clutch spring bolts

[queenmonkey]

Some of you may be aware of my other thread re gear change rod. Well i've stripped out the clutch hub and now put it back on. When tightening up the clutch spring cover one of the bolts snapped - didn't tighten it very much but it broke. Well i got a new clutch hub, took the old one out, and what do you know another bolt has snapped! The hub is still on but has a broken thread in it (along with the old one). Presumably i'm not going to get away with leaving a spring/ bolt out? I'm seriously thinking of breaking the bike now as it seems doomed. Should these break so easilly? Should i have left than tight with a t bar and no tighter?

[allojohn]

Sorry bud, that's a pain in the rear. These bolts should be tightened to about 4 ft lbs - that's all. You really need to use a torque wrench.

[tkent02]

And use new bolts, apparently some previous bone head PO over tightened them.

[queenmonkey]

torque wrench

I am using a torque wrench set to 8lbs and they're snapping before i'me getting near that! I'm now on my third hub centre and going to discard with the wrench and leave them tbar finger tight.
QM

[hampshirehog]

Throw the torque wrench away and learn how to do things up by feel - I can't believe how many people break stuff / strip threads using a torque wrench.

There's a few times the torque wrench comes in to its own. Make sure it's properly calibrated and you know how to use it. You don't need it for clutch bolts.

[allojohn]

Throw the torque wrench away and learn how to do things up by feel.

HH, some of us amateur mechanics need all the help we can get.

[hampshirehog]

The trouble is that a torque wrench is only as good as it's been manufactured, tested and looked after. If none of that is spot on they are useless or worse than useless. And the lower the force needed the worse they are.

Spanner design works pretty well to help with roughly setting the right torque for a bolt - an 8mm spanner is maybe 10cm long whereas a 20mm spanner is about a foot long (rough estimates - I have never measured them). More leverage for the same pressure on the longer spanner.

A screwdriver does the same thing. For allen bolt replacement of JIS bolts always use the allen key like a screwdriver for tightening up - never like a spanner.

[allojohn]

The trouble is that a torque wrench is only as good as it's been manufactured, tested and looked after. If none of that is spot on they are useless or worse than useless. And the lower the force needed the worse they are.

Spanner design works pretty well to help with roughly setting the right torque for a bolt - an 8mm spanner is maybe 10cm long whereas a 20mm spanner is about a foot long (rough estimates - I have never measured them). More leverage for the same pressure on the longer spanner.

A screwdriver does the same thing. For allen bolt replacement of JIS bolts always use the allen key like a screwdriver for tightening up - never like a spanner.

Again I guess us dummies would expect the torque wrench to be accurate. But when you consider it may be from China all bets are off.
Good logic on the spanners & screwdrivers - hadn't thought of that.

[blowerbike]

80-90 inch pounds.
these bolts are made to break.
an inch pound tork wrench is your friend.

if you was close to me...i have a large coffee can full of these.