Bolts 101

[dwire]

I have no idea how many times I have explained this, but here goes again.

I would estimate that of the leaks, broken fasteners, parts fallen off and stripped out holes, 90% were due to being over tightened.

In most cases it is better/cheaper to err on the side of under torque.

We made a lot of money from over tightening and a little on parts that fell off.

It is your bike, do as you wish. The BMW isn't a Brit bike, relearn mechanical principles and save your BMW.

Yes, I know you have...

I was trying to illustrate myself to others the very same thing. The highest priority when setting torque specs for a product by any maker is liability. Guess which way the figures always end up? You guessed it if you said always on the high side... If they are not, someone likely was not following orders/procedure when they set the spec or simply made a mistake.

[Deleted User 61]

Brad, if you are using the 26 11 1 230 414, 14mm fasteners with the lock washers, QUIT!
Use 26 11 1 242 297, it is a 13mm fastener without a lock washer.
This has been discussed here so many times, I can't believe you haven't seen it.
The lock washers have been known to break, and when they do, the fastener comes loose, and that is not a good thing. Which is why BMW quit using the 14mm w/washer. According to my R65 parts catalog, they started the 13mm with the '81 models.

According to the guy at Lonestar BMW, the bolt is a simple Stainless Steel bolt and it was used by BMW for only two years. Most airheads have shorter bolts.

I looked at two R65s motors at Airhead Salvage and both had this kind of bolt. The bolts are not supposed to be changed each time, but the wave washer is. I have ordered a set of both. Another week on the lift.

[bbelk]

Brad, if you are using the 26 11 1 230 414, 14mm fasteners with the lock washers, QUIT!
Use 26 11 1 242 297, it is a 13mm fastener without a lock washer.
This has been discussed here so many times, I can't believe you haven't seen it.
The lock washers have been known to break, and when they do, the fastener comes loose, and that is not a good thing. Which is why BMW quit using the 14mm w/washer. According to my R65 parts catalog, they started the 13mm with the '81 models.

Well thats just dandy. I don't speak bolt well enough to know what I am getting, so I guess I will call Lonestar which is of course closed until Tuesday. I may get this bike back together before summer......

Anyway - I assume I should order the bolts from a later model? Why not just leave the washers off. Whats a mm. The washers are paper thin. Is there an interferance problem?

[Frog]

I have no idea how many times I have explained this, but here goes again.

I would estimate that of the leaks, broken fasteners, parts fallen off and stripped out holes, 90% were due to being over tightened.

In most cases it is better/cheaper to err on the side of under torque.

We made a lot of money from over tightening and a little on parts that fell off.

It is your bike, do as you wish. The BMW isn't a Brit bike, relearn mechanical principles and save your BMW.

This is a funny discussion. One of my good friends is a former BMW mechanic and he has recently helped my out on the bikes that I am working on. He was surprised by how little I tend to tighten things. But in most cases* we agreed that my system works fine, as the bolts in question never come loose.

*the only exception to this is that I used to do my valve adjusts without torquing the heads. After a few years, my cylinder bases started to weep. Now, I check them once in a while and all is well.

Feel comes with experience, torque wrenches are a good way to stay out of trouble.

[Deleted User 61]

Brad, if you are using the 26 11 1 230 414, 14mm fasteners with the lock washers, QUIT!
Use 26 11 1 242 297, it is a 13mm fastener without a lock washer.
This has been discussed here so many times, I can't believe you haven't seen it.
The lock washers have been known to break, and when they do, the fastener comes loose, and that is not a good thing. Which is why BMW quit using the 14mm w/washer. According to my R65 parts catalog, they started the 13mm with the '81 models.

Well thats just dandy. I don't speak bolt well enough to know what I am getting, so I guess I will call Lonestar which is of course closed until Tuesday. I may get this bike back together before summer......

Anyway - I assume I should order the bolts from a later model? Why not just leave the washers off. Whats a mm. The washers are paper thin. Is there an interferance problem?

mm = millimeter. 1/1000 of a meter (a little longer than a yard).

If you just "leave the washers off", there will be a interference problem. Tolerances in their are very close, I have read, here. Apparently the washers are 1 millimeter thick, hence, the shorter fasteners for use without washers. I think long 14mm fasteners w/o a washer will have the tip of the fasteners rubbing against the output seal. (right, guys?)

[dougie]

If you just "leave the washers off", there will be a interference problem. Tolerances in their are very close, I have read, here. Apparently the washers are 1 millimeter thick, hence, the shorter fasteners for use without washers. I think long 14mm fasteners w/o a washer will have the tip of the fasteners rubbing against the output seal. (right, guys?)

If they went to the trouble to make them 1mm shorter, I am sure there is a reason. For what they cost, why gamble?

[George Ryals]

If the bolts you ordered come in 14 mm, just carefully grind off 1 mm. They WILL hit the trans case if you use the 14 mm bolts with no washers.

[bbelk]

Can anyone tell me with any certainty that the simple looking stainless steel bolt that I need is in any way other than size, "special". There is a picture on the original post.

Is it harder or softer or stiffer or anything than a stainless steel bolt the right size from the local bolt store.

I am tired of waiting for parts to come in.

[George Ryals]

OOPS! For some reason I thought the thread had shifted to trans output flange bolts with the discussion about lockwashers being deleted as time went by. Sorry!

[Deleted User 61]

OOPS! For some reason I thought the thread had shifted to trans output flange bolts with the discussion about lockwashers being deleted as time went by. Sorry!

You mean we are not talking about drive shaft flange screws?
I guess we are talking about clutch screws?
I still buy OEM, so I don't have to worry about it.

Give Matt a call, or Hucky's. Hucky's keeps an amazing amount of stuff in stock. When I order from him (via email) on a Sunday, I have it before Friday.