Bent Valves or No?

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Pips = the dimples in the back of the #4 right-most cams that I posted a picture of previously. Those holes can be used to confirm the proper cam timing, but I would also attempt to use a mirror and view the marks on the right end sprockets.
Two alignment checks are better than one.
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Okay, NOW I understand why you were so grouchy earlier about the importance of the #4 end! It is great to have you here but I do not always understand your logic or your irritability. I guess if you had tried to explain it then it would have made no sense. Thanks for the info and for being so subtle with your "I told you so". Good Stuff, my friend.

Pants, the more time you throw at this to try to fix it yourself, the more money you will have to pour on it later.
The questions you are asking, and the follow up questions that you are asking, indicate that it is not really fair to the owner of this bike that you continue to work on it.

Find a dealer with a good mechanic and trailer it to them.

The bad news is that this is their busy season, and the bike may have to wait for some time.

The other thing you could do that might be fair to your friend is accidentally back over it in your driveway ... of course I'm kidding (wink, wink, wink), but you get the picture.

You're two torque wrenches away from owing your friend a bike, and you can't dig out of a whole with torque wrenches.
I 1000% disagree. The questions he is asking, the information he has received, and in fact this entire thread has boosted my confidence tremendously. With the best minds of this forum backing him, 'Pants can fix anything. At this stage, I am prepared to bring both my '15 and Dad's '07 over there for him to do the valve check/adjustment to them.

I won't of course, because I would rather take up his time with riding on bikes instead of working on bikes, but that is not the point.

Another factor to consider is that MikeP (the bike owner) went into this with both eyes open. He and Joey have been riding together and working on their bikes together for some time. IF the bike were toast, which it is not, he would be shouldering at least half of the responsibility. Mike is a smart guy, he has confidence in his friend. I do too.

 
I agree RFH. I was in a similar situation with someone else's bike. Had already done 2 valve clearance checks, but didn't have to adjust anything. I think they are approaching it the same way I did. Ask a lot of questions here and not rush the job. I got frustrated a few times, so I just walked away. They will earn some valuable experience. It really isn't that difficult either. It is the unknowns and needing piece of mind that you get it back together properly. The FSM is good, but reassurance and assistance from the forum collective is invaluable! Rock on Joey and Mike!

 
The torque spec for the cam bearing caps is 10 Nm/7.4 ft/lb.Compression normal approximately 198-228 psi as Yamaha FSM say.

 
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The torque spec for the cam bearing caps is 10 Nm/2.25 lb.Compression normal 15-16 bar/198-228 psi as Yamaha FSM say.
10 Nm = 7.4 ft/lb & the bar to psi is correct. You won't measure the full 230 psi, typically it will be in the 200 - 210 psi range.

 
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The torque spec for the cam bearing caps is 10 Nm/2.25 lb.Compression normal 15-16 bar/198-228 psi as Yamaha FSM say.
10 Nm = 7.4 ft/lb & the bar to psi is correct. You won't measure the full 230 psi, typically it will be in the 200 - 210 psi range.
You are right!My fault when i did the conversion..

 
Well - we pulled it apart and the motor spun freely without the cams in it.

Next, we were able to put the cams in time with the crank following the instructions in this thread. Assembled, we spun the motor by hand 8 revolutions and every two, all marks came right back to right.

Next, we checked the valve lash and it was adjusted with the new shims as we expected all around. I feel this important because even if a valve is bent slightly, a different reading of some sort should be expected on that valve lash measurement. Does anybody agree with this?

So far, so good.

Uh... maybe not.

Next up, we bought a compression tester from O-reiley Auto Parts and here's what we got:

#1 - 180

#2 - 175

#3 - 180

#4 - 100-105

All seem low based on info in this thread, but that could be the gage and other factors (cold engine). What worries me is the difference in the #4 hole. Based on the previous info on this thread, I know that the intake camshaft was out of time, and the #4 intake lobes were straight down. I'm hoping that I pushed the piston with the valve, but who knows?

Two things may have affected the c-test.

1. We did it with the motor stone cold. FSM says to do this test with the motor hot. I suppose metals to expand and perhaps seal up better at running temperature.

2. The battery didn't seem to have full punch. We put the battery on the tender overnight and will check it again this morning.

Also - each cylinder holds pressure on the gauge, but I think the gage may have a check valve in it, so that doesn't mean the pressure is holding in the hole - yes?

I don't know how to do a leak down test. I'm going to try to research that this morning.

Edit - I learned about this on Youtube. I'm going to see if we can rent a tester at the parts house. I have compressed air. The Chilton's manual doesn't give a leak down speck (what % of air leaking is acceptable). Also, what air pressure does Yamaha say we have to pump in the cylinder before the leakage is measured? Can anyone attest to this spec per the Yamaha FSM?

We couldn't get the valve cover gskt to stay put up re-assembly, so we cleaned and dried it up and put a little RTV in the cover, set the gskt in place, and allowed it to dry over night.

We will see what happens this morning. I'm inclined to believe, again - that I can't hurt it anymore than I already have - if I have at all. I think we are going to put it back together and see what happens.

 
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I don't have a warm and fuzzy feeling about #4.

Good luck with it. Hopefully the low reading has another cause. In any case, you don't really have much to lose by firing it up since you know the timing is correct. Once it has been run (if it will run) you can do the compression and leakdown tests again. If the valve is bad, I'm wondering if an Ebay engine replacement is a cheaper bet than the head work.

 
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Since it is still open, are you absolutely certain that the clearances on #4 are exactly what you expected? If they are, I really do not see how a valve could be bent and not seating properly.

You can repeat the compression test after squirting some oil in cyl 4. If compression is then good it would indicate the rings were the leak, which would have absolutely nothing to do with the valve issue.

I would finish putting it back together and see how it runs.

 
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The cold compression readings are typical.

Put a little oil in cylinder #4, spin the engine a bit and try the test again. If the readings go up the issue is the rings on the piston sticking. This is common for the FJR and a little Yamaha Ring Free will sort it out. Ring Free is highly concentrated so read the container and dose accordingly.

If a valve were bent you would have almost no compression. I'm pretty sure it'll be sticking rings (or a gauge that wasn't fully threaded in and sealed).

Edit: I see Fred posted the correct troubleshooting process while I was typing in the Spark thread.

 
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The #4 difference is meaningless without a baseline of what it was before. As has been stated, rings can cause low compression just as much as valves. Also, if there's a valve problem that was already there, such as a burned valve or a carbon deposit, you again might be reading what you'd have read prior to the work. A leakdown would tell you more about that.

Since it goes around cleanly by hand, you're not sticking a valve into a piston. It's ready to run, then you can repeat the compression check when warm.

 
A leak down test with the engine on the COMPRESSION stroke @ TDC for the cylinder being tested will tell all. (engine locked down so it WON'T SPIN OVER)

It'll give you a good idea of the health of the internals.

You'll either hear air come out of the TB's (intake valve(s), exhaust (exhaust valve(s), or crankcase-(piston rings)

Per OTC, a difference of 5 PSI between the cylinders is satisfactory. 10-15 PSI, you need to start digging..

This is what I use and seems to be very accurate... : https://www.otctools.com/products/cylinder-leakage-tester-kit

With 100 PSI on compression on #4, I suspect a valve is bent there...

 
The leak down test will just confirm if the head needs to come off for certain.

Weather the valve got just slightly bent, not enough to seat FULLY or something else, 100 PSI is NOT good..

 
A little late for this job. But a couple tricks others might keep in mind for when they do this. Some of this may be obvious and you may have already done it. In no particular order:

1) Pull the spark plugs. Makes turning the cylinders way easier.

2) Put a long screwdriver into the #1 cylinder spark plug hole. Makes it very to visually see when you are approaching TDC on that cylinder.

3) Take a ton of pictures before every single step. Digital film is cheap and the ability to go back and see what something was earlier is incredibly handy. Take pics from every conceivable angle, close ups, overall shots, everything. It can all help if you make an oops!

4) The markings on the cam sprockets are indeed a pain to align since the frame is in the way. I think they were designed assuming you had the engine out of the frame and on a workbench. So scribe a copy of the alignment mark that you are matching to on the backside of the sprocket. Makes it much easier to see alignment during reassembly.

5) Use zip ties with different colors to indicate both which is intake and which is exhaust, You can also put the zipties through the holes in the sprockets so that they (roughly) line up with the cylinder head. Makes it very easy to immediately see if cams are aligned properly.

Hope this helps

- Colin

 
Just letting you guys know you can stop stressing over the low reading on #4. The advice given by ionbeam and Fred W about squirting oil into that cylinder brought the pressure up. I am quite certain hppants will be along shortly to share the results of his work. I would tell, but it is not my story...
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Good news for the owner. The low reading may have just been a dry cylinder after the engine sitting for a while. He can redo the test after running it and getting the engine warm and the oil redistributed, or just forget about it and ride it. Unless it doesn't run right I sure the hell wouldn't be ripping the engine apart any further.

 
I love a story with a happy ending and this one will not disappoint.

I searched high and wide for a leakdown tester, but could not find one in town to ether, buy, beg, borrow, or steal. So we put that issue aside and checked in on this thread. Happy to hear from Ionbeam, Fred, and others, we decided to squirt about 10ml of oil into the #4 hole. I rotated the crank by hand about 5 revolutions to try and circulate the oil. Compression test on this hole bumped up to just under 150 psi. Very encouraged, we decided to press on.

We buttoned up the motor, double (TRIPLE) checked everything, and .....



Once the engine was up to full running temperature, the large hose behind the coolant pipe was seeping a little, so we broke for lunch.

In the afternoon, we were able to sync the Throttle bodies (Cylinder 2, 3, and 4 were all off from #1) and seal everything up. We adjusted the throttle cables and even re-torqued the engine mounting bolts (both bolts for the frame sliders were not tight enough).

We did not perform another compression test to see if things are more normal after the motor is up to operating temp.

I followed Mike on a 40 mile test ride and everything is good to go.

Few things learned to wrap this up:

1. We used liquid paper to highlight the timing marks on the outside of the cam gears. That helped a ton and with a more directed light beam, we were able to use line of sight down the top plane of the cylinder head to confirm good timing.

2. We did transfer some penciled marks onto the inside of the cam gears and that helped to get us on the right tooth.

3. Intech's "leading a tooth" method was the shit and was very helpful in setting the cams on the right tooth.

4. If I was just checking valves or changing the CCT, I would not remove the timing rotor cover. However and otherwise, I absolutely would. There is a plug you can remove to simply turn the crank (you can also spin the wheel with the bike in gear), and there is an inspection bolt that you can remove and look at a mark that is supposed to show you #1 TDC. But for my money, I'll spend the $7 on a cover gskt and see the proper timing mark on the crank gear with my own eyes.

5. A small squirt of silicon spray on the cooling pipe barbs was very helpful in installing the pipe (especially on the big hose).

6. I think this has been mentioned elsewhere, but rotating that hose clamp for the big hose about 45 degrees clockwise makes it much easier to install and tighten.

7. I need to stop over thinking the valve lash. I have some "go or no go" feeler gages. Earlier this week, I called Friendly Yamaha to discuss the situation and see if they would be willing to put it back together if it came to that. This guy told me that DIY mechanics over think valve clearances way too much. The spec given from Yamaha is a go or no go spec. He said that if at 26,000 miles (for example), you check the exhaust and a 0.007" feeler gage can fit in (tight or otherwise), then it is in spec and you can leave it alone. Yamaha offers this spec such that even if the lash is at the tightest point of the interval, then it won't tighten enough over the next 26,000 miles to cause engine damage. At the next check, it will need a different shim. But at this check, it's a "go" and you can leave it alone. Forget about this "loose 7" or "tight 6" crap. It's either a go or a no go, plain and simple.

Finally, and MOST importantly, we couldn't have finished without you guys. Admittedly, we probably wouldn't have started in the first place without you guys anyway. But I'm humbled by your willingness to help. I hope to return the favor in my own way some day. I sincerely appreciate your advice, one and all.

Tomorrow, I think I will go for a ride....

 
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