Con Rod bolts

[K2-K6]

As you've said a good discussion, I like to find out about something with real reasoning behind it.

I suppose that logic dictates that cost although a consideration cannot control what has to happen in a technical sense as if they break then the cost saving will become irrelevant.

With that in mind, if you ran a dealership and could replace the bolts at the customers cost and not run the risk of the customer coming back to you with a  broken motor then I guess you'd always advise that path as a default but it doesn't answer the question of re-use from a specification point of view.

Mark Paris would be hard to argue against though as he seems to be right in the thick of these motors.

Assume you can get original Honda bolts or verified better spec. Safest option is to change them as nobody can definitively answer the original question.

[AshimotoK0]

Personally I would go with what Hondaman says if its the first strip down. I thought 'Stretch' bolts were the type where you tighten and keep measuring the length to a stated length, thus tightening to the correct torque. Don't forget that Bryan worked at a Honda dealer too!

Cheers

Ash

[Voxonda]

Always follow your own instinct, wether good or bad. Let keep it at that.

[Bryanj]

The "Old" Hondas were not designated as "Stretch" bolts, just done up to a torque which, in theory at least, is well within the elastic limit of the metal.

The only motorcycle bolts that were done up to a stretch were the old (pre-unit) Triumphs and believe it or not that was because micrometers were more common than torque wrenches(accurate ones that is) when the bottom end was designed.

ALSO BEWARE that a lot of torque wrenches are aonly +or- 15% of the indicated torque,

Snap on are +or- 10% for a torque wrench and +or- 5% for a torque meter

[UKROBK7]

My gut feeling was to change the bolts as at least all you have done is possibly waste a relatively small amount of money compared to trying to salvage an engine!  The information from Mark Paris is what I have always done on early British bikes when spares were difficult to get (bit different now there are specialists) and makes sense.  The article in a 1976 Motorcycle Mechanics magazine that I have found also says "No need to change the bolts".

The decision has been made for me as today a surprise parcel arrived with 8 bolts.  This was courtesy of my wife!  She says "stop messing about and get them changed, you know you will be happier".    Women !!

Rob

[Voxonda]

Again proof that we have to listen to women more!

[AshimotoK0]

Did I tell you about the time I got home and found my wife hammering in a wall nail with a CB750 con rod she found next to my computer! luckily it was from a scrap engine