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What caused this crack in my case?


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Guest utleybanshee
Posted

cracked my case about a month ago... just starting to investigate.. what do you guys think happened?? Any input would be greatly appreciated..

 

 

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Posted

I would say it was started by a chain break and the crack grew. Or the roughness of the metal allowed stress to build up and form a crack. That is why all your conecting rods in drag engines are pollished smooth. There is no rough castings for a stress riser to occure and lead to a failuer.

 

Do you have all of your motor mounts tight, including the bottom ones?

 

josh

Posted

this might be wrong but have you been hitting jumps latly? if so maybe ur chain was alittle tight when hitting the jumps and coming down and pulling on the sprocket which will put pressure on ur case?maybe idk just a guess cuz my buddy did that exact same thing on a blaster

Posted

I agree it was the chain. When you put that thing back together make sure you get a case saver on it before that happens again

Guest utleybanshee
Posted
I agree it was the chain. When you put that thing back together make sure you get a case saver on it before that happens again

 

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its a drag bike has never seen a jump... and front sprocket is an 18 to big for a case savor... but i was thinking the chain was too tight.. it happened after a launch.. i launched in a lil bit of sand then spin spin spin.. grip and i heard the crack.. so i was guessing the chain was too tight..

Posted

[its a drag bike has never seen a jump... and front sprocket is an 18 to big for a case savor... but i was thinking the chain was too tight.. it happened after a launch.. i launched in a lil bit of sand then spin spin spin.. grip and i heard the crack.. so i was guessing the chain was too tight..

 

That is a nice looking bike! If you launched in some sand and then hooked really hard it would not have made a differance how tight your cahin was i dont think. If you hooked that hard then i am sure thats what did it but it does look like the case was already week from a chain break.

Posted

the output shaft twisted because the chain was too tight. you might want to look into a bearing support, and leave a little slack in the chain. after you install new cases.

Guest utleybanshee
Posted
also.. probably should consider some straight cuts in 2.68 ratio or less so you can use the smaller sprockets and a case saver...

 

ok then i never thought of that.. thanks..

Posted

The whole area has a big piece missing from previous damage. Unless some one cut it out for the heck of it. Its pretty obvious a 4" piece is gone. Did you buy it this way or did you modify the cases?

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