Keep Calm and Crank on? Stripped crank

Hey yall.

Been moving along on my build. I bought this crank here.Budget Crank

Got the whole motor put together with CDI etc. I tried using this nut and it didn't work.

Moby Reverse Nut

I was told the crank thread was right hand so bought this nutty .

When I had used the reverse i lightly buggered up the threads. Just by trying to put it on my hand. Then I tried to thread on the new proper nut and decided to start 1-2 threads and clean them up by cranking the nut on with a wrench...

I KNOW. This isn't my first nut. Anyways, it messed up the new nut and threads. I bought a thread file, fixed the thread and today I was able to hand thread the nut onto the threads maybe 1-4 threads. Then it got tight and I decided to use my little impact to get it on. I figure it would "clean up" the nut.

WRONG. It was a gamble I know but it got jammed and DESTROYED my crank shaft. I've stepped off the edge of the bridge, and am now debating if I order a new nut and use what thread is left. Will I have enough thread???

I've dealt with thousands of nuts and bolts. The damn work frustration pushed me to force this and was the wronggggg nut to mess with.

IMG_0842.jpg

Re: Keep Calm and Crank on? Stripped crank

I'm a gambling man also. I'd cut off the messed up tip, make sure the threads are nice and clean, add a little oil to the crank and put a new nut on it.

Re: Keep Calm and Crank on? Stripped crank

Brandon Weiss (Detective brandon to you) /

Nut up and run it

Re: Keep Calm and Crank on? Stripped crank

Dirty30 Dillon /

Buy budget and get budget results I guess.

Re: Keep Calm and Crank on? Stripped crank

> Dirty30 Dillon Wrote:

> -------------------------------------------------------

> Buy budget and get budget results I guess.

Sounds more like miscalculation than budget , to me .

Re: Keep Calm and Crank on? Stripped crank

Maybe try to cut new threads?

Re: Keep Calm and Crank on? Stripped crank

I'd fix the threads , get the right nut and run it .

Re: Keep Calm and Crank on? Stripped crank

Probably Fred /

> Stephen Simmons Wrote:

> -------------------------------------------------------

> I'm a gambling man also. I'd cut off the messed up tip, make sure the

> threads are nice and clean, add a little oil to the crank and put a new

> nut on it.

You got it right

Cut the bad tip/end off and make it nice

Re: Keep Calm and Crank on? Stripped crank

Would using a tap and die work here? I did something similar when I used a metal hammer to hit the crank to split the cases (after heating them up). Threads are bent inwards and I don't want to buy a new crank and take the whole this apart.

For the OP - either buy a new crank or cut off the part of the crank with the bad threads and clean it up. You should be using this nut on the magneto side, https://www.treatland.tv/mbk-flywheel-reverse-flywheel-nut-11mmx-1mm-p/mbk-flywheel-reverse-nut-11x1.htm.

Re: Keep Calm and Crank on? Stripped crank

French Moby /

Yes, it was not a budget crank problem. It was an emotional and frustration problem lol. Next time I'll punt a cabbage or something, not work on my moped instead.

The thread is beyond repair, that's for sure. I will clean it so that it doesn't interfere with the new nut I'll be ordering.

Thanks y'all. This is like my free counseling when moped pisses me off.

Re: Keep Calm and Crank on? Stripped crank

looks fine, use a metal file to taper n a new nut.

Re: Keep Calm and Crank on? Stripped crank

Yeah, and keep the impact gun away from yer moped. Less chance of a booboo.

Re: Keep Calm and Crank on? Stripped crank

I've got an engine with a flywheel that's been held on by maybe one thread, crank snout is broken, for the last three or four years.

I had to replace the points over the winter and thought that was it, I'd have to finally replace the crank but I got the flywheel back on solidly.

Lots of thread locker on that nut.

Re: Keep Calm and Crank on? Stripped crank

Get a thread file and straight the lead in to the remaining threads, put a new nut on, fortunately it is a taper shaft so the flywheel does not need a lot of torque to grip.

If you feel it still is not trustable then drill and tap the snout of the crank for a M6 bolt and throw in a goodly machine screw as a safety lock.

Re: Keep Calm and Crank on? Stripped crank

♣Slew Foot♣ /

You get a tool called a thread chaser and it clamps on and it's like a nut basically you could take a die and cut it and then put it back together with a set of screws and then work it off with a huge wrench and a breaker bar

Re: Keep Calm and Crank on? Stripped crank

I've grinded down all the threads before and re-tapped/cut to the next thread size down on a spindle. You could do the same in this scenario.

Re: Keep Calm and Crank on? Stripped crank

French Moby /

Guys,

I lost motivation for the longest time. I ended up making sure I would have enough thread engagement. I cut off the tip of the crank, the damaged part. Then used a thread file. Went back on. More than enough thread engagement. No pics for now.

Going to start back up on this damn thing. (edited)

Re: Keep Calm and Crank on? Stripped crank

Richard Eberline /

I have a left hand die and a thread file.You can rent or buy. m10-1.00

Re: Keep Calm and Crank on? Stripped crank

> Francois Labat Wrote:

> -------------------------------------------------------

FIFY :

Keep Calm and Chive on . ;)

Re: Keep Calm and Crank on? Stripped crank

Totally normal JBOT /

This bad part can be cut off and and fixed....though you can drill the crank and tap a stud into it if needed. I did that with my buggered moby crank. Worked great. As long as there's tension against the taper that's all that matters (edited)

Want to post in this forum? We'd love to have you join the discussion, but first:

Login or Create Account