Jump to content

Recommended Posts

Posted

so went for a rip yesterday when my bike came to a loud stop. looked under the motor and seen the crank had destroyed my upper and lower bottom end cases. after taking the motor apart i seen there was alot of damage, the rod let go right under the wristpin and destroyed everything in its path. its a 4mil crank with a 421 drag ported head all bought from kevin. the bike only has about 3-4 tanks of fuel through it and im confused about what could make the rod let go like that. im going to upload some pics so i can get some input from you guys (cylinder repairable?, cause of failure, rebuild suggestions, ect.) my mods are below. im new to uploading so hopefully they work lol

  • Replies 157
  • Created
  • Last Reply

Top Posters In This Topic

Posted

Holy shitballs... My guess would be a seizure on that side, but could have been a casting flaw on the rod... What brand crank was it? I know you said it was from Kevin, but I didn't see a brand. If you say your plugs were a chocolate brown, that would indicate that you were not running lean.

Posted

Thats fuckin awesome!!!! Worst ive ever seen. I cant really tell cuz my eyes are goin but is that molten alluminum on the right side in the bottom of the case??

Posted

You Might as well take the trans and other parts out of those cases and start from scratch. That cylinder might be salvaged but those cases and crank are junk. Thats the worst rod slingin ive seen yet!!!!!

Posted (edited)

that's what always happens with them cheapo taiwan rods. i would talk to kevin. when i bought my crank from him, he told me he would replace whatever got damaged from the crank breaking, as he was that confident in the crank he sold me. i would call kevin. he seems like a pretty straight shooter.

 

its my beleif that the taiwan rods can't take the extra mass of the 68mm pistons and at higher rpm the rod stretches too much for the taiwan steel and snap.

Edited by mopar1rules
Posted (edited)

All to save a few $. "Should of got a wiseco"

I would be furious. How many hours on the motor?

 

Sent from my iPhone using Tapatalk

Edited by zach45
Posted (edited)

i had 5 of those cranks with 29 l/r on the rod either break or bent in a two month period

NONE of them had more than 5passes on them

 

 

 

 

all came from the same place

Edited by stroking

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...

×
×
  • Create New...