stripped fork pinch bolt remedy

Started by VisceralReaction, June 08, 2011, 09:40:28 AM

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VisceralReaction

I blame it on the torque wrench.
So i was working on the bike the other day and putting it all back together and
the left fork pinch bolts were going father than they felt they should be going before the "click".
They hold just fine for now but I think I need to tear apart the front this weekend and replace
the bearings.

So. What would be the best remedy.
I've looked into time-serts and heli coils etc.
Or would the best option just to be to drill and tap and go with a larger bolt?
There are squirrels juggling knives in my head

Speeddog

Which pinch bolts, specifically?

What year and model of Monster?

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bikepilot

Pinch bolts don't take much torque and are fairly large bolts.  You'd probably have to torque them about 8x as much as is wise before anything broke.  I usually under-torque the lower pinch bolts just a bit as it is so easy to slightly deform the tube.  You'll see on some bikes when you rebuild the forks that the anodizing is rubbed off where the tube is pinched - this is partly due to the tube being squashed by the clamp. 12-14ft/lbs is plenty to keep everything where it belongs.

On high-hour bikes with lots of hard use I've seen the bolts fatigue and come apart. 

2009 XB12XT
2006 Monster 620 (wife's)
1997 TL1000S
1975 Kawasaki H1 Mach III
2001 CR250R (CO do-it-all bike)
2000 XR650R (dez racer)
2003 KX100 (wife's)
1994 DR250SE (wife's/my city commuter)

VisceralReaction

#3
^ yeah thanks for the lecture. I know it's 12lbs on the bolts. Like I said I blame the wrench.
and i was no where close to trying to turn those at 96lbs (8x)  :P
it's actually on my 05 ST3. It's the axle pinch bolts on the left fork.
There are squirrels juggling knives in my head

bikepilot

I've always thought fork pinch bolts are the ones to secure the fork (threaded into the triple).  I do axle pinch bolts to 8lbs max and yeah, people manage to strip those with some frequency. Its helpful to try and develop a feel for how tight something is so you aren't blindly relying on a torque wrench.  With a little practice you should be able to nail it with about a 10% margin :)

I bought a husqvarna once (which came with 43mm inverted showas back then) that had a stripped axle pinch bolt.  To fix it I pulled the cast lower bit off the fork, had it welded, drilled and re-tapped.  Worked great, but a lot of work.  I was in high-school and had plenty of time to wrench back then ;D
2009 XB12XT
2006 Monster 620 (wife's)
1997 TL1000S
1975 Kawasaki H1 Mach III
2001 CR250R (CO do-it-all bike)
2000 XR650R (dez racer)
2003 KX100 (wife's)
1994 DR250SE (wife's/my city commuter)

booger

If you used a Timesert you would then have steel threads as opposed to aluminum. Preferable in situations where the steel bolt will be removed and reinstalled over and over again. Timeserts are a good invention.
Everybody got a plan 'till they get punched in the mouth - Mike Tyson

2001 M900Sie - sold
2006 S2R1000 - sold
2008 HM1100S - sold
2004 998 FE - $old
2007 S4RT
2007 Vespa LX50 aka "Slowey"
2008 BMW R1200 GSA

VisceralReaction

I was thinking timeserts but haven't thought about how
you would drill and tap the rear of the pinch assembly only. I'm not familiar with the timeserts
enough to guess.
There are squirrels juggling knives in my head