Gs 1100 left end crank breakage

[Homie]

an impact is not going to push the rotor any farther that it is meant to go no matter how powerful it is.
your impact is also not going to break anything we are speaking of.
you throw the torque specs out the door on big stuff.

Fortunately I don't have a problem with mine ... yet. But if the time ever comes where I have to do something with it I'll just crank up the air pressure and "impact it's bag off"! But why "pray or sell it"? Is it kind of like once it's been off it never goes back on like it is suppose to? It then becomes a matter of time before it spins itself off and chewing everything up in the process?

[blowerbike]

Fortunately I don't have a problem with mine ... yet. But if the time ever comes where I have to do something with it I'll just crank up the air pressure and "impact it's bag off"! But why "pray or sell it"? Is it kind of like once it's been off it never goes back on like it is suppose to? It then becomes a matter of time before it spins itself off and chewing everything up in the process?

tom it appears to you 83's...
so this problem does not pertain to your equipment.

[Homie]

tom it appears to you 83's...
so this problem does not pertain to your equipment.

woo-hoo '83's!

[bonanzadave]

woo-hoo '83's!

Boo-hoo 82's

[Homie]

Dave, refresh my memory as to how you fixed that? Replace the crank? Weld repair? Or did you clean it up, reassembled and "impact it's bag off"?

[blowerbike]

not a fix but a band aid.
so what's up your a$$ homie?
just bored?

[bonanzadave]

Dave, refresh my memory as to how you fixed that? did you clean it up, reassembled and "impact it's bag off"?

Yes. I lapped the surfaces with coarse grit compound. Cleaned it with alcohol. Used permanent locktite. and BAGGED it !!! with a 1/2 impact. I believe it is.....forever.

[Homie]

Thanks Dave, hope it holds!

Terry ... WTF? Living up to your avatar saying I see.

[evh]

I'm having a hard time understanding what cause these crank failures.. Can somebody explain in detail? Is there not a keyway on that taper as well? I just haven't ever had one of these infront of me to see first hand..

[GregT]

The rotor assembly works loose over time. It starts moving on the taper - there's always just enough clearance over the key to allow this. Eventually there's enough movement that the assembly will act as a rotary impact hammer....Given a big enough rev and back off situation it will shock the end off the crank. QED.

The pic posted of the damaged end is the alternative scenario - the key has broken up before the shaft breaks. It's pretty clear that the asembly has been fretting on the taper. For what it's worth the key is not required - there's no need to index the rotor to anything and given a clean taper nothing should move.

[Kaiser Sosei]

There is no key.

[evh]

so it's just a tapered press fit with a nut.. no keyway.. Hmm.. so is this what usually happens or has anybody seen the crank break clean between the bearing and rotor?

[blowerbike]

THERE IS NO KEY WAY!


what does the damage is rolling RPM's high and snapping throttle closed or down shifting like a road racer.
at the track a person need to pull in the clutch at the same time he closes throttle at the end of the track.
just picture the several pounds of material on the very end of the crank spinning.
then abruptly stop or slow down the spinning mass.
that's a lot of force on a small area where all this weight spins.
83 and up 11--/1150 is larger and a lot stronger because of the size difference in the taper area.
(several mm larger).
i have never seen the later snap off...only the 80-82 silver engines(small taper).

let the above absorb into the brain cells

[bonanzadave]

I find myself engine braking more than I probably should. Coming off the freeway ramps Im always down shifting the revs up.

[GregT]

There is no key.

Correct of course - and I apologise for my misleading post. I was fooled by the pic - and a faulty memory. Been a while since i did an 1100 crank - nothing but 8V motors for the last couple of years.
Sorry.