Examining Real Valves
 

hi.

i've removed carbs to get good access to rear cylinder head in order to examine valves. i believe that my cam chain slipped last weekend when i was inching forward to make a left turn at an intersection. normal sounding motor all of a sudden began clanking alarmingly. parked and shut down motor after clearing the intersection. started it just long enough to ascertain that the clanking was coming from read cylinder. had the bike towed to my garage.

this is new territory for me. i've never opened the top of the motor.
i'm reviewing Calitoz CCT how-to thread. in order to pull the cover and examine the valves should i have the bike at TDC for the rear cylinder? as i'm turning the motor, i'm getting clanks and am worried that i may be doing more damage turning the crank in order to find TDC.

thanks,

--fred

I'm not sure what the clanking means (sounds bad), but you don't need to be at TDC to pull the cover off. The valve cover just exposes the cams and cam chain- you actually can't get to the valves from there, but can inspect the timing and such...

4 bolts and you're in!

Be sure you have access to a shop manual for the. Ike and just start with the section on checking valve clearance. It should be fairly obvious if you have bent valves.

thanks guys.
and, yeah, i have the shop manual.
i hope i'll see what is making the noise when i take the valve cover off (bent or broken valve maybe?). if i see obvious damage due to slipped cam chain, i'll then need to try and determine if the piston is damaged. if the piston 'kissed' a valve and the top of the piston got 'notched', what does this mean in terms of piston performance and how would i go about verifying the extent of piston damage, if any?

and, true to form, i have a typo in the thread title... i meant to write, "examining Rear valves" .

--fred

I think the only way to determine piston damage is to remove the head. This is the casing that the valve cover is bolted to. If you do this, you need a new head gasket and have to have all the proper torquing tools to bolt it back together (really just a torque wrench, but it's pretty important to get the bolts back together correctly on this one). I'd make sure that your valves aren't seating properly by doing a valve lash check like cliby said before digging into that part.

ok, i'll definitely test valve seating with valve lash test before i do anything further in order to avoid overzealously pulling things apart.

thanks for the advise.

--fred

i cut the a stopper tool for the cam chain tensioner according to the template on page 8-4 in the service manual. just removing the valve cover doesn't show me anything that looks out of wack. i figured, heh, why not rotate the motor until i get to the 'RT' mark to take tension off the rear cam chain. no can do. i can rotate it to 'FT' but when trying to go around to 'RT' in 6th gear with both spark plugs out, the motor gets to a point where it refuses to turn any further no matter how much pressure i put on the rear wheel. i'm sweating from the effort. i take this as a bad sign. anyway. i'm getting ready to remove the camshaft so i can get a look. and am following instructions for this in 'camshaft removal'. i have my cam chain lifter stopper tool, although it isn't exactly true. but it's close. here goes.

now i'm not sure whether to move forward or backtrack. and where else to look.

as i said above, the rear wheel would seized before i could turn the motor to the RT mark. i figured i would find something bad underneath the valve cover. nothing looked obviously broken when i removed the valve cover. i turned the OEM CCT in fully, secured it with a stopper tool and removed the sprockets, holders, valve lifters and shims. i did notice that i could turn the motor to RT by rotating the crank bolt with a wrench? but cannot turn it past a certain point if moving the drive chain my rotating the rear wheel.

could it be that something broke or is jammed in the drive chain instead of any rear valve problems.

here's what it looks like:

https://lh4.googleusercontent.com/_z...rstoppered.jpg

https://lh4.googleusercontent.com/_z...pper_tooil.jpg

https://lh4.googleusercontent.com/_z..._shims_off.jpg

https://lh6.googleusercontent.com/_z...oved_parts.jpg

any suggestions?

thanks,

--fred

Is it hard to turn with the plugs out? Certain parts of the rotation are harder to do using the rear wheel method. Are you noticing any metal-to-metal binding when you turn the crank with a wrench?

You're actually not looking where the valves seat with it taken apart like that. You're looking at the top of them- just the lifters and springs and such. In other words, if anything is seriously broken, you won't see it from here. The bottom of the head (you can see the split in the middle) looks like this:
Attachment 26106

When those pieces are out of sync (such as when your cam chain jumps sprockets), they are moving downward when the cylinder is moving upward and the two kiss each other and damage ensues. You can determine if this has happened by checking the valve lash, though (which the covers, shims, buckets, and cams need to be back on for). Again, avoid taking the head off right now or else you will need a new $30 gasket.

EDIT: Were you able to check the lash before you took the cams off? Or could you not even turn the crank with a ratchet/wrench when they were on? If you're turning the crank without the sprockets/cams, you're not moving the valves and can't really determine if there's a clearence problem.

If it were me, I'd set it to TCD (the RT mark), re-assemble the cams/sprockets according to the procedure in the manual (making sure the timing is correct) and check the valve lash as my next step.

it's easy to turn with a wrench on the crank-shaft bolt, with the plugs out and turning the rear wheel, it is easy to get to FT, either by heading for it clockwise or counter-clockwise, only one will work depend upon where the rear wheel has the crank turned to. i cannot get to RT by turning the rear wheel (even with plugs out), the wheel hits a spot where i can simply not turn it any futher. i have it in 6th gear, too, btw.

ok. i'd prefer not taking them off if i don't absolutely have to. i'd much rather be riding this bike right now instead of working on it.

i, unfortunately, did not try turning the crank with a wrench until after i'd concluded that i should dig further, because i couldn't check the valve clearance correctly since i couldn't turn the motor to get it to RT.[/QUOTE]

ok, i will slap things back together ...actually, i will Very Slowly put things back together, since i often drop things when i'm rushing. and i'd hate to drop one of those shims or sprocket bolts down into the motor where i will Never, Ever be able to retrieve it.
i will make sure the timing is correct (i expect that the shop manual will explain exactly how that is achieved) and then i will check the valve lash with feeler gauge (i think i have one long enough to get in-between cam and lifters. if not, i'll borrow one that is).

if the valve lash is way off on one or more valves, that would indicate that i need to continue and take the head off in order to remove and examine the valves, right?
and if, on the other hand, the valve lash is within spec for all 4 valves, then i'll be scratching my had as to why when i last ran the motor, it sounded like a penny was clanking around in the rear cyl head.

thanks!!!

--fred

Well the quick and easy way to check things right now would be to reinstall the shims, buckets and cams. Don't worry about the cam chains or crank position at this time.

When you install the cams have the gear installed and line the cams up as they would be in the TDC checking position (either up and in or up and out depending on the cyl.) and tighten things down.

Now just line up the cam timing mark with the head, hold it there and check the valve clearance.

If you have a bent valve it will be oblivious as the clearance will extremely large.

quick. easy. two of my favorite words.
TDC orientation for the rear cylinder. i didn't bring my shop manual to work with me :-) if i can't determine it from there or some thread searches i'll ask you to describe that to me, if you would.

the rest looks really straightforward.

thanks, i'll try it tonight.

--fred

Well I believe the rear cams are up and in and the front are up and out but it could be the other way, my manual is out in the shop.....;)

Just look at the cam gear. there should be a RI & RE marking with a line.
Aline the appropriate mark with the parting line of the valve cover. Hold it in place with your thumb and measure the valve clearance.

thanks! heh. i just saw that in the valve section. it is gonna be a hot summer. i better put vents in the garage roof.

last night was a bit of a wash as i pulled out my last Padron 1964 AS Exclusivo. i don't know what i was thinking. that's not a working cigar. got into the garage at about 8:30PM and didn't start re-installing parts until about 11PM, just in time for the whole block to go black because of a short above the transformer that feeds us. since i have established a decent collection of flashlights, i decided to "work-by-battery" . had plenty of light to reinstall shims, valve lifters shafts and holders. that's where i stopped.

tonight i put on the sprockets in orientation shown on page 8-21 of the shop manual.
i thought i had all the necessary tools, but putting a torque-wrench on the rear sprocket bolts with motor in the frame, even with a u-joint was not possible. red locktite and feel with a handheld wrench makes me pretty comfortable with those, though. then i installed the front sprocket.

i've got issues. my smallest feeler gauge is 0.013mm and that would only fit grudgingly into the front exhaust valve gap. "R-E" mark was aligned with rear of case and "R-I" mark was aligned with front if case. the other 3 gaps were too narrow even to fit 0.013mm feeler gauge.

i was expecting something different. either nice clean fit of 0.016mm into intake gap and big gap ~0.31mm at exhaust valve lifter/cam-lobe gap. or Big gaps indicating bent valves.

either i did somethings ass-backwards (not uncommon) or i've got valves pushed up too far. btw, i did align the crank RT mark, but i don't think that is relevant without the chain on.

could it be that the valves got jammed upwards?

man. i have a dentists appointment at 9AM. cold rain all day tomorrow. better put liner back in my jacket and hit the sack.

--fred

i'm going to re-install the chain and try reading the gaps again. the manual indicates that in order to get the timing correct on the rear, it is necessary to remove the front cover, and turn the crank bolt to align FT with the mark and depending upon how the front sprocket marks align, either turn the crank bolt ccw 3/4 (270deg) around or ccw 1.75 turn (630deg). i'm going to do this now and reinstall the rear chain and re-measure cam/valve-lifter gap (valve lash).

You actually don't need to do that... what you can do is pull the spark plug and put a long skinny stick/rod in the hole. When the rod rises all the way and pauses before dropping, you know that you're at TDC.

The rod is resting on the piston in this method, and just tells you when it's at the top of the rotation... I like to use a piece of plastic so I don't have to worry about scratching anything in there.

Edit: Do this to the cylinder that you're working on, not the front one ;)

cool! i am reading this right now after having removed the front valve cover :-). no big deal. it was an educational experience to correctly get access to all of the bolts and then remove the cover (its tucked in there nice and tight. i had to remove the left bolt on the seat to which the front plug cable holder is attached in order to rotate it out of the way enough so the crank breather hose connection would clear it) while doing one's best not to damage the gasket on the sprockets. i brought it down and off. it doesn't appear that there is enough clearance to pull it up and out.

next time i will use a PVC strip in plug hole to find TDC as you described.
thanks.

--fred

Yeah, I took the valve cover off a couple of times before a forum member taught me that trick ;)

using the shop manual approach ended up being problematic because as i was approaching 270deg counter clockwise, things would get pretty tight and then pop. hard to make sure that i was still on the right rotation to rear TDC. so i grabbed the plastic coat hanger tool i'd made to measure fork oil level or whatever when rebuilding my front end and dropped it into the rear plug hole. it's plenty long and i retained part of the angle of the hanger, so it can't fall in. i've got it at TDC and am reading and re-reading the shop manual in order to make sure that the cam shafts are in the correct orientation before i line up the cam sprockets with chain installed and torque everything down. i'm *pretty certain* that the cams are correct and neither is 180deg out of phase.

the front rear camshaft lobs are oriented about 15 to 20 degrees up from pointing directly back. the rear rear camshaft lobs are oriented pointing directly back.

--fred

As long as the cam lobes are pointing up (away from the lifters), you can check valve lash.

When adjusting valves on a car, which I've done probably 1,000 times, I never line up any marks if I can see the lobes. I just use a remote starter to tap it over until the lobe on the valve I'm checking/adjusting is pointing 180 degrees away from the lifter.

So, the method of checking the piston through the plug hole would work fine. Just make sure the lobes are pointing away from the lifters. 90 degrees is no good, you're still on the ramp.

jeez. i finally got smart and covered the front cyl image. i kept accidentally looking at it's sprocket bolt orientation at TDC, instead of looking at the rear cyl sprocket bolt orientation at TDC.

with the rear cam sprocket bolts oriented as shown in the shop manual at TDC and RE mark on rear rear sprocket aligned back and RI mark on front rear sprocket aligned forward the cam lobes are.... rear about 30 degrees forward from straight up orientation and front about 30degrees back from being oriented straight up.

i believe this is correct.

--fred

what's the trick to getting the front sprocket with cam chain onto the the cam axle? installed the rear sprocket, oriented it correctly TDC and laid the chain tight up and around it. but i've been trying to get the front sprocket in its correct TDC orientation with the chain on the sprocket teeth onto the front cam axle for about half an hour and i can quite get it forward to the point where the sprocket will seat on the cam axle. i have the CCT turned in all the way and locked. is that preventing me from installing the front sprocket?

thanks,

--fred

[edit]post script: ok i took my nitrile gloves off and went at the chain and sprocket toe to toe. my favorite Kline 7" #2 phillips into the sprocket hole that aligns with the cam hole and some serious grunting culminated with final rubber mallet tapping and i have the front sprocket on (not yet bolted) with rear RE and front RI marks parallel to the cyl head case.

Approximately 30 degrees off straight up (from the lifters) sounds good, with sprocket timing marks lined up. Did you use zip-ties to hold the sprockets to the chain?

Congrats on getting the front sprocket back on. I find that walking away and taking a break sometimes makes things go back together easier.

I need to check my valves soon, so I'll get to join in on the fun.:(

bad news. i can see with a flashlight that the rear cyl cam chain has slipped off of the lower sprocket and is on the lower sprocket shaft. i think that my CCT lock plug was supposed to prevent this from happening, but with all the grunting and misplaced torque generated, my little CCT lock plug was twisted into a helix and failed.

do i need to tear down into the cyl head in order to reset the cam chain onto the lower sprocket?

Having never done this job, my best guess would be to remove one of the cam sprockets to get some slack, then try to get down there with a long narrow blade screwdriver and guide the chain back onto the crank sprocket. But I don't know how much room you have.

Maybe someone who's had this problem will jump in.

Um, you're going to have a lot more ability to move the chain around if you back your CCT off- the sprockets aren't going to skip gears unless the motor is moving pretty fast, and it should be one of the last things that you set (it would probably have been much easier to get it over the sprockets too without the grunting)- bummer I didn't see your other post sooner.

I wouldn't go into it from the head- I think that you can see it from the bottom with your clutch cover off, (yeah the one on the right side of the bike with like 100 bolts). But easier than the head for sure. With either one you're going to have coolant spillage and you'll need gaskets for both too (the clutch cover one is much cheaper/less necessary though). Maybe you can work it on with one of those flexible magnet extensions?

One of these has paid for itself 10 times over for me...
Amazon.com: KD Tools (KD 1711) 18" Flexible Head Magnet Pickup Tool: Home Improvement

I can't remember if you can see it from the clutch cover or not...

thanks you guys. i actually have a pretty good view of it from above. i think that if i take the sprockets off and rig a coat hanger, i might be able to snag the chain and loop it off the shaft back onto the sprocket. i'll give it a try tomorrow night.

i dumped the coolant before i started this. although, i've not opened the drain-hole on the front cylinder... yet. if snagging it from up-top proves to be impossible, i'll investigate the clutch cover. although, i don't think it gives you access to that sprocket. i pulled the clutch a couple months ago and do not remember seeing that gear sprocket.

--frred