Topic: Valves adjusted,can of nuts

[bikerbart]

So after retorquing my head,which was rediculously loose??,and putting it back together I of course adjusted my valves.I fired it up and now it sounds worse than it ever did.What the hell did I do.I did this in the morning fresh with a couple of cups of coffee and clear headed.I am very methodical and careful.sounds like a bucket of bolts.or a very loose chain or valves.I dont get it.I am going to pull the valve cover this morn and check it.thank god I put in the frame kit.I am getting ready to scream(as well as my wife,she's pretty tired of my obsession)Suggestions Please?

[bikerbart]

so,I just checked the valves.One or two were slightly off but not too bad .so I readjusted them again,Could it be that when putting my camchain back on the sprocket I put it on just one link over to the left or right???would that do it?Screw up the timing,etc?I know I did not drop anything into the case.Its just so friggin noisy.When I started this project I had no idea I was opening a can of worms.Maybe I should just send off my head to one of you guys and have it completely redone.Anyone want to trade a set of 341's for headwork??

[MCRider]

While we can guess from the "341" reference that you have a CB750, you should state that at the onset, even put it in your subject line to attract CB750 people.

Have you adjusted your cam chain? If that adjuster is in the relaxed postion the cam chain will sound like a rattlecan.

Set the timing marks to the left of the spring pole for 1-3 cylinders. (That will put the engine at 15deg after top dead center, the optimum place to set the chain)  Loosen the lock nut, loosen the jam bolt on the tensioner, the spring loaded plunger should push forward into the chain. Tighten the jam bolt then the lock nut, start it and see how it sounds.

If its still loud the tensioner itself may be sticking. Save that for the next post. Do above, first.

[bikerbart]

thanks,I will do that,I thought I did but not the way you described.You are right I should have noted its a 73cb750

[bikerbart]

I am confused about what members are saying and what the manual says.To adjust my valves the manual says to the left of the T mark,but members say right on the T mark.I know to adjust the cam chain its to the left which is 15 degrees off TDC,am I correct?Which is right?

[MCRider]

I am confused about what members are saying and what the manual says.To adjust my valves the manual says to the left of the T mark,but members say right on the T mark.I know to adjust the cam chain its to the left which is 15 degrees off TDC,am I correct?Which is right?

Adjusting the valves: align the raised mark on the case with the "T" MARK on the advancer. I forget if the mark is to the left or right of the "T", but its adjacent to the "T".
Adjusting the chain: rotate the crank forward past the 1-3 timing marks and stop at the left side of the first spring post. DO not come at it by rotating the crank backwards.

[bikerbart]

I did that,Always going forward,never backward.Its smoother ,BUT,there is a serious ticking,sounds like just one valve,but what do I know.The ticking wasn't there before so I assume I did something wrong.I did it twice already,could I have harmed anything or is it just a matter of timing or readjustment??As I stated before I took the cam off to retorque my head and could putting the camchain back on one link to the left or right on the sprocket would totally screw up my timing?and/or causing the ticking sound???

[MCRider]

I did that,Always going forward,never backward.Its smoother ,BUT,there is a serious ticking,sounds like just one valve,but what do I know.The ticking wasn't there before so I assume I did something wrong.I did it twice already,could I have harmed anything or is it just a matter of timing or readjustment??As I stated before I took the cam off to retorque my head and could putting the camchain back on one link to the left or right on the sprocket would totally screw up my timing?and/or causing the ticking sound???

Wow now we're just fishing around. The fact that it didn't do it before limits some options. To answer your question, I can't see that slipping a tooth on the sprocket would automatically cause a tick. It would likely run poorly, have you riddn it?

Pretend that it did it before. Does the cam chain tensioner work? Loosen the lock down bolt. Put a prod, like a small allen wrench in the hole at the end of the tensioner and apply light pressure. Turn the engine over at the crank, you should feel your prod move in and out 1/4 to 3/8 inch, as the chain gets tight and slack. If your prod isn't moving, then the push bar isn't moving (they sometimes seize) and just loosening the bolt and expecting the spring to push it is expecting too much.

Did you remove the head and the valves, cylinder and the cam chain roller.

[andy750]

Nothing to do with your valves but did you change your exhaust recently? And if so did the ticking sound appear after that? If yes check for air leaks around the header bolt...sounds very similar to loose tappets.

good luck
Andy

[bikerbart]

Yes ,I rode it to work today.Fired right up,very smooth but the ticking.I did not remove my head but I did pull off the cam,towers etc. to retorque my head.Mind you this is after about 700 miles since I did a rebore,new rings,HD studs,gaskets(greasy rat 73cb750 build)I did not remove my exhaust but I know what that sounds like and it is similar.I have the carpy exhaust and it was'nt the easiest to fit so I will check to see if there is a leak.Curious.

[MCRider]

How did you do that work without removing the exhaust? nevertheless, agree with Andy, leaky ex can make a tick.

[bikerbart]

I did all that work previously.You misunderstood,I did not have to remove the exhaust to retorque my head.I didnt remove the head or cylinders,I just removed the valve cover,camshaft,rockers,but the head stayed on.All I was doing was retorquing the cylinder studs,so while I was at it I readjusted my valves since it was open.

[MCRider]

I did all that work previously.You misunderstood,I did not have to remove the exhaust to retorque my head.I didnt remove the head or cylinders,I just removed the valve cover,camshaft,rockers,but the head stayed on.All I was doing was retorquing the cylinder studs,so while I was at it I readjusted my valves since it was open.

Sure, I get it now. Well carry on.

[bikerbart]

so,I stopped by a very good mechanic in town and His opinion is the ticking is a loose valve seat.ALSO,my bike is smoking now at take off and downshifting.So I probably have a broken ring.That really sucks because I rehoned the cylinders and put new rings ,I just dont get it.I cant win.Now I dont know what to do.I spent 7 months in my spare time working on my bike and now this.I have to pull the head,send it to someone who knows what they are doing,pull my cylinders and find the source of the smoking problem.I am tempted to throw in the towel.I have owned the bike for 8 years now and its been no problem whatsoever until I had to go and mess with it.So it leaked a lil oil ,but it ran good and didnt smoke.While I had the head off over the winter is when I should have sent it off.But there was no problem other than a little oil.I shouldnt have fixed what wasnt broke.Now I got a sweet carpy exhaust,dyna s and everything else I put into it and now this,I'm tired.No riding season for me I guess,which just about breaks my heart.I have had bikes for a long time now and cant be without one.I'm sure there is a few of you out there that understand.

[Skonnie Boy]

I just rebuilt the top end on my 750 and was left with a similar sound.  Three of my eight tappet covers are stripped and stuck, but when I get them off and adjust the lash, I'm sure it will be fine.  Either that, or its the carbs gunked up and out of tune after two months of sitting semi-empty.  Sometimes a bad carb synch can make your engine sound like a lawnmower on the first day of spring.  The ticking could be one cylinder et. al. being affected by another one poorly running.  Maybe.

[CBGhia]

Did you use the rubber bands when putting the rockers back on?  You could have bent a valve and it would make a bunch of noise and probably cause a leak if it messed up the guide.   

[andy750]

Hey Bart sorry to hear that and yes it does suck when it happens in July. Been there and done that. I spent a whole summer rebuilding my K2 stuck in a garage when it was really hot and kept at it. By October I had a running bike and it was all worth it. Just depends on how much effort you want to keep putting into it. As you said we have all been there thinking about throwing in the towel....

This is why you need a second bike!

good luck!
Andy

[MCRider]

Did you use the rubber bands when putting the rockers back on?  You could have bent a valve and it would make a bunch of noise and probably cause a leak if it messed up the guide.   

The 750 doesn't do it that way. The rockers are installed in stands on top of the head, independent of the cover. Pretty hard to mess up.

[bikerbart]

I am going to pull the head.Seems its getting easier everytime.Hopefully its obvious and I wont have to pull my cylinders.As I stated before,I am glad I put in the frame kit.What is wierd though is riding to work on the highway yesterday there was power in the 65-70 mph range,same rpm's as normal.ALSO,after 15 min on the freeway,no ticking sound.My mechanic says a loose valve seat can reseat itself then come loose again intermittently,believe me,the ticking sound was quite obvious(and it wasnt an exhaust leak)Headwork will run me what,$300-400+++++.God I wish I had 3500 bucks layin around so I can buy a cycle X hot rod motor.

[MCRider]

BB: never heard of a valve seat coming loose on a CB750. In case you don't know. The seat is a ring of hi quality steel which is pressed into the aluminum head. Then the steel valve closes against it making the seal. I have heard of seats coming loose on other engines but its rare. Could be. If the seat is loose on a CB750, I can't see any way to repair it, the head is toast. Don't get excited, a good head shop can likely do something with it. WTFDIK?

Also, on an older CB, don't remember your age, the rocker shafts could float and tick, no harm at all. The newer ones used a bolt down method to stop the floating.

Could be a guide is loose, I've heard of that. Did you replace the stem seals previously? If not they can cause smoking. Cheap fix.

You can spruce up the head yourself for the cost of gaskets. Disassembly and inspect for the tick. Have the chambers and the valves cleaned, or do with a wire brush on a drill. (Talk to us before proceeding with that.)

Lap the valves in for a fresh seal, can be done with a drill and 6" rubber hose/fuel line.

I'll bet you find it.

[traveler]

Valves adjusted....cam chain adjusted.....all fine....perhaps low oil pressure?  Are you running synthetic oil?  If so, it may be too slippery, or oil in general may not be thick snough.

~Joe

[bikerbart]

same oil I have always used.Last time I used a fancy oil I got clutch slippage.Castrol 10w-40 has always worked fine in my bike.What would cause the blow by and burning oil other than rings?I took the day off today and I may just go and pull the head.Or should I just ride it and wait for something to happen???

[MCRider]

same oil I have always used.Last time I used a fancy oil I got clutch slippage.Castrol 10w-40 has always worked fine in my bike.What would cause the blow by and burning oil other than rings?I took the day off today and I may just go and pull the head.Or should I just ride it and wait for something to happen???

Did you replace the valve stem seals? Smoking out the exhaust pipe comes from 2 place primarily: leaky valve stem/guide seals and rings.

I'd say if its acting OK, throttles up and down smoothly etc,  I'd put some SeaFoam in it, gas and oil,  and ride it. Watch your oil consumption.

But its not my bike...

More thinking out loud... you say it didn't tick, you worked on it, now it ticks. So something had to change. you say you honed the cylinders and reringed it. Used the old pistons over? Did you check your piston to cylinder clearance.  They are worn to begin with, so honing makes them a little looser. Could have some piston slap in one cylinder. If so, ride it till you put the 836 kit in.   

[traveler]

many times, blow by occurs from valve stem SEALS getting old and letting oil slip by.  Depending on the mileage, the valve guides can also wear to the point of allowing oil into the chamber.  Compression tests done both "dry" and "wet", i.e. squirt a tad bit of oil in through the spark plug hole will give an indication of what is worn.  If compression goes UP when wet, then it's the rings.  If not, then it's in the head, mostly likely valve seals.

Best bet is the seals though.  Unless you have like 50K on the motor, and the oil has been changed regularly, it is the seals.  These motors are just too well engineered to have major problems early on.

~Joe

[bikerbart]

Thanks everyone for the responses.I am pulling my head this morn,probably going to send it out to get freshened up.I want this to be leak and smoke free.I want it to be right,I wont be satisfied after all this work for it to be leaky and smoky.

[crazypj]

It probably you set valves on wrong stroke
 There are two TDC positions for each cylinder, one on TDCC (compression) one on TDC overlap.
 Re-check clearances first.
 Watch intake valve, as its coming up, your getting close to compression

PJ

[bikerbart]

I did that,I was sure of setting the right valves.

[crazypj]

You didn't use metric spec with inch feelers?
 You did curve/bend feelers to fit under adjuster?
 Did you check intakes with 0.003" 'no go' after setting to 0.002"? (and exhausts with a 0.004" 'no go')
 I'm just throwing stuff out before you tear into it

PJ

[bikerbart]

Thanks but I already tore into it.gonna a valve job.

[MCRider]

Thanks but I already tore into it.gonna a valve job.

U go bro! let us know what you find, I'm curious.

[bikerbart]

Yeah,I cant do a band aid fix.I gotta do it right.I have new valves seals.Wodering if I should pull the jugs as well?I got great compression.(had)I just wouldnt feel right riding on the freeway and always having that feeling that something is wrong.

[bikerbart]

So,after tearing the head off I discovered an exhaust leak on cylinder 2.As I stated the carpy exhaust wasnt exactly easy to fit.Would not seal no matter what.But that doesnt explain the smoke.It explains the ticking.So I have new valve seals so I am going to put those in.Should I or should I not pull my cylinders??I took pics and will post on monday(work)Anyone out there with a carpy exhaust have trouble getting it to seal?I am beginning to chill out on the whole matter,nothing that cant be fixed(as long as you throw enough money at it)AND I am learning.So is it rings or valve seals for the smoke???

[bikerbart]

my exhaust valves were hitting my pistons.Timing issue it seems.but it still doesnt explain the smoke.still wondering if I should pull my cylinders.

[MCRider]

my exhaust valves were hitting my pistons.Timing issue it seems.but it still doesnt explain the smoke.still wondering if I should pull my cylinders.

Dang! That would make a tick.

[bikerbart]

I am almost sure that I put the camchain on one tooth over to left/or right.Also the exhaust leak wasnt just soot or carbon it was greasy wet???

[crazypj]

Better pull cylinders and check if top land has trapped ring. (highly unlikely but would suck if it has)
Also check valves didn't tweak and crack valve guides.
 How did you manage to get cam timing out?
 Forgot to pull chain tight on front run?

PJ

[bikerbart]

I found my sprocket was over a tooth.ex valves hitting pistons. .No damage though. :-Xredid it,adjusted valves(again),new gaskets,set timing,bigger jets in carb,Runs like a swiss watch...(I mean,a HONDA)Actually is running great again.Rode to work this morn,70mph freeway cruising ,the bigger jets with the carpy pipe really is a noticable difference,I went from 105 to 110 to 130 (only ones I had layin around,figured what the heck)Finally when I get on it between 70-85 mph there is power,what fun.

[bikerbart]

Oh yeah,freshly oiled K&N filter in a fresh rubber airbox helps too.