Too much power

[cory151]

After our 40 mile ride last Saturday, I really started to like the sound of the tuned pipe another cruiser had. So I ordered an anodized intake and tuned pipe and my ability to climb hills went up substantially.

One to many uphill blast with my 220 pound ass and my China girl spat out what I believe to be a crank key way of sorts. Anyway, i assume its easier to just replace the engine ( Im thinking something from Italy). May as well, because if your not doing 30-35mph you fall behind on these San Diego rides haha.

Heres the tooth she spit out....

 

[timboellner]

Did that come out of the exhaust pipe?
If it did I doubt it's a woodruff key.
That sucks.
It could be a chunk of piston ring.
Have you taken the head off to take a look see?
It may or may not be too serious.
Get adventurous and find out what you can.
Good luck and go get your hands dirty.
I think we can help you fix it if you want to
TiM

 

[wheelbender6]

Sorry to see that happen. These engines were probably designed to haul a 140 lbs guy and a couple of chickens.

 

[cory151]

Did that come out of the exhaust pipe?
If it did I doubt it's a woodruff key.
That sucks.
It could be a chunk of piston ring.
Have you taken the head off to take a look see?
It may or may not be too serious.
Get adventurous and find out what you can.
Good luck and go get your hands dirty.
I think we can help you fix it if you want to
TiM

I used to assemble crate engines for Summit Racing, it is definately a woodruff key. It came out of the clutch cover. I was surprised how soft of a material the key was made of. I may fix it, but I been looking for an excuse to get a Morini.

 

[corgi1]

Did the motor stop pulling ,or was it an extra key that was overlooked(not retrived) after being smuggled out of the country in the clutch cover for later retriveal?
any thing to save on shipping,lol

 

[earl.k]

its clearly a woodruff key... and i had mine come out of my small drive gear. when it did, it got wedged somehow. and snapped my gear into 3! so id check and see if yours is still in there, and go from there. hope it is a extra one

 

[Mac]

Not an uncommon issue. My son has a PK-80, I actually welded the keyway to the crank, (not recommended for the faint of heart), or recommended at all, but the key came out several times, figured I needed a new crank/motor, so I gave it a shot and then machined/sanded the weld back to a "Keyway" shape, still running today. I did find that some green loc-tight or superglue works well to ensure the keyway doesn't "rock" out of the way as the gear is installed on the shaft, helps if the clutch gear is removed so the small gear doesn't have to turn while being installed on the shaft.

Mac

 

[earl.k]

i tried the glue method on the motor i just put together for my friend. i used a rubbery but strong glue. i put the glue down, then the key. and installed the gear after. i dont know if it will help at all. but worst case is im out a dob of glue and it comes out again.

 

[cory151]

That is right where I found mine jammed between 2 teeth on that little gear. I'll bust out the old TIG and see if I can just weld it on with the motor still mounted. Thoughts?

 

[Mac]

cory151,
If you choose to weld it, be careful, heat will be real close to crank seal(wet rag??). I was at a dead end with my son's, had nothing to loose so to speak. The key just needs to NOT MOVE when the gear is installed, that's it. Good luck.

Mac

 

[cory151]

Mac, did you buy a new key or just reuse the old one?

 

[Mac]

In my case, didn't use any key, just built up material a bit at a time, used High speed die set up to grind back to shape. Again, I do not recommend this, It's touch and go at best, I got lucky. But if I had no other choice, I would use a new keyway, get a STD.(sae) one and grind it a bit to fit the metric slot, since it's most likely a bit of a mess in the keyway area anyway, just put a small Tac on the outer end to hold keyway firm and install the small gear. A final note:

NOT THE RECOMMENDED REPAIR FOR A DAMAGED KEYWAY

Check Six as they say in Aviation. Good luck.

Mac

 

[oldtimer54]

That is right where I found mine jammed between 2 teeth on that little gear. I'll bust out the old TIG and see if I can just weld it on with the motor still mounted. Thoughts?

You would be way better off gluing it into place then welding it. If I where going to try that (I wouldnt do it myself) I would use JB weld.

 

[Creative Engineering]

The first CAD graphic below shows what typically happens when installing the gear. The sharp edge of the keyway catches the key and rolls it out of the slot.

As can be seen in the second graphic...If the gear is installed correctly the key is trapped and can not escape.

The third graphic shows the fix. Simply deburr the edges of the key slot with a small file.

Swiss file sets are cheap...

12 Piece Needle File Set

Jim

 

[oldtimer54]

Great thanks this is just what I was looking for. This is what I would do.

 

[thatsdax]

The China Girl or Good time motors are low HP motors. Around 2 maybe 2.5 hp if you get lucky. Some factories place or install 2 base gaskets to lower compression and hopefully not affect port timing, which it does. Factories do this in order to exchange performance for longer life. And this works. If you soup these motors up, chances are very good they will beat themselves up in no time since they are not designed to handle any more than 2 hp or so. Keep in mind, the average man can make around 1.5hp on a bike. So having 2hp or so is fine. Just remember to consider that souping up a China Girl motor will "typically" only shorten its life. I can say that cleaning up the exchange ports and intake and exhaust ports and a tuned pipe would be the extent of any performance upgrades. But even this can severely shorten the life of one of these motors. There are many factories that make these engines and they all have pretty much figured out the casting and assembly hierarchy and assembly methods of providing a good life for their motor. Bottom line is.. These are not High Performance motors. What these motors do is provide a Ton of Fun.. Cheap fun and are great toys !! Soup them up at your own risk !! And .. Enjoy the ride...

 

[Mac]

Was hoping someone would help out here, Thanks Jim(CE), good graphic. I found a bent scribe, using it behind the keyway/gear, is helpful in keeping the keyway position while installing the gear also.

Mac

 

[cory151]

Thanks for all the help gang, what I may do is simply order an assortment of similar sized keys and use a die grinder to shape and chamfer the size and fitment I want. I wonder if a harder material key would cause issues down the road?

 

[lazieboy]

Here is what i am looking at. Is this the correct tool to remove small gear. if so do i need to remove to put the key back in.? What happens if u go without this part. 1st time doing this. Couldnt attatch pics how do i resize my jpeg to send?

 

[DaveC]

Red LockTite's full name is Stud and Bearing Lock. Get things real clean with carb or brake cleaner do the other prep stuff, too, put a drop in the slot. Set in the key and leave it for a bit. When the gear is installed the LockTite sets and nothing moves, then. Breakage or heat will be the only thing to get it apart