Yamaha TRX850 Enthusiasts Forum

My TRX developed an oil leak this Saturday. Noticed when I stopped for fuel on M5 services. Oil dripping on to exhaust in the filter area. Checked oil level which was fine so rode home with one eye on the warning lights. Just had a closer look tonight as I want everything spot on for my trip to Germany next month & it would seem that I stripped the thread for 1 of the bolts that hold the filter housing on when I changed my oil a few months back. I dropped the sump off for a better look & found a few bits of metal in that too. The hole with damaged thread is in the block, 20mm deep. hole for said bolt in sump is also 20mm deep & filter housing hole is 8mm deep making 48mm total but the longest bolt I've found is only 38mm ??? This would suggest that only half of the threaded hole was filled with bolt to me. Batteries on my torch went flat & it's getting late so I knocked it on the head for tonight but I've got to hope that either there is enough good thread left for a 10mm longer bolt to grab on to or if not, that I can drill & tap or helicoil the fecker but they are such small holes I don't hold much faith in either method working well enough. Why couldn't it have been the hole that goes through & out the other side of the housing, I could just put a nut behind it then.

Fed up now, my own fault I know but I've spent a lot of money getting the bike just how I wanted & now it starts "needing" stuff I hadn't allowed for. new battery last week, oil leak this week which could stretch into next week or month even before it's sorted. AAAAAAAAAAAAAAAAAAAAAWWWWWWWWWWWWWWWWWWWWWWWWW NUTS.
Can anyone suggest a quick fix I can try ?

Hmmm...... frustrating situation. Have you got the hammer out of the wall yet. Thta's where my would have ended up.

Can you drill the hole out bigger, thread that hole, fill with JB Weld , drill new hole for the correct thread size and cut new thread. Then use full length bolt. The bigger threaded hole is for the JB Weld to grip the parent material on. Helicoil would seem easier though, just do the 5mm of the hole and use a full length bolt........... or............ drill all the way through the housing and use the nut idea.......... just thinking out loud here.

Poor bugger, hang in there. If you use a Helicoil, have the bolt length stop at the end of it. You haven't got a hope in hell, of the existing thread matching the pitch of the Helicoil, and you could end up in a spot of bother if you try to use a long bolt to pick up on the good thread left in the casing, ( after you exit the H/coil ). Is that as clear as mud? I am pretty sure that there is a 'long' series in the smaller metric Helicoils

Thanks chaps, mate is an engineer (read know all) so will get him round tonight for his "expert" opinion. I've got JB weld & some stuff called quick steel & if I thought either would work, the hole would be full of the stuff right now.

Ah, I know the feeling, I hate it when it happens.
I would stick with the helicoil. It's a dirty job but once they 're in, it's even tougher then original.

Agree with above, plastic/molten metal can come out, helicoil do small sizes as well.

Dave E

Yep helicoil,each and every time.
Most are sprung steel,much tougher than the parent aluminium,you can even get stainless ones!
Alternatively if during a rebuild,fully weld up the hole,re-machine and tap,a rather more `involved` job though.

I've helicoiled bolt holes on a car gearbox before so it's not beyond me, just didn't realise they did a set small enough for what I need now. Thanks again fellas, feeling a bit better about it now. Might do the lot while I'm at it given that I'm obviously a bit heavy handed.

Did exactly the same thing with one of mine. I used a longer bolt, and am very careful how tight i go with it now. Been like this for 4 years and numerous oil changes and its been fine.

Funny you should say that Andre, I measured the depth of offending hole & there is a good 6mm that doesn't get tapped from factory (taps must have a fairly long point ?) so I tapped it out tonight & I'm off to get a longer bolt tomorrow.
With the sump off & the front of my bike hoisted right up in the air for easy access I also noticed a huge piece of swarf in the pick up gauze ! I expected a few bits of silver but this was shocking.
I now need sump gasket & left hand engine casing gasket (took it off to paint it). Are they available individually ?