Chains 410 vs 415 drive chain, catasrophic failure brand new engine

what i did was epoxy a strip of sheet metal in place.for the chain i happened to have an old garage door opener chain under my bench,same pitch and width.go figure.its a far better chain,feels heavier when cut to the same length.just going to check for burrs on the sprockets.
 
Chain jumping is caused by one thing and one thing only, a chain that's not tensioned properly. If your chain looks like this, it's not tensioned properly. You wouldn't keep the pedal-side this loose, what makes you think this side should be this loose? It's not the engine manufacturers fault your chain is jumping and it sure isn't the stores fault, it's yours.

loosechain01.JPG
 
Cavi mike

That may be true however I have not heard of any "Motor case explosions" with the 415 chain if so they are very few and far between.

So that being said, regardless of the alignment or tension the fact remains since they started sending out thinner chains more and more folks are having "Case explosions".

Just a prime example of someone trying to make a buck by shaving a little off the consumer is all. My buddy bought a GRUBEE 2011 Sky-Hawk GT5 66cc
Slant Head that had the inferior thin chain with it it ended up breaking in half & he was dead on as far as alignment & tension goes.

First one side of a link in the chain just fell off "not even the master link". So he tried to pedal the bike home and after maybe 75 yards it broke no tension on it either...well what little it takes to move the piston with the motor off and clutch pulled in & it still broke. I had a blast letting him have the "I told ya so" all the way home

At this point I just towed him home with my awesome bike w/the #415 chain.
For a tow strap we used several bungee cords and his broken chain I hardly knew he was there. Word to the wise let the guy in the rear of a tow situation do the braking !!! "Especially if he is a numb skull".

I guess the skinny chains aren't completely useless it made a semi decent tow strap !! At present that same chain is holding a Buoy to a thin cable that goes down to a Lobster pot in Cape Cod bay ..

My Buddie and I tack weld razor blades to our lobster pot ropes for the poachers that like to pull our pots & steal our food. More than one a bloody stained rubber glove has been attached to our ropes. We use to do it to ropes but they would get ****ed and cut the rope after they got cut So we switched over to chain & cable the razors tack weld nicely to the small chain.
One day we pulled up a pot & it had a 6 pack of Heineken Bottles in it .
Ice cold too ..:bowdown:
 
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i had just checked the adjustment.the reference jumpa made to the side plates letting go is exactly what happened.i epoxied a steel plate in there,if it piles up againit wil break epoxy,if i had welded it,most likely next chain failure would be the end of the motor.
the tell tale signs was a little bump i felt ,two or three times.
worked perfectly for 60 or so miles,not even a hiccup.alignment is good,so i blame cheap chain.
 
That may be true however I have not heard of any "Motor case explosions" with the 415 chain if so they are very few and far between.

So that being said, regardless of the alignment or tension the fact remains since they started sending out thinner chains more and more folks are having "Case explosions".

Just a prime example of someone trying to make a buck by shaving a little off the consumer is all. My buddy bought a GRUBEE 2011 Sky-Hawk GT5 66cc
Slant Head that had the inferior thin chain with it it ended up breaking in half & he was dead on as far as alignment & tension goes.

First one side of a link in the chain just fell off "not even the master link". So he tried to pedal the bike home and after maybe 75 yards it broke no tension on it either...well what little it takes to move the piston with the motor off and clutch pulled in & it still broke. I had a blast letting him have the "I told ya so" all the way home

At this point I just towed him home with my awesome bike w/the #415 chain.
For a tow strap we used several bungee cords and his broken chain I hardly knew he was there. Word to the wise let the guy in the rear of a tow situation do the braking !!! "Especially if he is a numb skull".

I guess the skinny chains aren't completely useless it made a semi decent tow strap !! At present that same chain is holding a Buoy to a thin cable that goes down to a Lobster pot in Cape Cod bay ..

My Buddie and I tack weld razor blades to our lobster pot ropes for the poachers that like to pull our pots & steal our food. More than one a bloody stained rubber glove has been attached to our ropes. We use to do it to ropes but they would get ****ed and cut the rope after they got cut So we switched over to chain & cable the razors tack weld nicely to the small chain.
One day we pulled up a pot & it had a 6 pack of Heineken Bottles in it .
Ice cold too ..:bowdown:
What? Skinny chains? Razors? Lobsters???? Were you **** drunk or stoned when you typed that?

You can blame whatever you want but the fact remains, a properly tensioned chain will not jump. Period. Obviously you've never noticed just how misaligned the gears are on a 21-speed bike when using the opposite outer-most gears. They don't derail because they are tensioned properly. Tension your chain properly and you won't have a derailment.

It is your fault, accept it, change your methods, and stop blaming everyone else.
 
ok.my sprockets were very close in alignment,engine is solid (welded bracket) in frame.
had just checked tension before ride as i always do.
less than three miles riding and poof! game over.two side plates let go,and compared to an old garage door opener drive chain,its an inferior chain.just in weight comparison alone,its noticeable.
i'm a licenced motor vehicle technician,my garage looks like a small machine shop.my mechanical ability is beyond question.
i can source enough chain to last me a lifetime,people throw away old garage doors openers every day.the repair links fit perfectly,chain is a perfect match.
 
There is a vendor that sells a gizmo that prevents engine damage if this occurs. I don't recall the website.

Almost everyone who has built more than several motorized bikes has had this happen to them once. I was not happy the first and only time this happened to me destroying a new engine on its maiden run.
 
I agree with him that the kit chains are junk! Especially the "wide" chain that has the same inner rollers that are meant for a skinny chain. Throw that junk away or repurpose it :unsure: and buy something else. I'm using a KMC Z-chain BMX chain, and it solved the problem right away. The small sprocket that drives the chain also contributes to the problem. That can't be changed, but using a garage door chain or similar industrial chain should be a major upgrade.



What? Skinny chains? Razors? Lobsters???? Were you **** drunk or stoned when you typed that?

You can blame whatever you want but the fact remains, a properly tensioned chain will not jump. Period. Obviously you've never noticed just how misaligned the gears are on a 21-speed bike when using the opposite outer-most gears. They don't derail because they are tensioned properly. Tension your chain properly and you won't have a derailment.

It is your fault, accept it, change your methods, and stop blaming everyone else.
 
putting on my pre - stretched garage door opener chain was a good decision.
60 or so miles and have not had to adjust yet.no hiccups or snags.
a couple drops of oil once in a while and we be rockin.
 
I agree with him that the kit chains are junk! Especially the "wide" chain that has the same inner rollers that are meant for a skinny chain. Throw that junk away or repurpose it :unsure: and buy something else. I'm using a KMC Z-chain BMX chain, and it solved the problem right away.

KMC Z-chains are junk. If you look closely at the end of the link, you'll notice the inner side-plates don't have a bushing pressed into them(like the kit chain does). Instead, the side plates are stamped into a bushing-like shape. Then the roller goes over that. These chains wear very quickly and can't withstand the heat generated from moving as quickly as the engine-side chain moves. They are bicycle chains for a reason, they're for bicycles.

Now, if you look at the chain supplied with the kit, you'll notice there is a separate bushing pressed into the side plates and the roller slides over that. THAT is a proper roller chain designed for use with engines.

Z-Chain(silver) JUNK.
Proper roller chain from the kit(black) GOOD.


zchain.JPG
 
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