Cradle threads stripped

[slippery99]

Made a big mistake trying to clean junk off of my case threads for the cradle bolts and used a 1.5 pitch instead of the 1.25 pitch tap. Realized after 1 and a half holes that I was making the mistake, was overly tired and not paying attention.

So now I have, on the starter side of the motor, 2 good sets of threads/bolts/holes that will torque no problem on both ends of the motor and 2 bolts in the middle that won't torque and are nearly completely stripped.

Anyone have experience with this? Should I go one size up and cut new threads? put a longer bolt and use a nut to torque? Not sure how important the cradle bolts are vs. the case bolts - everything else on the lower case cover is in perfect condition.

thanks.
Jeff

 

[restosud]

helicoil is your friend.

 

[slippery99]

Awesome, thanks

 

[mikidymac]

You can also get longer helicoils than just the standard ones in the kits. The ones in the kits are probably too short to get enough threads in the cases. They are pretty cheap from McMaster Carr. I would probably get the 18-20mm long ones for the cases but measure the cases before ordering. You can always cut off a few coils if you buy them too long.

 

[Vortex]

Yep cut excess coils with diagonal cutting pliers.

 

[Pro-pulsion]

Or do the easiest method and find the SAE sized coarse pitch bolts that are the almost fitted cross over from metric...example, M6 is very nicely replaced with a 1/4-20 and will be much better for use in aluminum. I never understood why the OEMs always use fine pitch in aluminum. It strips far to easily due to lack of material between the threads. With the SAE that will just barely start in the hole, you can torque it in by hand with relative ease and it will cut its own threads not doing any damage to the casting or leaving metal chips to contend with. Plus no drilling required so no worries about drilling too deep. I have used this method numerous times with success on every attempt. It's not a method for those that want to maintain OEM hardware exclusively throughout but it will hold together far better than fine pitch threads and saves a critical hole from being destroyed due to mistakes with a drill or broken taps from a chip binding. I used this bolt cutting thread method to seal the crank on my old 650sx when eliminating the case drain system. Never failed or leaked. Just send the bolts straight into the drain holes with some JB weld as a thread sealant, worked flawlessly

 

[slippery99]

Yeah, I thought about finding the SAE and cutting threads to one size bigger. I think I'm going to try the heli-coil on the first shorter bolt hole and see how it goes - I've got two bad ones so may switch on the second - would like to retain the metric bolt sizes if I can. Have a couple piles of stainless metric bolts laying around.

 

[restosud]

Or do the easiest method and find the SAE sized coarse pitch bolts that are the almost fitted cross over from metric...example, M6 is very nicely replaced with a 1/4-20 and will be much better for use in aluminum. I never understood why the OEMs always use fine pitch in aluminum. It strips far to easily due to lack of material between the threads. With the SAE that will just barely start in the hole, you can torque it in by hand with relative ease and it will cut its own threads not doing any damage to the casting or leaving metal chips to contend with. Plus no drilling required so no worries about drilling too deep. I have used this method numerous times with success on every attempt. It's not a method for those that want to maintain OEM hardware exclusively throughout but it will hold together far better than fine pitch threads and saves a critical hole from being destroyed due to mistakes with a drill or broken taps from a chip binding. I used this bolt cutting thread method to seal the crank on my old 650sx when eliminating the case drain system. Never failed or leaked. Just send the bolts straight into the drain holes with some JB weld as a thread sealant, worked flawlessly

remind me not to buy used parts from you ...

 

[Pro-pulsion]

lol...I know better than to sell things that are set up that way. This is my fix for things that I don't intend to sell with the only exception of the 650sx which sold several years ago and is still running today. If I sell a part that needed modifying/machining, I make sure it is done well