Stupid Me !

klaborde · Post by **klaborde** » Fri May 27, 2011 1:39 am

I did a very dumb thing tonight, and need some guidance on what to do.

I have a Buddy 125, and was very interested in changing the Transmission to an upgraded one. So I ordered the DR Pulley Clutch, and Dr Pulley Variator. I have been sort of hooked on Youtube lately, and I seen some Video's on the topic, and I said... Heck this looks easy for me to do, and I ordered the parts.

My neighbor offered to assist with this project, and he came over with his compressor and impact wrench to remove the Variator and Clutch for me, since I only had the basic tools to get the Transmission cover off.

Well, he stripped the bolt where the Variator is attached.
He says it was already stripped, and since he lives next door, I didn't want to make a big deal out of it.

Someone tell me the bad news, this looks like a major repair to me.
What should I do?

Hwarang · Post by **Hwarang** » Fri May 27, 2011 1:42 am

Take it to a dealer and pay them to make it all better.

Silver Streak · Post by **Silver Streak** » Fri May 27, 2011 1:45 am

Do you mean he stripped the threads off the end of the crankshaft?! Or just the threads on the nut?

If it is the latter, it is no big deal. If it is the former, it is a major deal! If he actually stripped the threads off the crankshaft, I believe there is no recourse other than to pull the engine, split the crankcase, and replace the crankshaft... or find another engine somewhere.

I'd be surprised if he was able to strip the shaft instead of the nut. I believe the crankshaft is hardened steel, and the nut only mild steel.

Beware well-meaning neighbors with impact wrenches...

Good luck.

klaborde · Post by **klaborde** » Fri May 27, 2011 1:48 am

We look at it pretty close, and it is the Shaft...
That is why he thinks it was already that way.
I purchased it used, and it had 5K miles on it.

Silver Streak · Post by **Silver Streak** » Fri May 27, 2011 1:50 am

Is there any possibility that what you are seeing on the end of the shaft is actually the threads filled with stripped-out debris from the nut? That could make it look like the threads on the shaft are stripped when they actually aren't.

klaborde · Post by **klaborde** » Fri May 27, 2011 1:57 am

I just took another look at it...
I still have the cover off.

No threads until close to where the washer would be near the Variator...
I guess I am "Screwed"...

Like someone said earlier, I just need to find someone in the Atlanta Area that will come pick it up, and I pay to make it better.

bigbropgo · Post by **bigbropgo** » Fri May 27, 2011 2:23 am

that blows me away that the crank threads would go before the nut threads. sux bigtime. if everything was stripped and damaged already, how was it staying together? (salt in the wound i know)

klaborde · Post by **klaborde** » Fri May 27, 2011 2:42 am

Well we watched a Youtube video by MRP...
They did the whole thing in like 30 minute, so we both were confident.

I had the transmission cover off already.
He has a 50cc scooter and we were going to take a ride tonight after it was done.

He put the gun on the Variator and I didn't think anything of it, and it did not come off at first. Then he tried again, and it came off.
When we put the Variator on, he put the nut back on had tight, and then he put the gun on it, and it was all over.

I post a message on the local scooter club discussion group, so hopefully someone with the same experience will suggest who I should call in the morning to get it picked up.

Gosh when I think the motor has to be rebuilt, that may not be something the local shops do. They all do the easy stuff, but this looks like a major project to me.

I just happen to find another post by someone else who did the same thing to his scooter, not local to me, but I wrote him a PM to see if he has any advice.

Thanks for all who replied tonight...

Dooglas · Post by **Dooglas** » Fri May 27, 2011 3:06 am

klaborde wrote:Well we watched a Youtube video by MRP...
They did the whole thing in like 30 minute, so we both were confident.

Beware of overconfidence! I know, too late. (Ah, in the future beware of neighbors with impact wtenches set at high torque levels)

Howardr · Post by **Howardr** » Fri May 27, 2011 5:34 am

I had a similar experience and replacing the crank will set you back $500 or so. That's when I decided to upgrade to my 183cc monster! Mwahaha!

Howard

CWO4GUNNER · Post by **CWO4GUNNER** » Fri May 27, 2011 9:47 am

Im not quite sure what it looks like as it been awhile since I changed the rollers on my sold Vino 125. So if there is a protruding shaft with threads that have been stripped off but the shaft is still there not cracked or broken off, all you do in re-thread it with a die of the closest next size smaller thread metric or standard whatever is closest. even if the shaft is a little uneven as long as it gets new threads from a tool that cuts new threads over the old using cutting oil, it will work. How do you think they solve these problems in 3rd world countries where there are no dealers to convince them they need a new engine.

As long as the support member has not been compromised i.e. the bolt stud has not sheered off, or the hole has not been damaged (cracked/filled), any threaded hole can be re-threaded with a tapped, and any bolt stud can be re-threaded with a die of the next smaller size "thread".
http://www.ehow.com/about_5063176_tap-die-set-used.html

A die is essentially a hard threaded nut with cutting edges. A die can make a bolt out of a plain steel shaft.

klaborde · Post by **klaborde** » Fri May 27, 2011 10:11 am

This is a wonderful idea !
I don't have a picture but it would be similar to what you have here where the first 1/2 inch has no threads, and then as it gets closer to the ribbed area they are are few.

I wonder if anyone has tried this and they were successful?

Thanks for the suggestion.
I am going to get on the phone this morning and see if the shops that do service on Scooters would do this. This looks like a lot less work then tearing the engine down to put in a new crank.

Keith

Lotrat · Post by **Lotrat** » Fri May 27, 2011 11:05 am

Sorry for your troubles. An impact gun should only be used to take things apart. A torque wrench is used to put things back together using recommended torque values. There is no way to use an impact gun to properly torque a fastener and should never be used in any kind of assembly.

jasondavis48108 · Post by **jasondavis48108** » Fri May 27, 2011 1:35 pm

Lotrat wrote:Sorry for your troubles. An impact gun should only be used to take things apart. A torque wrench is used to put things back together using recommended torque values. There is no way to use an impact gun to properly torque a fastener and should never be used in any kind of assembly.

+1 I've seen folks put things back together with impact guns and it always freaks me out

Raiderfn31 · Post by **Raiderfn31** » Fri May 27, 2011 2:11 pm

CWO4GUNNER wrote:Im not quite sure what it looks like as it been awhile since I changed the rollers on my sold Vino 125. So if there is a protruding shaft with threads that have been stripped off but the shaft is still there not cracked or broken off, all you do in re-thread it with a die of the closest next size smaller thread metric or standard whatever is closest. even if the shaft is a little uneven as long as it gets new threads from a tool that cuts new threads over the old using cutting oil, it will work. How do you think they solve these problems in 3rd world countries where there are no dealers to convince them they need a new engine.

As long as the support member has not been compromised i.e. the bolt stud has not sheered off, or the hole has not been damaged (cracked/filled), any threaded hole can be re-threaded with a tapped, and any bolt stud can be re-threaded with a die of the next smaller size "thread".
http://www.ehow.com/about_5063176_tap-die-set-used.html

A die is essentially a hard threaded nut with cutting edges. A die can make a bolt out of a plain steel shaft.

Booooooooooyaaaaaaaaaa!!!!!! Problem solved. Great post.

klaborde · Post by **klaborde** » Fri May 27, 2011 2:32 pm

Made contact with my local Buddy Dealer who has done work for me before. We talked about re-threading, but when I left it up to him he was against it... I would have to go find someone else to do this for me.

I am going to pay him a visit at lunch today and pre-pay him for the parts necessary to replace the cam-shaft, and get them Fed-X to him. Next week when the parts arrive, he will pick up my scooter and do the repair.

I get the impression from talking to numerous Genuine Dealers in the Atlanta area, this happens a lot, and more so on the Chinese Scooters...

Gosh when I get this thing fixed, I am staying off of Youtube, and I am going to ride and enjoy it, and stop changing it !

PeteH · Post by **PeteH** » Fri May 27, 2011 2:37 pm

Yeah, I don't know the innards under the transmission case yet, but my concern would be any other parts in that variator chain that depend on the full diameter of that shaft. If it's _just_ the threads and nut on the end, yeah, maybe, but I'd think it through.

Silver Streak · Post by **Silver Streak** » Fri May 27, 2011 3:13 pm

Rethreading with a die might work, but the crankshaft is hardened steel. It may require special thread-cutting tools like a lathe.

If it is indeed completely stripped, I don't see any harm in trying.

CWO4GUNNER · Post by **CWO4GUNNER** » Fri May 27, 2011 3:27 pm

You need to take it to either an engine machine shop or machinist shop, not a dealer who is interested in major repairs not simple fixes. Call some machine shops and explain the problem without allot of history. They will have you bring it down to take a look and get it done. The dealer would probubly sell you a new engine and then have yours machined himself. I have tapped and die myself a dozen times learned in high school metal shop used to be common knowledge like using a can opener. There is a chart you need to use that tells you which next size die cutting nut you can buy and do this your self using a wrench and some motor oil. Start the right next size cutting die on the end turn- cut a 3/4 turn clockwise, then turn back 1/2 a turn counterclockwise to clear out the cut metal and clean the new threads (like a lawn mower), then add a drop of oil to the threads and continue clockwise cutting another 3/4 turn and then back counterclockwise again 1/2 turn to clean out the new cut threads. Repeat over and over until you have a new set of threads. Then remove the cutting tool clean off the new threaded shaft and replace with the correct size threaded bolt available at any machine bolt store. That's it about as difficult as cutting the front lawn.
http://www.youtube.com/watch?v=tmoIHJdyyZM

Silver Streak · Post by **Silver Streak** » Fri May 27, 2011 4:00 pm

I also have done it many times on mild steel, brass, and aluminum, but never on the hardened stuff crankshafts are made of. I suspect it's nowhere near as easy, and far harder than cutting the front lawn. The die is likely not much harder than the steel you are cutting the threads in.

I agree, though, about taking it to a machine shop rather than the dealer. They specialize in this sort of thing.

CWO4GUNNER · Post by **CWO4GUNNER** » Fri May 27, 2011 6:29 pm

If that were really the case then the bolt would have stripped and the shaft threads would have only been superficially damaged. But your right for most this procedure is not that easy but for me its a vary simple and strait froward procedure. Even if the shaft was as hard as tool and die steel, which of course its not, all one would have to do is heat sink the the rest of the shaft then anneal the surface of the threaded area before for softening and after re-threading for re-hardening.

You know in life there are no real problems, only solutions.

BlueMark · Post by **BlueMark** » Fri May 27, 2011 11:05 pm

I don't see any reason not to try cutting new threads. If it works, that was cheap and easy. If not ... it did no harm to try.