Stripped primary clutch cover bolts

[SudburyApex]

Hi all,

I was replacing the primary clutch spring on my 08 apex with a new soft engage spring. When I went to reinstall the clutch cover (6 bolts) I snugged them up (I thought gently) with a 3/8 cordless impact. then I went to torque them with a 3/8 torque wrench set to 10ft/lb. Well, the bolts did not tighten... all 6 of them. Sooo, What are my options now? do I need to buy a new clutch? tap new threads? loctite?

thanks!

 

[SudburyApex]

Upon closer inspection of my torque wrench, it was actually set to 25 ft/lb. Dialing it back to the 10 ft/lb does allow it to click when tightening these bolts, but I'm thinking those threads are stripped and could probably use some help. Perhaps an application of loctite blue might work? Also I snapped one of the bolts during this process . Should I replace the whole set or try to track down a just the broken one.

 

[steiner]

If you truly stripped each one by overtightening them you will need to drill and tap new and larger threads.

 

[NOS-PRO]

Hi Sudbury, I work with clutches day in and day out and my best solution for you would be to replace the moveable sheave that the bolts go into. The Yamaha dealer close to you will be able to do that.

If the threads are not there to hold the bolt, Loctite won't help.

The primary clutch is the most critical part of the sled and at times is the most neglected. It spins at 9,000 + rpm and when it explodes....it is not pretty.

 

[SudburyApex]

If you truly stripped each one by overtightening them you will need to drill and tap new and larger threads.

Thanks for the reply. Yes I wonder about how stripped these threads actually are. When I was over tightening the bolts, they continued to turn without any increase (or decrease) in resistance. That's when I felt like something was wrong. Its very strange to me that I am able to snug up the bolts now and get the torque wrench to click on 10 ft/lb. Maybe the threads are somewhat intact to provide that minimal amount (10ft/lb) of tightness.

 

[SudburyApex]

Hi Sudbury, I work with clutches day in and day out and my best solution for you would be to replace the moveable sheave that the bolts go into. The Yamaha dealer close to you will be able to do that.

If the threads are not there to hold the bolt, Loctite won't help.

The primary clutch is the most critical part of the sled and at times is the most neglected. It spins at 9,000 + rpm and when it explodes....it is not pretty.

Thanks for the reply. I was afraid someone would mention something like this. You really want to know that this thing isnt going to blow apart while spinning at that speed :/

 

[Winderallday!]

Aluminum is less than ideal for thread strength compared to steel. If the threads are compromised at all, I wouldn't trust them. This is a situation where I use only hand tools vs impact wrenches as you don't really know how much torque you are using. The other thing is the RPM the impact wrench spins the bolt, the friction/heat generated can make the aluminum gummy and load up on the threads of the bolt destroying threads. To be 100% safe, I would do what NOS-PRO suggests and get a new sheave or find a low mileage used one.