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General Category >> Rubber Side Down! >> Broken Cover Head Bolts during Oil Leak Fix
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Message started by JoophJoobie on 04/02/17 at 00:24:45

Title: Broken Cover Head Bolts during Oil Leak Fix
Post by JoophJoobie on 04/02/17 at 00:24:45

I was fixing the infamous oil leak today. After I installed the plug with sealant, tried to torque the head cover bolts in and broke three of them. I had the torque set at 6 ft lb, the lowest recommendation. Kept wrenching until, POP, there goes the bolts. They are broken mostly at the top of the thread.

The three bolts I broke are the L60, L125, L130.

L125 and L130 are pretty long. Has anyone had any experience drilling them out?

Any advice would help. I'm going to take the headcover off tomorrow and check out if anything is do able.

Title: Re: Broken Cover Head Bolts during Oil Leak Fix
Post by Dave on 04/02/17 at 03:53:27

Sorry that this happened - unfortunately, I don't think there is an easy fix. Where you using a 150 ft/lb click torque wrench? It is nearly impossible to get a good "click" at low settings - my 150 ft/lb wrench is difficult to get to work well at anything below 50 ft/lbs.

I believe the only way you can fix this - is to take the engine out of the frame and remove the head. The 130mm bolt extends down through the head and into the cylinder.....and there is an oil port surrounding the bolt. Any metal shaving you create will be routed to the cam and rockers.

Here is a thread where a fellow stripped the aluminum threads on the 130mm bolt.....this thread could well lead to some of this discussion.
http://suzukisavage.com/cgi-bin/YaBB.pl?num=1365422652

This thread has photos that shows the oil galley where the 130mm screw enters the cylinder.
http://suzukisavage.com/cgi-bin/YaBB.pl?num=1448209911/0#0

Title: Re: Broken Cover Head Bolts during Oil Leak Fix
Post by justin_o_guy2 on 04/02/17 at 07:15:19

Don't use a torque wrench. Use a 1/4" ratchet and just use your hand, thumb on the ratchet head, and just close the fingers, you can Feel the bolt tell you it's tight.

You're lucky, bolts broke. That's much better than stripped threads in the head.
You might have to pull the head cover..
For future reference, if you're ever doing anything and you break a bolt, it's time to think about your approach.

Title: Re: Broken Cover Head Bolts during Oil Leak Fix
Post by Dave on 04/02/17 at 07:28:34

It depends on how far down the 130mm bolt broke if removing the head cover will do any good. If the bolt is broken down below the head cover, I don't believe drilling is an option.

Title: Re: Broken Cover Head Bolts during Oil Leak Fix
Post by justin_o_guy2 on 04/02/17 at 09:33:34

Anyone who is so inexperienced as to break three is not likely to be successful in removing the dutchmen. With the head cover on, I couldn't. If they're snapped off flush with the head, he might win. They Should turn easily enough. Sounds like left hand bit time. Or, haul it to a machine shop.
Do you know anyone who is an experienced mechanic or machinist?

Title: Re: Broken Cover Head Bolts during Oil Leak Fix
Post by JoophJoobie on 04/02/17 at 12:51:45

Thanks for the advice. I was using a 150 ft.lb torque wrench. I used a ratchet the first time I put the head cover back together, but after reading some threads people advised to torque them to the correct values. I didn't know about inch to lb wrenches so lesson learned.

This is my first bike and I'm trying to learn as much as I can. I'll take the engine out and take a look at the head. I'll take it to a shop if the job looks over my head.

Title: Re: Broken Cover Head Bolts during Oil Leak Fix
Post by twhitus on 04/02/17 at 12:54:43

Broke a valve cover bolt once because i mixed up my in lb wrench with my ft lb wrench. I got a much smaller bolt and put a little bab of liquid steel on it, let it dry and it came out easy enough. Just a thought as the threads dont hold the torque usually.

Title: Re: Broken Cover Head Bolts during Oil Leak Fix
Post by justin_o_guy2 on 04/02/17 at 13:25:06

I've pulled the head cover twice. No leaks, nothing messed up, nothing but a 1/4" ratchet, patience and a gentle touch.

Title: Re: Broken Cover Head Bolts during Oil Leak Fix
Post by Armen on 04/02/17 at 19:28:24

Hey Jooph,
Easy mistake. Understand that a torque wrench is a measuring tool. Analog meters and torque wrenches are most accurate in the top 90% of their range.
Translation? Let's say you had an analog voltmeter, and wanted to measure voltage. You wouldn't use a 0-1000V meter to read 2 volts. The needle would barely come off the peg, and your readings would be inaccurate. Same thing with torque wrenches. I usually tell my students to get two torque wrenches-one that goes to the highest torque spec on the bike (on most bikes that is around 100 ft/lbs), and an Inch Pound torque wrench that will go down to 40 inch lbs, and up past the lowest setting of their bigger wrench (I.E. smaller one goes to 20 ft/lbs, bigger one starts at 10 ft/lbs).
Just like helmets are cheaper than brain surgery, torque wrenches are cheaper than having busted bolts removed.

Title: Re: Broken Cover Head Bolts during Oil Leak Fix
Post by Dave on 04/03/17 at 04:08:29

Can you show us a photo of the bolts that broke?

How far down did they twist off.....my guess would be that the weak spot is where the threads meet the smooth portion - I would think that is a weak spot....but I don't know for sure.

Title: Re: Broken Cover Head Bolts during Oil Leak Fix
Post by stewmills on 04/03/17 at 13:39:02

I've never done this, so disclaimer has been noted...but why wouldn't the easiest method be drilling out a small hole in the bolt, tapping it using a left-hand thread tap, then using a left-hand bolt to tread down in there an then "keep turning counterclockwise" to back the bolt out.

I've never done one of these, but that seems like it would be my first choice with my limited knowledge and experience.

Title: Re: Broken Cover Head Bolts during Oil Leak Fix
Post by Dave on 04/03/17 at 13:54:18

Stew:

One of the issues is that the right rear bolt is 130mm long, and it goes into the oil galley that routes the oil up to the head.....if you get any metal shavings in the hole while your drilling/tapping - those metal shavings will be pumped up to the cam and rockers.

The other problem is that that same bolt is 130mm long...most likely there is 15mm or so of threads - which means the part you need to drill and tap could be 115mm down the hole if the bolt broke near the bottom - so you have to get 4.5 inches down the hole! Even if the bolt broke off somewhere near the top - the drilling/tapping could make metal shavings where you don't want them.

I think a critical part of this repair is knowing how far down the bolts broke....we still haven't got an answer to that question. If the bolts broke up near the top - removing the head cap may get you access to the stub of the screw.....and since the head is gone and the tension is released - they could possibly be unscrewed pretty easily.

Title: Re: Broken Cover Head Bolts during Oil Leak Fix
Post by stewmills on 04/03/17 at 13:58:32

That makes sense. I'm just optimistic thinking it just snapped the head off and the break is right there near or at the surface, but that seems to not be the case with most of these situations. Hope I never have to learn how to do this :-?

Title: Re: Broken Cover Head Bolts during Oil Leak Fix
Post by verslagen1 on 04/03/17 at 14:26:40

If you've just snapped the head off, the failure could be anywhere along bolt.
But usually where the threads begins.
So, measure the stub remaining on the head and give us the measurement.
Then we'll know how far down sh!t creek you are... watch out for the falls.

Also, when a bolt breaks sometimes once the tension is off it easy to turn.
So, find a piece of tubing and glue it to the piece that broke off.
The head cover has a small hole but once that's off, the hole is larger for the oil flow.
Add some more glue and push it on to the broken piece, if there's a stub left on the threads of course.