Jump to content
Sign in to follow this  

Stripped tranny drain bolt

Recommended Posts

My 2004 CRF 450 has the case stripped out where the transmission drain bolt is installed. Does anyone know which size and type of tap to use to correct this? My bolt has stripped out and a new one won't go in so I need to fix the threads on the case. :banghead:

Share this post


Link to post
Share on other sites

I believe that is an 8mm x 1.25 pitch bolt...Try chasing the threads carfeully before going too crazy....Buy the aluminum washers from Honda that should have been replaced and only tighten with a 1/4" drive socket/ratchet. You should be able to buy that tap at a decent automotive supply or from Sears...Good luck to ya

Share this post


Link to post
Share on other sites

Go to an fastener supply outlet (even Lowe's or HD) and buy an exact same thread pitch bolt but 1cm longer. You may have enough threads left in the case to "torque" doen the drain/case bolt. Use a new 'crush' washer EVERYTIME. Next time you need to tear down the engine have the right case half threads repaired then.

Do not try to tap the case with the bike togehter. No matter how careful, nor how much grease you use metal filings will get into the trasmission. They will work there way into and contaminate the bearings and then you will have a much bigger problem. I stripped my threads like you, tapped it like you're thining and when I had the engine down for another problem caught the bearings before they failed,avoiding a HUGE disaster. I now replace the washers EVERYTIME and no problem.

Sorry for the longwinded reply, God Bless.

Share this post


Link to post
Share on other sites

My tranny drain bolt is also very close to stipping out. I have been extremely careful not to overtighten it, but I still have a problem. Sounds like a design problem to me. The threads on my drain bolt appear to be worn down. I will buy a new bolt first to see if that corrects the problem. The aluminum washer appears to be in great shape, but I will replace it also. I am not sure it that is the "crushable" washer referred to earlier.

Share this post


Link to post
Share on other sites

Had the exact same problem. Replaced the bolt with an allen head bolt very slightly longer and was able to get it to thread just fine. I think the problem is a poor quality bolt combined with a very close fit to the side case causing you to misalign the bolt. The allen bolt makes installation much more "straightforward".

Share this post


Link to post
Share on other sites

The allen bolt is a great idea!

Replace the "Crush" washer, just like tha manual says. I agree that you don't "have" to. But, the "crushing" of the washer helps reduce the chance of over torqueing and the terrible alternative of stripped case.

I just wish Honda would put an additional case bolt in and let the tranny and engine oil drain bolts be striclty "drain" bolts and not have to pull double duty! At least if you did strip them the repair would be so much EASIER!

Share this post


Link to post
Share on other sites

most of my bolts on my 03 crf450 were replaced with allen heads. Like the shroud bolts, and exhaust bolts.

Share this post


Link to post
Share on other sites

Why? Now you have to chisel out all the mud. I can only think of reasons why not to change to allens. Why are allens better than bolts?

Share this post


Link to post
Share on other sites
Why? Now you have to chisel out all the mud. I can only think of reasons why not to change to allens. Why are allens better than bolts?

i think the idea is that its not as easy to overtorque allen head bolts.

Share this post


Link to post
Share on other sites

Thanks for the ideas, but I really could care less about allen bolts as they are not going to fix my stripped out case. You'd need a socket extension just to reach the drain bolt. I'd like to know the exact p/n of the bolt that is longer and might help me without pulling the engine?

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Reply with:

Sign in to follow this  

×
×
  • Create New...