Stripped bolt for oil filter plate

14 replies to this topic
  • yami426f

Posted September 05, 2001 - 04:01 AM


I stripped the threads on the lower allen bolt for the oil filter cover. What is the best way to fix it. Do I drill larger and tap it(ut what about te shoulder bolt that centers the bolt) or do I fill the hoe in with liquid steel and tap it the same size. I'm nervous about screwing somthing up..
Please help....

  • Nevada426

Posted September 05, 2001 - 04:10 AM


You might try a helicoil (is that how you spell it)set. I have one made by RECOIL that fits 6mm bolts and works great.

2000 YZ426F
2001 CR500R

  • yami426f

Posted September 05, 2001 - 04:38 AM


is a helicoil an insert? will I need to drill out the hole?

  • crazyadam

Posted September 05, 2001 - 05:29 AM


The heli-coil is a threaded insert made of stainless. the drill and insertion tool come in a kit, about 30$. drill size for a M6 x 1 would be 6.25mm or .2461" -- might be able to get away with a 1/4"
Emhart fastening tek or talk to Paul at ECKO tool (best prices, good guy) 800-524-9883
good luck!! dont worry, I use heli-coils every day (not in my bike, but at work) and the never fail

  • Glen_T

Posted September 05, 2001 - 05:58 AM


I striped the same bolt in my 426. It seems as though Yamaha did a poor job machining some of the side cases. I fixed mine after many hours of stress worrying about what to do with a heilicoil. You can get a kit at a local automotive store (they ain't cheap, $35 - $40 but the kit will have all the tools you need to insert the new threads). You'll have to take the side case off. Then just drill out the stripped part and insert the heilicoil as the directions instruct. It is a very easy job. One problem though, there is an oil galley that will hang up the heilicoil when you insert it. I used a pair of very long needle nose pliers to get it past that point. The repair is stronger than the original threads because they are now steel instead of aluminum. I suggest that you get a new bolt from Yamaha to avoid any problems you may encounter with the old threads. No problems over a year later! If you have any questions contact me at

  • Scooter426

Posted September 05, 2001 - 06:01 AM


If you are going to drill it out and tap it, why not just put in a larger bolt, and skip the helicoil? One less set of threads to worry about.

  • Glen_T

Posted September 05, 2001 - 06:10 AM


That's not a good option as the bolt is very sprecialized with oil galleys running around it. The best option is to fix the threads.

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  • Scott_F

Posted September 05, 2001 - 06:51 AM


This is becoming a common problem. I noticed it on one of my previous YZF's. Apparently what happens is when you change oil, metal debris runs down into those threads through a hole in the filter cavity. Over time the threads get buggered up.

Ty Davis recommends blocking that hole with a set screw to prevent the problem.

  • Maicoman

Posted September 05, 2001 - 11:58 AM


yami 426
sometimes if you did not strip out the thread to bad, you can simply re-thread the hole by re-tapping the thread. If the thread is completly wasted, then use the above advice.

  • Nevada426

Posted September 05, 2001 - 06:14 PM


I agree with Maicoman, if the threads are not to bad you can simply run a proper sized tap into the hole and clean them up. If the treads are too far gone the helicoil kit works great. I repaired two sets of threads on my fork tube with the helicoil set and now I can still use my factory fasteners and torque them to spec no problem.

2000 YZ426F
2001 CR500R

  • Glen_T

Posted September 06, 2001 - 05:19 AM


I did clean up the threads once, but it only lasted untill the next time I took the cover off. In my case it just put off the inevitable.


  • yami426f

Posted September 07, 2001 - 04:01 AM


I am going to get the helicoil set what lenght do i need. What do i tell the helicoil sales man i need. I need to get this done today.. I have 3 new bolts( incasei scew one up) coming in i hope today. I love how it take 2 weeks to order a $.99 bolt or a $30 fed ex
1. what do i tell the helicoil guy?
2. where online could i buy these bolts in the future.. it hink it is a special shoulder bolt( the shoulder is lager than the threads
Thanks for getting me back on my bike guys!

  • forloop

Posted September 07, 2001 - 05:41 AM



I got all my helicoil stuff at Pepboys or some autoparts place. Give them a try first.

01 YZ426F #85 Vet C

  • Glen_T

Posted September 07, 2001 - 05:53 AM


I got my kit at NAPA automotive. Just take one of your bolts in to match the threads. In the kit you should get several heilicoil threads, an insertion tool, a tap, and if my memory serves me right, you also get the proper size drill bit for the new tap. I would recommend drilling the hole on a drill press when you get to that point. It's not a tough job.


  • yami426f

Posted September 07, 2001 - 05:56 AM


thanks guys, hopefully my fearless yamaha dealer will have my bolts in... and then i'll giv it hell!!

Thanks again!

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