Boogered the valve inspection

[rbmgf7]

I've managed to conduct valve clearance jobs on numerous bikes without a problem but I managed to booger this one up.

I went to reinstall the cam towers to recheck my clearances since the exhausts were running tight but in the midst of torquing the bolts, the dowels got cocked and scrunched.

The holes in the cylinder head are pretty marred and the towers are crushed. Intake is fine.

[smg id=1926 type=preview align=center caption="20140930 200216 zpss2jvpspu jpg"]

Something tells me the proper way to fix this would be to remove the head and have a shop ream the holes for a proper fit.

 

[Koinz]

I've managed to conduct valve clearance jobs on numerous bikes without a problem but I managed to booger this one up.

I went to reinstall the cam towers to recheck my clearances since the exhausts were running tight but in the midst of torquing the bolts, the dowels got cocked and scrunched.

The holes in the cylinder head are pretty marred and the towers are crushed. Intake is fine.

[smg id=1926 type=preview align=center caption="20140930 200216 zpss2jvpspu jpg"]

Something tells me the proper way to fix this would be to remove the head and have a shop ream the holes for a proper fit.

Did you break the bolts on the two right side cam journals. It's kind of hard to see in your pic. If the towers are crushed, I'm not sure that's fixable. You may need a new head.

 

[rbmgf7]

I meant to say the dowels in the cam towers are crushed. No broken bolts.

Just putting this out there to see if there is some magical wonder tool I'm not aware about that could resolve this issue without having to remove the head.

 

[summitboy]

If the caps are damaged u most likely are screwed. The Yamaha heads are line bored from what I understand. They are on the 4 cyl genesis. If you need caps then you will need a head. Head is only 640 bucks which is pretty cheap. Maybe you can just get new dowels and retorque ??

 

[Checkswrecks]

I can't really see the damage well enough from your photo. It may be that if you replace the dowels with new ones, as a set they provide enough stability and alignment. I'm not sure any of us could say without actually feeling the fit.


As summit boy wrote, if the caps themselves are shot, then you likely have a bigger problem.

 

[yz454]

I can,t see for sure. but clean out the dowel pin holes with a fine edge scraper . get new dowel pins ,put it to together with out the cams and check if it torque s down all right.

 

[rbmgf7]

I think I might be fine but it sure is nerve wrecking.

[smg id=1927 type=preview align=center caption="20141001 174402 zpsnyduwlew jpg"]

[smg id=1928 type=preview align=center caption="20141001 174448 zpsdfhub2ku jpg"]

Don't know how I can squash those dowels. I was torquing at 7 lb-ft all the way. I was careful and walked the towers down gently, jumping back and forth between sides.

The caps are fine. It would be nice to ream holes and replace with some beefier dowels but I know trying to align the towers to the head after machining will be tough but not impossible.

I'd like to helicoil the tower fastener holes.

I'm this far already. Is there anyone out there that ports and polishes S10 heads? ::26::

 

[Koinz]

Take a small round file and clean up the holes. As suggested, get some new dowls . The cam surface looks ok. Gently tap the dowels in place.
install the caps without the cam first. Gently tap them onto the dowels with a plastic mallet to make sure they seat properly. If your satisfied with the fit, re-install the cam. Tap the caps on to get them started on the dowls again, then put the bolts in finger tight down the line until you get to the point you need to torque them.

I think you dodged a bullet. ???

 

[scott123007]

The dowels are supposed to be in the head, not the cap. From your photo, it appears they weren't. Make sure ALL the dowels are in the HEAD side first.

 

[rbmgf7]

The dowels are supposed to be in the head, not the cap. From your photo, it appears they weren't. Make sure ALL the dowels are in the HEAD side first.

Huh...ALL the dowels were in the caps. The majority of the dowel was pressed in the cap side with sbout a third sticking out to be pressed into the head side.

 

[Checkswrecks]

I expected and have fixed worse. Mask of the head to prevent contamination and as somebody else mentioned, just dress the holes as minimally as possible, replace the dowels, and you should be fine for another 26,000 miles.

Do measure the depth of each hole and of each dowel before starting re-assembly. I've seen a person (not me!) try to re-assemble with dowels that came from another part of the engine and which were too long.

 

[yz454]

I think your good to if you do what people suggested .

 

[EricV]

Take a small round file and clean up the holes. As suggested, get some new dowls . The cam surface looks ok. Gently tap the dowels in place.
install the caps without the cam first. Gently tap them onto the dowels with a plastic mallet to make sure they seat properly. If your satisfied with the fit, re-install the cam. Tap the caps on to get them started on the dowls again, then put the bolts in finger tight down the line until you get to the point you need to torque them.

I think you dodged a bullet. ???

::026:: Cover the head with rags or what ever, mask off the cam bearing surface and around the holes and clean them up as Koinz has outlined. A swiss pattern file in a rounded shape will give you good bite and they are small. Hopefully small enough to get in there and allow you to work. Resist any impulse to use power tools.

Normal dowel pins are solid. There may be various reasons these were not, what comes to mind first is that it may be an odd size, so Yamaha just made their own. This can be an engineering quirk, where someone re-invented the wheel instead of using off the shelf parts. You may be better off just ordering the Yamaha parts.

Why do you want to helicoil the head for the cap bolts? Did you also see damage to those holes? Typically aluminum parts only get helicoils for things that come off often. Unless there is damage, I would strongly suggest you do as little as possible and put it back together.

A good machine shop would put the head on a mill, and indicate in each hole, one at a time, then use a boring bar to clean up the mess w/o enlarging the hole. It's time consuming and I'd be using a finger indicator that read in tenths of a thousandth of an inch to be as precise as possible, then start with the boring bar undersize and sneak up to size in small amounts after removing the bulk of the aluminum swaged into the hole. Just digging out the bulk and stuffing a reamer in there is likely to result in an oblong hole or oversize one, or both.

 

[scott123007]

::026:: Normal dowel pins are solid. There may be various reasons these were not, what comes to mind first is that it may be an odd size, so Yamaha just made their own. This can be an engineering quirk, where someone re-invented the wheel instead of using off the shelf parts.

Eric, there is no mystery here. In almost every Japanese motorcycle cam cap that I know of, the cap bolts go THROUGH the dowels.

 

[EricV]

Eric, there is no mystery here. In almost every Japanese motorcycle cam cap that I know of, the cap bolts go THROUGH the dowels.

I've not played with motorcycle cams since the '40 HD back in the '80s. The more modern bikes I've had never needed me to go there. Interesting method, thanks for sharing the info! ::008:: Not something I've seen in Japanese automotive stuff.

 

[rbmgf7]

That was your mistake. Take all the dowels out of the caps and put them in the engine.

Where does it say in the manual that the dowels need to remain in the head?

If the majority of the dowel was in the cap, I would imagine that's how it's intended to be from the factory.

 

[Checkswrecks]

...caps through the dowels . . .

I've not played with motorcycle cams since the '40 HD back in the '80s. The more modern bikes I've had never needed me to go there. Interesting method, thanks for sharing the info! ::008:: Not something I've seen in Japanese automotive stuff.

???
Actually it's quite common.

 

[avc8130]

I've not played with motorcycle cams since the '40 HD back in the '80s. The more modern bikes I've had never needed me to go there. Interesting method, thanks for sharing the info! ::008:: Not something I've seen in Japanese automotive stuff.

I'm pretty sure your Tenere needs to go there now. ::024::

 

[EricV]

Funny AC. )

Maybe I wasn't paying attention in class. But then, I don't recall ever having any issues dealing with the cams/caps/etc. either. Used to pull a lot of Mazda cams for HLA replacement. Biggest horror stories were when the owner tried to do it themselves. The hilarious one was the guy that pulled the cam gears off, then re-installed and the car wouldn't run. Mazda puts both exhaust and intake timing marks on the cam gears, (they are interchangeable), he installed the cam gears in the wrong spot.

In regards to the dowel pins, I was actually reminded of the ones for the clutch cover. In manufacturing, one hole is press fit, the other slip fit. Made me wonder why Yamaha seemed to make them both slip fit in that area?

 

[Koinz]

It might not say it in the manual, but over the years it's always been advised to start with the dowels in the engine and not the caps. In your case if 3/4 of the dowel was indeed in the cap, this only left that small length of dowel to line up correctly before tightening the caps. This is of course where the problem reared it's ugly head, the dowels were not in the holes in the head. Now think what the difference would have been if the dowels were put in the head first. You push them in that small distance and now you have a dowel sticking up with ample area to insert the cap on the dowels at least a little way then tighten the bolts without fear of damage. Even if the dowel is same length in the head and cap, putting them in the head first always works better. Don't mean to be a know it all, as I could very well be wrong as maybe it doesn't matter on the Super Tenere. Good luck for sure. I think new dowels you should be good to go.

I agree 100%. The purpose of the dowel is to align the cap with the cam journal on the head. With the cam in place it's very hard to do this the other way around.... But I guess you know that now. 8)