Need tips for removing the head...

[hikermikem]

1981 750L 16V engine.

Yesterday's posts here have described my battle with a broken exhaust bolt, and subsequent futile efforts to remove it. Time to move on & let a shop take it from here, or I will just continue to make it worse (if that's even possilble).

I have a downloaded service manual but the quality is poor & most of the highlighted notes & pics are not very discernible.

The section on head removal essentially states:

- Remove cover
- Remove cam chain tensioner
- Remove both cams
- Remove cam chain guide
- Remove (3) 6mm bolts & (12) 10mm nuts
- Remove head

My main question(s) concerns the timing chain:

- Do you leave it attached in a big loop or do you have to take it apart?
- How do you keep it from dropping down into the engine?
- Is re-timing after re-install difficult?
- Do I need to replace the head gasket as well?

I know, noobie questions, but I haven't ventured here yet so this will be a learning experience (a GOOD one I hope).

Thanks for any & all advice,

Mike

[robertbarr]

I used a length of #14 solid electrical wire. Fasten it to the cam chain (after pulling the tensioner). When you remove the head, you'll pull the head off of the protruding wire. This way your cam chain doesn't irretrievably drop into the case. It's really no big deal.

Reassembly / timing is a different matter. It's not difficult, but I've never done a 16v engine, so I'll leave that to someone who has. Your manual will surely have a fairly detailed description of the process.

[Nessism]

When removing the head it's advisable to pull the cylinder off as well to replace the base gasket. If you are going to do this, there is no need to tie the cam chain up since it's easy to grab with the cylinder off.

Next obvious question may be if it's necessary to remove the cylinder. Answer to that depends on how lucky you feel. It might be fine, or it may leak. Based on how things when with your exhaust removal experience...well, you be the judge.

Good luck Mike.

[hikermikem]

When removing the head it's advisable to pull the cylinder off as well to replace the base gasket. If you are going to do this, there is no need to tie the cam chain up since it's easy to grab with the cylinder off.

Next obvious question may be if it's necessary to remove the cylinder. Answer to that depends on how lucky you feel. It might be fine, or it may leak. Based on how things when with your exhaust removal experience...well, you be the judge.

Good luck Mike.

Thanks Ed,

The bike has 17K on it, but I got it as a non-runner so I don't know its history...

The head gasket area has a lot of gunked up oil in the front but I'm not completely sure it was leaking - the cam chain tensioner "area" also was VERY gunked up with oil & grunge. I was thinking perhaps the cam chain tensioner had been leaking for a while & the oil found its way to the front of the engine through the hollows between the cylinders. I rebuilt the tensioner while I was doing the carbs & replaced the seals & o-rings in it.

I also adjusted the valves as well...

The base gasket area looks clean, & I don't want to go that far at this time - maybe that will bite me, but I will leave that project for another day!

I believe I should do a compression check at this point to determine the relative health of the valves (rings?) before the head removal.

With 17K I don't think too much can be worn...

Thanks,

mike

(BTW - I was out in LA a couple of weeks ago but didn't have any time to give you a call, maybe next time)

[mike_of_bbg]

A compression test is not a bad idea. It will give you at least some idea of the relative health of the motor. Doing both wet and dry tests will help determine the health of the rings. Because your bike isn't running you'll have to do it cold, so the numbers may seem a bit lower than you'd hope for, but should improve on a warm engine. Make sure to hold the throttle open when you run the tests! In my case a compression test helped me find out that my crankshaft was twisted.

Lots of wear can happen in 17k miles depending on how the engine was treated. That is, if 17k is the actual mileage.

[Hank.SD]

Mine is an 1100 so this isn't probably completely relevant, but I just had the head off mine to solve a major head gasket oil leak, and while I was in there I decided to do the base gasket and then re-ring.

My motor has 20,400 miles on it, and the cylinders were well within spec on bore and roundness. I just honed and ringed.

I also did valve seals, just because they're so old, not because I had a problem. They were surprising pliable once I had them out, but the new ones "gripped" the valves much better.

[hikermikem]

Thanks guys,

Well, I suppose a case can be made to keep digging and replace everything old... I'll need to plant another money tree.

However, at this point I think I will just get the head sorted out, replace it & ride the bike for the season. Then I can make an educated assessment of any & all issues (if any) that might need attention.

With 17K on the clock I'm thinking she can't be in too bad of shape, but of course who knows...

I removed the head this afternoon & now I need to locate a machine shop to drill out my boo-boo.

Hopefully in a week or so I can start this thing!

Mike

[hikermikem]

Broken exhaust bolt update

When removing the head it's advisable to pull the cylinder off as well to replace the base gasket.

I removed the head yesterday and, on the advice of a friend, took it to a local guy who welds & runs a machine shop out of his garage. He welded a bolt onto the broken one that was sheared flush with the flange and after a couple of tries, the broken piece threaded out ! .

So now I got to thinking more about Ed's recomendation of replacing the base gasket - yes, I guess that's the prudent thing to do and in fact, I've already ordered new OEM gaskets & o-rings.

I decided against replacing rings & such because I did a compression check before pulling the head & all clyinders were over 170# (actually #4 was 185#). Good to go for for now...

Although this little excursion set me back a bit, I'm hoping to get her running in a week or so...

[Larry D]

I'd be very interested in some pics, Mike..............

Unless there's a designated picture taker, I get busy and focused on what I'm doing, and forget to pick up the camera.

[hikermikem]

I'd be very interested in some pics, Mike..............

Unless there's a designated picture taker, I get busy and focused on what I'm doing, and forget to pick up the camera.

Yes, like you i get all wrapped up in the project & only later think I should've snapped a few pics!

The bolt hole with the broken combo bolt/extractor was quite ugly indeed; couldn't even tell there was a hole there after I got done with it. The welding scheme worked VERY WELL & didn't mess up the aluminum at all.

I hope I don't have to do that again though !

[RyanBiggs]

...and getting that cylinder block off...

This is a timely post for me too, because I have a related call for advice. Some of you may remember me from the "Cylinder Head is off, Now What?" post from a couple weeks ago. I finally got some help around and decided it was time to tear in, but I can't get the stinkin' cylinder block loose!

I'm assuming that there are some of those press-fit locating dowels like the ones that locate the head on the cylinders. Perhaps one of you could confirm or deny that, and specify where they are. The Haynes manual mentions something about the front outer studs, but I don't see anything there in the photos. Firm pulls aren't doing it, and there's practically nowhere to hit the thing to tap it off. Moderate taps on the one reinforced area (front top center) didn't seem to be doing much, so I was trying to tap gently with a block of wood and rubber mallet around the base. I got carried away and managed to knock out a chunk of fin, duh. Should have known better, I've seen how brittle these castings are...

Any info/suggestions? Or cosmetic fin repair tips, LOL?!

[Hank.SD]

Glad that worked for you... I welded nuts on all four of my broken studs and I still couldn't budge even one of them!! They just broke again.. after a week of soaking.

[Nessism]

I removed the head yesterday and, on the advice of a friend, took it to a local guy who welds & runs a machine shop out of his garage. He welded a bolt onto the broken one that was sheared flush with the flange and after a couple of tries, the broken piece threaded out ! .

So now I got to thinking more about Ed's recomendation of replacing the base gasket - yes, I guess that's the prudent thing to do and in fact, I've already ordered new OEM gaskets & o-rings.

I decided against replacing rings & such because I did a compression check before pulling the head & all clyinders were over 170# (actually #4 was 185#). Good to go for for now...

Although this little excursion set me back a bit, I'm hoping to get her running in a week or so...

Hey Mike,

What about the valve seals? Sorry for the guilt but seriously, you should do them while the head is off. And check the head for flatness while you are at it. Oh, and don't forget about...just kidding.

[hikermikem]

Hey Mike,

What about the valve seals? Sorry for the guilt but seriously, you should do them while the head is off. And check the head for flatness while you are at it. Oh, and don't forget about...just kidding.

Yer killin' me...