Heli-coil/Timesert question

[seestheday]

Looks like I have a stripped thread on one of my valve cover bolts which is what was has been causing a slight oil leak since I've owned the bike.

Any tips on the upcoming heli-coil I will be doing?  Do I need to pull the engine?

[Piute]

http://honda-cb750-s.456789.n3.nabble.com/1980-CB750F-valve-cover-bolt-stripped-plz-help-td458245.html

[Re-run]

I guess it depends on where the insert is needed or if there is clearance. I would say most of the front bolts would be fairly open to access. rear might be a different story.

[shinyribs]

Can you get the valve cover all the way off on a DOHC. I know a SOHC won't come off. If the cover will come out of the way I would imagine you could get to it ok with a tap,but drilling it out takes a lot of clearance.Man,I hope you can do it in frame.You'll just have to try and see.Best of luck to you

[rrgunslinger]

I drilled and taped.  Get a high quality drill bit and tap and go slow when drilling.

Harvey

On Apr 22, 2012 9:56 PM, "seestheday [via Honda CB750'S]" <[hidden email]> wrote:

Looks like I have a stripped thread on one of my valve cover bolts which is what was has been causing a slight oil leak since I've owned the bike.

Any tips on the upcoming heli-coil I will be doing?  Do I need to pull the engine?

1981 CB750K

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NAML

[Re-run]

On the dohc you can get the cov er off with engine in frame. You can on the sohc A bikes too.Thats why frame kits are so damn nice to have! I will have one, oh yes I will.

[shinyribs]

The removable upper tube kits? yeah,they're nice. If you would,let me know if you find a good deal on one. I need two actually!

[seestheday]

Gunslinger, what size helicoil did you use?

I was planning on pulling the bolt and going to a hardware store tomorrow to figure out the exact size/thread pitch etc, so I can buy the right helicoil kit.

bikebandit tells me it's a 6x37 bolt, but that isn't enough info (http://www.bikebandit.com/houseofmotorcycles/1981-honda-cb750k/o/m2003#sch31465).

Oh, and I can definitely get the valve cover off while it's in the frame.  I have to do that to check the valve clearances.

[Lucky 1]

You do not need a time sert.  You do not need a helicoil.

You can go to a good auto store or machine shop and get the stud with the next size larger threads
on the end that goes into the head and the other end is still 6mm. Common
Just retap and use red Locktite. Time serts are used on bolts that are going to be taken in and out on a regular basis. Like spark plugs.

One more thing.. The size of tap and drill problem. When you buy the TAP many times the package tells you the drill size, and sometimes the tap and drill are sold together.
IF all of that fails just go to Google and type in "TAP drill chart".  LUCKY

[seestheday]

I do need to take the valve cover off once a year to do a valve check/adjustment.  I'm guessing that isn't often enough to justify using a heli-coil.

I'll look into getting the next size bolt.  I have not been impressed by the local auto-parts stores here.  They don't seem to be as good as what you guys have down in the states.  I might need to order the bolt online, and pay through the nose for shipping.

[Lucky 1]

You do not need to remove the valve cover to do a valve adjustment.

You only need to remove the tappet covers. Thats it.  LUCKY

[seestheday]

I have a dohc (see my sig). The procedure per the fsm is to remove the valve cover to check valve clearances.

Sent from my BlackBerry device on the Rogers Wireless Network

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From: "lucky [via Honda CB750'S]" <[hidden email]>

Date: Tue, 24 Apr 2012 14:15:01 -0700 (PDT)

To: seestheday<[hidden email]>

Subject: Re: Heli-coil/Timesert question

You do not need to remove the valve cover to do a valve adjustment.

You only need to remove the tappet covers. Thats it.  LUCKY

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NAML

[TOOLS1]

Your DOHC uses a special bolt, and washer with a gasket. The stud would not work right, and would leak. Go with the Heli-coil.
TOOLS

[seestheday]

Ya, I figured that out as soon as I took the bolt off. Now way a larger bolt will work. I bought a heli-coil.

Sent from my BlackBerry device on the Rogers Wireless Network

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From: "TOOLS1 [via Honda CB750'S]" <[hidden email]>

Date: Tue, 24 Apr 2012 15:15:25 -0700 (PDT)

To: seestheday<[hidden email]>

Subject: Re: Heli-coil/Timesert question

Your DOHC uses a special bolt, and washer with a gasket. The stud would not work right, and would leak. Go with the Heli-coil.
TOOLS

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NAML

[seestheday]

Well, I took the valve cover off and found this mess.



Scared me a bit because I thought it might be catastrophic and that I'd need a new engine.

It all worked out though.  I fished out all of the broken pieces, drilled, tapped and installed the heli-coil.  I put it all back together and the bike is running great.  

Now I just have to get the air/fuel mix right and seal the exhausts.

[shinyribs]

Wow,that a full house! I'm glad it worked out for you.It's never as bad as it seems at first,is it?