor would be pretty knackered.

bistromath · « **Reply #7 on:** April 08, 2010, 08:22:46 am »

Hate to say this, but you really sound like you're asking for trouble. If any one of the now-loose parts works its way into something moving, it's very likely the end of your motor. Why would you run it again, after losing two lock nuts and a valve adjuster, and knowing they're rattling around in there somewhere?

My guess is the rocker arm is stripped out and keeping the lock nut from providing tension. Replace the rocker arm, pull the bits out of the sump or the head, and stop playing Russian roulette with your engine.

Duke McDukiedook · « **Reply #8 on:** April 08, 2010, 08:29:30 am »

+1, Bistro is right.

You do need to recover those parts before you run the engine again, I know, total bummer.

killerdwarf · « **Reply #9 on:** April 08, 2010, 09:03:44 am »

You ride around with fasteners hopefully in the sump of your engine, and air leaks to boot?

Rampage1967 · « **Reply #10 on:** April 08, 2010, 09:35:52 am »

I would suggest replacing the rocker arm & finding those adjuster parts before you run that engine again.
I had this happen on a CB360 once. It only bent one valve & broke the cam chain when the nut passed through the cam chain & sprocket. Is that a chance you want to take with your 750???

Frostyboy · « **Reply #11 on:** April 08, 2010, 07:36:00 pm »

I really have no clue, but is it possible that the rocker &/or the shaft is worn to the point where the adjuster isn't sitting flush on the top of the valve?

Maybe if it's working on the outside edge of the adjusting screw, it's got enough force there to actually turn the screw out as it's working?

Like I said, just guessing. I look forward to the solution though.

the technological J · « **Reply #12 on:** April 09, 2010, 07:40:13 am »

do i have to pull the engine to remove the valve cover? does any body know of a cheap source for that gasket.... if i find the missing parts in the sump could i retap the holder with some thing bigger?

Duke McDukiedook · « **Reply #13 on:** April 09, 2010, 07:48:15 am »

750? Alas, you must pull the engine to do that.

I think you can buy a Honda cover gasket separately, not cheap but cheaper than a gasket set.

the technological J · « **Reply #14 on:** April 10, 2010, 10:03:50 pm »

if i can find a half thickness locknut for under the tappet as well as the normal lock nut for on the top would this be an ok substitute for replacing the rocker arm? so in theory the (presumably) stripped rocker arm would have nowhere to go? all this assuming i find the missing parts in the sump... and fix the air leak... what would cause an air leak to get worse as the engine heats up? the engine revs and returns to normal when the engine is cold but the leak gets worse when shes good and hot?
if i have to replace the rocker arm is it safe to replace this gasket with a generic cut out cork gasket?

the technological J · « **Reply #15 on:** April 11, 2010, 10:37:21 am »

really? nothing?

NickC · « **Reply #16 on:** April 11, 2010, 10:44:06 am »

Which gasket? the tappet cover or the valve cover?

TwoTired · « **Reply #17 on:** April 11, 2010, 11:08:37 am »

Take a look at the top of the valve stem where the adjuster makes contact. Is is flat? Pitted? Concave? Mushroomed?

the technological J · « **Reply #18 on:** April 11, 2010, 08:56:38 pm »

Quote from: TwoTired on April 11, 2010, 11:08:37 am

Take a look at the top of the valve stem where the adjuster makes contact. Is is flat? Pitted? Concave? Mushroomed?

i dont think i like where this is going

bryanj · « **Reply #19 on:** April 11, 2010, 11:36:02 pm »

No you cant use a cork cut out gasket

To do it right the engine comes out

If you dont do it right it WILL go bang big time and probably throw you down the road

Just cos its an old bike it dont mean you can cheapskate the repairs!!!

the technological J · « **Reply #20 on:** April 12, 2010, 11:34:51 am »

im going to check it out tonight im hopeing i dont need a valve job im trying to figure out if theres some thing i can do to just hold one of those adjusters in place.... if the valve stem looks ok can i try the double lock nut approach? im broke and desperate to get this out on the road. so i need some creative thinking that wont result in a large bang

Whaleman · « **Reply #21 on:** April 12, 2010, 11:40:31 am »

I have extra rocker arms. If the threads on the adjuster are good then something must be wrong with the rocker. Dan

the technological J · « **Reply #22 on:** April 12, 2010, 11:45:06 am »

Quote from: Frostyboy on April 08, 2010, 07:36:00 pm

Maybe if it's working on the outside edge of the adjusting screw, it's got enough force there to actually turn the screw out as it's working?

this is what im afraid of and in this case it wouldnt be the rocker or the tappet adjuster... i also have a dismantled spare engine..... i f absolute worse comes to wrse i got a head i can get the valve gone over and maybe even port the heads

the technological J · « **Reply #23 on:** April 12, 2010, 05:21:58 pm »

unbelievable! i pulled the tappet covers and the freaking number four intake lock nut was missing.... im gonna have to go around and tighten them all down this is absurd

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Author Topic: Tappet Troubles (Read 2274 times)

Rampage1967