Possible bent cam? Ways to check?

So trying to get my bike on the road again And some of the valves are out of spec( like .6 if memory serves) @TheCrazyGnat and I are trying to figure out this big gap and are wonder if there isn't a slight bend in the cam somehow? Is there any way we can check this before I resort to buying another cam? And other suggestions for addressing these gaps? Some of you might remember I had snapped a cam chain a couple years ago and had taken it to a shop to have repairs done, they said they the clearances all in specs but they either lied or something else happened considering out of intake and exhaust only one valve was in spec....

 

Is that 0.6 millimeters, or 0.6 inches?
Do you have a dial indicator?

 

Millimeters and no I don't believe we have one, I know I don't but not sure about crazygnat...

 

A couple of years of not checking your valve lash , depending the miles and how hard you ride, and the valves are surely going to be out of spec but usually tighter.
With huge clearances your bike wouldn't run at all. Double check your work and use metric feeler gauges.

 

if your cams are bent i would think that the cam caps would wear uneven.
if shims were tight that may force the camshaft to contact the cam cap and cause high wear on the cap.


https://www.harborfreight.com/clamping-dial-indicator-93051.html

 

The work to the valve was finished beginning of June of last year right before I went up to the CNYCC....that's when the shop said everything was in spec, only got to ride for about 3 month at best so I'm 99.9% sure it ain't from riding lol. And metric gauges were used

 

If the cam were bent enough to have that large of a gap you'd see the bend as the cam turns. Pull the spark plugs out and turn the engine over by hand slowly. Watch the cam as you turn the engine over.
I highly doubt that the cam is bemt.
I highly suspect that the shop was looking at the wrong spec sheet (if they bothered to look at one at all).

 

I have a video somewhere of the cams turning I'll give it another look but I don't remember seeing anything like that... Yeah I'm thinking they just threw things together, between that and them having 5 different people work on it and them taking the better part of a year to get it done.... The variance between gaps was pretty wacky too....

 

Here are the valve clearances, for what it's worth. And yes, we were using metric gauges. I did check I1 and I2 multiple times.

I1: .6 290
I2: .6 285
I3: .24. 290
I4: .17 280

E1: .04 270
E2: .09 270
E3: .16 265
E4: .15 265

Smeagol should have a video of me turning the cams ( with my commentary, ha ha). Currently the cams, chain, etc are all off.

I have no idea if it means anything, but the top cam chain guide is the one that was in the bike, the one below is a good oem one. I can't think of a reason for the guide to have been bent like that in the engine...

I don't have a dial indicator.

 

My thought at this time is to:
-check the cam chain tensioner
-replace the cam chain guides (We have used oem replacements)
-replace chain (the aftermarket one in there now has some bound up links)
- set timing
- check valve clearances again
- do a compression test
- go from there

If anyone has anything else to try/add, we are all ears.

 

so with these 2 measurements you need a new head

I1: .6 290
I2: .6 285

look and see if the shim buckets are damaged or valve stems beat short

measure cam lobes . intake should measure 36.5
could they have put cams back in wrong place?

exhaust 35.8mm

edited incorrect intake cam measurement

 

New head?! Dude...you're breaking my heart! (And my wallet!) Is that a surefire thing or could it be one of those other thinng?

 

there is no shim replacment listed for your measurments. I would look at valve stems, guides and buckets
maybe the 2 valve seats can be cut deeper to close the gap


I do not think it is possible to swap intake and exhaust cams and bike run due to specs I read.

with the shim clearance you showed the cams coud have worn down . the tips of the lobes would make contact very late putting the force on the ends of the lobes

did you measure the shims maybe they put them in upside down and wore them down or ground them down

 

I know at least one valve is new possible two, I'll call the shop and ask to see if they remember, maybe that's the whole problem! I don't remember if we checked to see if they were upside-down, honestly I wouldn't have thought it would matter so I learned something new!

 

only the top of shim is hardened

 

The intake:

1 - 1.437" 36.5 mm
2 - 1.437" 36.5 mm
3 - 1.433" 36.398 mm
4 - 1.429" 36.297 mm

I believe it is possible that one of the Shims was upside down, but no more than that. I had to measure intake number 1 because the stamp was completely worn off ( assuming that I couldn't see the label because it was installed upside down and the lobe wore it off). The rest of them had the marking on the bottom.

They were measured in inches, unfortunately, I don't have metric calipers.

 

are those numbers the shim thicknesses?

decimal point is in the wrong place maybe? or is the 1 actually an I but again 36.5 mm is almost an inch and a half thick.

 

Sorry, those are the intake camshaft lobe thicknesses (as l measured them).

 

seca650 cam spec so cams are good

 

it should be possible to have the out of spec intake valves cut deeper into seats or refaced to correct the problem of not being able to reshim

 

I have heard that it might be possible to put a shim in under the bucket. I've never had the need to do that, so I've never looked into it. Would that be a possibility?

 

No. Shim under bucket systems are different, and there is no provision for putting a shim under the existing bucket. Even if there were it would be a bandaid (a cheap, off-brand bandaid that would fall off after it got wet).

It is possible (but extrememly unlikely) that the valve seats were redone at some point, but not set deep enough. Another possibility is that some DA PO tried to adjust the clearances by grinding the valve stems (like on a a lanmower engine).

I think it's adviseable to pull the head for inspection, or just get a replacement head.

 

Lobe size is not the problem here. Lobe size it for lift it's the base size that determines clearance. So possibly the base circle of the cam is worn creating the big clearance.
A picture of the opposite side from the lobe may tell a story.

 

Shims are hardened both sides. That's not the issue here. Do NOT put shims under the buckets!!!!

I still am suspect of the valves themselves.... seems like they're too short.

Both crazygnat and I are still on this, too.

Post the video clip of the "snap", as well. (Didn't we narrow that down to sticky chain links though)

Dfox

 

Apparently the shop replaced at least one valve. They had to send the valve out to get the seat cut, then all of the valves were lapped and supposedly in spec, for what that is worth. I can't imagine everything was in spec and in three months of riding things went this horribly awry.

I'm sorry, I'm not quite following. Are you saying to measure the "width" of the lobe (if we were to call what I measured before the length)? Or the round post that rides in the bearing surface of the head(I'm not sure of the correct terminology here)?

@hogfiddles : We were satisfied that the chain "snap" was due to the bound up links, I think it would be helpful for Smeagol to post the video to show the cam rotating. I didn't notice anything wrong, but maybe the better trained eyes here can. Also, did you see the picture I posted earlier? The front cam chain guide was bent all out of whack. I don't know if that is a symptom or contributing factor to the chain issue.

 

@hogfiddles : We were satisfied that the chain "snap" was due to the bound up links, I think it would be helpful for Smeagol to post the video to show the cam rotating. I didn't notice anything wrong, but maybe the better trained eyes here can. Also, did you see the picture I posted earlier? The front cam chain guide was bent all out of whack. I don't know if that is a symptom or contributing factor to the chain issue.[/QUOTE]
Yeah, that's what meant.

I don't recall a pic of a bent chain guide.....

 

I attached the pic on the previous page of this thread.

 

Lobe height is lift( lobe pushing down on shim and bucket) base circle is diameter of cam with no lift. Hope that makes sense.

 

If a valve stem were bent, or had a burr, or if the valve guide was damaged or not of the correct size, that could cause the valve to hang up, and clearnace would be excessive.

 

I've got you now. Sorry,I can be a little slow on the uptake sometimes.

 

I would not be one bit surprised to find out the issue is with the valves; I have been less than impressed with the work I have seen so far.

 

With the shop that did the work it's actually extremely likely in my opinion that the shop didn't cut the seats deep enough... Are there measurements or something to check that?

 

I'm trying to figure out how to attach the file, I could send it to you in a text if need be but yes there were several sticky links in the chain...

 

To say the least! I shouldn't laugh but yeah not the best work....

 

There are specs in the service manuals. AFIK they are correct, as both the Haynes and Yamaha manuals agree on the dimensions.

 

Too deep / not deep enough? So which is it here? From the skim read I've had I think I understand excessive clearance, so the only likely possibility is seats cut too deep, valce refaced ecxessively, or they shortened them at the stem tip.edit to agree with valves sticking open possibility.
If you can't get a thick enough shim it's head off time, do some looking, some comparing, and some measuring.
Your head may be fine, if not, a replacement good one not too expensive. Not the end of the world.
Oh, and to be pedantic, the "width" or measurement across the narrow bit of a cam lobe cannot be guaranteed to be the base circle diameter, it depends where the opening and closing ramps are. And from this, the measurement across the wide bit is not the lift. Lift is the difference between half the base circle diameter and the width across the lobe, once you've accurately determined the base circle diameter.

 

For there to be excessive clearance the seats would have to have been cut too shallow.
Refacing the valve excessively would result in tighter clearance.

 

That's what I thought but I've never messed with an engine this much....yet! I'm going to look into getting a valve seat cutter.... I know the shop owner had the head sent out twice to be recut and the finishing "work" was rushed to completion.... So it would come as no surprise is they just got sick of dealing with it and slapped it all together enough to run it....

 

I can honestly say I'm not drunk, so why I wrote that drivel I don't know. Please ignore my post..
Shall I try again?
Excessive clearance - don't see it anything to to do with cutting seats, if the seats were fine before. So, the cle to this could be that the valve was sent away to be refaced - did the use oversize valves ground down? Are they available - 600valves perhaps?
A thousand appologies again.

 

do you need an XJ650RJ factory service manual?

all your specs are listed in the fsm for valves seats and cams

 

Couldn't tell ya man, other than they are aftermarket... Extent of my knowledge there, the shop took almost a year to "fix" my bike

 

uploaded a manual for you if you want it check your inbox

 

mark the links see if it is the same link , or is the sprocket tooth causing that action

 

that's normal. the valve springs, lifters and shims get to a point where they push the cam forward, the same direction that the chain was pulling it. it gets slack but it didn't jump a tooth or the cam would be out of time. it just happens to be as that bolt goes by.

the description you gave sounds like a rod bearing to me

 

I did not know that XJ 550H but I made sure the numbers on the shim were facing the buckets when I changed my shims.

 

Sorry guys, that video was about three weeks ago when we were working on it, the cams and chain have since been removed. We were planning on putting on a new chain, checking the tensioner, putting in New guides, then putting everything back in making sure to torque everything down correctly. The hope was that we would measure the valve shim clearances and all would be reasonably close to in spec.

I thought maybe the video showed the cam more straight on than it did, I guess I was mistaken. We did peek down in there and turned the crank after wremoving the cams to see if any of the teeth on the crank and nothing appeared bent out broken.

@Polock : what leads you to believe it might be a bearing?

 

i don't know, i think my threads got wound into a rope. disregard that