So I guess I知 replacing the head

[Guest]

More than I anticipated doing on this bike but there are 6 broken exhaust bolts in the thing. I spent about 3 hours trying to clear one of them with little success. They are seized up hard. Went thru all the tips on the forum about bolts and tools and I知 moving on. I値l feel better about the bike anyway once I know what痴 in there, especially given some of the things I致e come across from the PO.

So 1. If the site has a thread or tips on the process, please share. This is my first one.
2. Any gotchas I need to know about, also please share.

Thanks

[Nessism]

A machine shop can extract the bolts. In terms of DYI, I've had good success using LH drill bits, but doing 6 will try patience.

[Dan]

Thanks Ed. I tried the LH bits, extractors, torch, penetrating spray, voodoo curses. I'll look around some at machine shops too. Dan

[Nessism]

Harbor freight has a cheap LH bit set. Start with one of the smallest sizes and center punch the bolt before drilling. If you are off center work the bit sideways a little and get in the center as you step up the size. Slowly, one size then the next, being sure to work towards the center and then stay there as the bit size grows. Eventually you will be near full diameter of the broken screw and when the screw is just a shell it will grab on the bit and spin out. Works every time as long as you are careful.

[GregT]

Find a good TIG welder. I have one local to me who can weld a bolt with a point on the end onto a broken bolt or stud - so long as the end is visible.
The heat of the weld expands the aluminium away from the broken piece and it simply winds out...

He must have done over a hundred for me over the years now.

[Dan]

Thanks for the tips. Some of the breaks are beneath the surface. If the threads are damaged am I looking at helicoil or is that a bad idea?

[GregT]

Thanks for the tips. Some of the breaks are beneath the surface. If the threads are damaged am I looking at helicoil or is that a bad idea?

Helicoils are fine for exhaust studs.

[Dan]

Ok - decision time.

In addition to several broken exhaust bolts, I've found that the PO had tried to drill out one of them to the point that the hole is now larger than the bolt so a bolt just slides in and out of it. It will need helicoil, if it's salvageable at all.

I now see at least 1 intake screw broken, and several others that look completely rusted in place and are likely to break.

I am having no luck getting any of these out. Prior post about that misadventure.

I don't have the ability to take the complete bike to a shop. I was considering buying a new (used) head with valves already in place.

Valve cover is off. Actually pleased with the appearance of the cams from what I can see (photo below.)

So it seems I can either...

(1) continue was planned, pull the head, find a new head w valves, replace.
(2) pull the engine, take it to a shop for the bolt/helicoil problem.

I'm a bit intimated by taking the head off, but that's where I'm leaning.
I'm also intimidated by pulling the engine, since I'm doing this alone and I'm fond of hernias.

Any thoughts would be appreciated. Thanks


IMG_6099.jpg

[Big T]

You don't need to pull the engine to pull the head.
But, when you pull the head, pull the barrels and replace the base gasket and the two O rings

Many people replace those exhaust bolts with studs.
You can Helicoil that one bad hole, but a threadcert would be better.

I will advise you that you probably will find more Previous Owner Syndrome as you go thru the bike

[Dan]

Thanks. Never heard of a threadcert. I assume that's a "thread insert." https://www.grainger.com/category/fa.../thread-insert

I'll learn about pulling the barrels. I have the opportunity to learn a lot looks like.

[Dan]

You were right. I found other PO issues, including what looks like household silicone applied around the base gasket. This in addition to a wood screw holding on an exhaust pipe, which I posted about on another thread.

Pulled the head. Will pull the barrels to get to the base gasket and replace that, but I've never done that. A couple of questions -
Does that lower unit just lift up? It looks like it's held in place by the same studs as the head?
What happens to the pistons when I do that? I assume they stay attached to the camshaft, but how do I get the lower unit back on given the rings?
Newbie questions I know but I've looked around and I don't see a procedure.

Thanks, Dan

[Big T]

Yes, the cylinder barrel pulls up on off.
Hopefully, the rods and pistons are attached to the crank shaft.

There are several techniques for getting the barrels back over the pistons. I prefer some wood blocks and hose clamps.

You downloaded a service manual yet?

[Dan]

Thanks, the rods and pistons appear to work as I manually turn the engine.
I have downloaded a service manual but haven't dug into it yet. Thanks for the suggestion. I'll focus on reassembly after I clean up everything.

Here's a shot of the silicone job. Goes around the whole base, but it didn't stop an oil leak from the front.

IMG_6118.jpg

[cowboyup3371]

That bunch of slop is someone's feeble attempt to put a cheap gasket on and yes, it's useless. Although they are expensive, I recommend buying the proper OEM head and base gaskets and ensuring everything is set correctly. You will want to use wood blocks to support the pistons when installing the head - there are threads here about using them and I will try to to see if I have any pictures otherwise I'll get some this weekend.

[Big T]

You may luck out and find that all of that silicone is external.

Just when you think you've seen it all