Oil Filter Drain bolt

Just back from the local yamaha dealers with my RHS engine case having had the oil filter drain bolt helicoiled:mad:. dont know if this has happened to anyone else but the mechanic there said its a common problem. bits of metal sitting under the oil filter fall into the hole in the bottom and end up in the thread of the bottom bolt which(suprise suprise) strip the hell out of the nice alloy thread in the case. its a pain to fix to as you have to run a very short helicoil into the end of the case from the inside. a help in this problem (and one being done by the dealer every 3rd oil change) is to replace the bolt as the threads flatten off after only having it out a few times. be careful of this when pulling that bolt out, it turns a simple oil and filter change into a long hard job. big congratulations to the guys at Coast Yamaha who did the helicoil in 15minutes while i waited and pinched the oil filter drain bolt off another bike so i could ride this weekend and all for $15 (aud)!!.


Lachy(who's enjoying at the moment cos its summer! YeeHa)

Yep, common problem, make sure you blow out the hole with compressed air every time you remove that bolt, it helps.

You might try turning the threads off of the bolt in the area that passes through the case only leaving the threads near the base of the bolt. That way as you remove the bolt, there are no threads that pull metal chips into the case threads. Why do you have to put the insert in from the inside?

Excellent advice. Thanks!

Reading this makes me wonder about magnetic drain plugs. Attracting all those little filings right where you wouldn't want them.

Are people finding damage occurs taking the bolt out, or putting it back in? I think I've read more about thread damage on reinstalling but you make an interesting point that the damage could have occurred on the way out. Hmmm???

Their actually talking about the bottom hex bolt for the oil filter cover, not the bottom drain bolt under the bike.

Dodger :D:)

Oops. show's ya what I don't know yet.

magnetic drain plugs are also not much use for bits of alloy. the reason i had the helicoil put in at the back is because of the oil gallery, wouldn't want to cover that little hole up. good idea about the shorter bolt that stops before reaching the oil gallery would be a much better solution(for anyone from Yamaha engineering department who might read stuff here haha!).

cheers for the responses.


I have always had such problems with yamahas and never with hondas. I always use torque wrench. I guess honda is using stronger material than yamis :)

Thanks for the advice. I'll make sure to clean up the threads the next time I do an oil filter change. The idea of cutting the bolts shorter is neat too.

Any idea how short it can be cut ?

I don't have a WR yet so I'm guessing. Put the bolt in, mark it with a grease pencil, take it out, place a nut over the threads to the base of the bolt, cut the bolt off at the mark (or just a tad shorter), or put on a lathe and turn the threads off leaving a taper on the threads, then remove the nut. The nut will form the threads back if you have damaged them during the process.

Again, I am guessing, because I have not seen one yet. Remember, it only takes one full thread to hold full strength, but count on having a 1/2 thread on the front for a leed thread of the bolt and 1/2 thread lead in the case. (not sure how short the bolt is yaknow), Leave at least two threads if in dought!, but you will probably have more than that to work with.

Hope this helps! Lets us know how this works if you do it? Again, why did you have to put the insert in from the inside?

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