Oil filter cover threads stripped casing XT recommandation!
 

Have a recommendation for everyone! Before threads go you wanna buy to bolts 6mm 90mm, cut off 3 threads and use it instead of original. They almost had room for 90mm but desided to just do 80mm long and you hold on to 1cm that wear out in time. Measure inside and you get excact mm, its not threads all the way in.
I read miss info here about dont do longer bolts its oil supply, no its not! The only bolt that have oil passage is lower and if you want block it its just for oil from filter draining when undo bolt. Infact you dont want oil from filter back into engine it can possible have material from engine there.
Remove top bolts, then open lower bolt a little så cover can be dropped down, clean out filter house, change filter. If you strip lower bolt you cant do longer, fill up with JB tap out again or do a insert thread then its still open as from fabric. Torque 10nm, new seal is good to have for correct pressure when torque up. I did the measuring on the XT 600 3TB and early 4PT same a little less than 2cm in. Measure others early models and its most likely same lenght in hole.

Nice tip! But which exact models?

Added info forgot its not only XT.

indeed, important info.
remember back then, when i've got my '02 xt, it already had leaky oil filter cover because of one or more weakened threads.
and that method with longer bolts gave me at least 3 more (active) years of oil-tightness there, until had to re-cut 7mm threads there..

It makes a huge difference if you got 16mm threads vs 10mm original holding bolt, bet you never wear them out, i have the 93 engine that have good threads still but never overthighten them, better go for 9nm than 10 if its not leaking. I found a kit with insert threads drill 6,3 and you can use original bolts all of the 6mm around the engine. Good to have in hand when doing some repairs, same as helicoil.

I have a few XT's and TT's. Replaced all the top filter cover bolts with 5mm longer 85mm length version available from Yamaha part number
91317-06085. Never a problem.

If you do need to helicoil the stripped threads then make sure to use the 12 or 15mm length version 6mm helicoil. The standard helicoil inserts that come in the kits is quite often only 6mm long. The thread is 18mm long in the case.

The problem with the 10nm torque figure that is recommended by Yamaha is that it is for totally dry threads, as are all of the other engine assembly torque figures. If you are torquing up threads that have oil on them, like the filter cap bolts usually have, then the torque figure needs to be reduced by around 25%

So basically if my 90 xt 600 is not leaking you suggest on cuttings 3 threads off on the bolts to prevent from stripping threads. Thanks

Buy new bolts, they are already old and weak on threads. 91317-06085

Thank you on this, also should I cut some threads off on these before installing

No they are correct length.