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Discussion Starter · #1 ·
Hello all,

Happy memorial day weekend! Finally got around to changing my weeping 06 Bonny valve cover gasket.
New gasket, even got the better(brown) bolt gaskets. Got it all together, set tork wrench to just under 10 newton meters. Read enough war stories here to remember to be careful.
Yep, you guessed it!
#4 bolt stripped! I mean gone! I unscrewed alot of threat off of the bolt after removing.
What do i do next? How do you tap this? Is there a heli coil small to fit this?

All help will be greatly appreciated. Needless to say, no riding today!
Luckyman:(
 

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Happy memorial day weekend!
I can't help you with your valve cover problem but I would like to point out that there is nothing "happy" about Memorial day. We are honoring our military personnel who gave the ultimate sacrifice for the freedom to enjoy that burger & beer on this special day.
GO NAVY
 

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Helicoil is available for that, BUT you need to remove the cam cap from the bike before drilling it and installing the helicoil. You don't want to get any swarf into the motor, or caught in the cap to cam bearing surface.

Make sure to have a good quality torx set for removing the tower torx bolts. Lesser bits will snap and cause more problems.
 

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read sweet's link in my post. Its really easy...all you need is a thread kit, drill or drill press, lots of rags and the right torx bit.
 

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Torque Wrench Issue

Just got finished reading Help! Screwed Up! It seems everything was done correctly and the cap got stripped. My experience with torque wrenches is that you need to get them calibrated or mapped to be accurate. I got an inexpensive 3/8 in drive wrench and it was + 35% at the lowest range got to be right on at mid and - 25% at the highest range. I am lucky that I have a cal lab in work and was able to map 10 different points from min to max. My 25 year old 1/2" Craftsman was only out by about 5% from 10 to 80% of the range.

Mike
 

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Just got finished reading Help! Screwed Up! It seems everything was done correctly and the cap got stripped. My experience with torque wrenches is that you need to get them calibrated or mapped to be accurate. I got an inexpensive 3/8 in drive wrench and it was + 35% at the lowest range got to be right on at mid and - 25% at the highest range. I am lucky that I have a cal lab in work and was able to map 10 different points from min to max. My 25 year old 1/2" Craftsman was only out by about 5% from 10 to 80% of the range.

Mike
Just checked the Craftsman website. Even a new Craftsman torque wrench has a +/- 4% accuracy between 20 and 80% of the torque range for a specific wrench (error is greater at either end, as McBike notes above).

So, when one is dealing with ONLY 10 Nm, there is not much room for error before a bolt snaps. :eek: Good advice is not to use a larger capacity torque wrench when dealing with smallish torque settings ,as best accuracy is obtained in the middle of the range not at the ends.

. . . .I learned this the hard way years ago working for my Grandfather in his Farm Equipment Shop, been nervous with torque wrenches and grandfathers since then! :)
 

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There's plenty of room for error at 10NM. The thread was likely stripped when the screw was originally installed too tightly. Removing it was the kiss of death but didn't cause the problem.
 

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There's plenty of room for error at 10NM. The thread was likely stripped when the screw was originally installed too tightly. Removing it was the kiss of death but didn't cause the problem.
Didn't he strip the thread after he replaced the gasket?..All the factory equipment is pretested during assembly at Triumph and its highly unlikely it was caused at that time.
 

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:( I used a high quality Stahlwille 1/4 drive torque wrench, set at 9Nm, to tighten the rocker cover bolts on my Griso, and I still stripped the thread out of one. :( I had to get it helicoiled, and now tighten them to 7Nm, which works ok in this particular application. Steel bolts going into soft alloy always gives me the jitters.
 

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Discussion Starter · #14 ·
killian101
thanks for your response. i appreciate it!
Not to sound dumb, but how do i get to your post!
thx,
luckyman
 

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I used a high quality Stahlwille 1/4 drive torque wrench, set at 9Nm, to tighten the rocker cover bolts on my Griso, and I still stripped the thread out of one. I had to get it helicoiled, and now tighten them to 7Nm, which works ok in this particular application. Steel bolts going into soft alloy always gives me the jitters.
I take electronic / mechanical design prototypes from engineering and make them ready for high volume manufacturing. I always throw it back to them if they spec a stainless screw into an alloy piece part. My requirement is that a steel screw needs to go into a helicoil.

Mike
 

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Discussion Starter · #16 ·
McBike,
I think your right on the money with this one! My son bought me this torque wrench from sears 2 years ago. I never thought to have it checked for calibration! I know I had it set correctly!
The local Trumpet shop,45 miles away said maybe can fix or buy a new $1300 head! Not in this life! I have a local performance shop who said no problem without hesitation and who I trust! YEP, time to have the ol "T" wrench calibrated!
 

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Didn't he strip the thread after he replaced the gasket?..All the factory equipment is pretested during assembly at Triumph and its highly unlikely it was caused at that time.
If he tightened to 10NM and it stripped, then it's highly likely that the thread was already compromised. They don't necessarily go from strong and clean as a whistle to total failure in one step.
 

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First, if the links to the other posts haven't covered it already and if luckyman still need to complete his repair I'll just offer that when removing the cam holder to perform the helicoil work he'll likely find the torx head screws on the cap holders to be profoundly tight. Get a good solid tipped T30 bit fitted well, straight and true into the screw-head when loosening them. Also as Propforward posted in the one link, ensure the cams are in the upright position for the least strain on the camshaft if only removing one cam holder for the repair.

Secondly I'm just going to comment that I seem to read TOO many posts about folks stripping these threads out. It is not possible for me to determine if there are just that many careless 'mechanics' working on their bikes but certainly luckyman and many others have done what they should have done to prevent an issue like this. It seems to me that maybe there is a design flaw. Tolerances on the low end of a torque wrench should really NOT be a big enough factor to cause failure on a well engineered product. Sure its good advice to use a small scale calibrated tool. But a well engineered product will have a fair amount of allowance between the failure limit and the spec limit. A 1.5 factor of safely is not too much to ask.
I'm not saying that the Bonnie's are not well engineered, in fact all in all they seem to be VERY well engineered. Its just these few things that keep coming up that I wonder about.
 

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the main reason the bolts strip is the bolt sholder bottoms out on the cap when tight the treads being the weak link.What I do is forget the torque wrench on the vc bolts use a short allen wrench ,you can feel when the bolt bottoms out on its sholder it does not have to be any tighter then that to seal the gasket just snug on the sholder.I have had the valve cover off maybe 100 times with no troubles striping bolts.
 
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