Crankcase Bolts Stripped?

[Yeaw]

So I was down cleaning my crankcase a week or so ago and I noticed two of the bolts were hand loose. It seems that a previous owner of my bike had stripped these two bolts. I had been noticing grease buildup on that side fairing, so this small oil leak was causing this. The end of one of the bolts was pretty messed up, so I ordered a new one, hoping that the bolts would have enough thread to grab on to, to at least tighten them a little bit. No go. So a little bit of oil is leaking from this area, mostly looks like through the bolt hole on the left hand side one. The bolts are in, but they won't tighten. Is there anything I can do about this? Or should I just leave it alone? The two bolts are marked in red.

 

[assnelbo]

If the crankcase itslef is stripped, you can helicoil it. If you have never used a helicoil before, you might practice on something more expendable then a crankcase, or have a friend lend a hand. The procedure is basically as follows:

If you do not own a tap and die set, you may purchase just the size you need form Kragen or another auto store. You drill out the hole (the package will tell you what size drill bit to use) VERY CAREFULLY AND LEVEL. Then, you use the tool, and slowly work the tap VERY LEVEL into the hole. Keep lubing it (6 in 1 works good) as you go, and every 1/3 -1 turn or so, back it out to get rid of the shavings. Keep doing this until you are almost all the way through the metal (the intructions will give you more specifics). Then you load this spring-looking thing into the threads that you have made, and wala, you now have a new, unstripped set of threads.

As long as the metal is thicker than the coil, it's not that big of a deal. However, if you have to start cutting the coils and such, it can become a real PITA fast.

The most improtant thing is to go slow and keep it straight!

Good luck!

Oh, and in the event that the hole is not entirely stripped (i.e. the thread are worn a little thin, but they aren't totally bent, warped, sanded down to nothing, etc, you might even get away with throwing some silicone on there to stop the leak (be sure to get the high-temp stuff) and maybe some loc-tite on the bolts themselves...

First thing I would try would be new bolts, though. Then the silicone/loc-tite, and then the helicoil. So, basically, read this post fromt he bottom up.

Good luck!

 

[Yeaw]

Already have new bolts, so that didn't help. As far as the silicone goes did you mean on the bolts themselves, or just around the crankcase gasket itself?

To helicoil it I would need to remove the crankcase cover right? I'm assuming the threads are in the crankcase to hold the cover on, correct? Even when backing it out to remove the shavings, aren't you going to get a bunch of shavings in the crankcase?

Thanks for your help, sorry if my questions sound silly

 

[assnelbo]

Yes, you will need to remove the cover to use the helicoils. As for the silicone, I would put it around the hole, so that when the bolt is in place, it seals around it and stops the leak. However, I doubt that will suffice if you have no grip from the bolts - hence the loc-tite on the bolt to thicken it up and help hold it in place. Frankly, I don't think it will work, unless the threads are barely stripped, but it is cheap and easy to try...

Indeed, you may still end up with some shavings in the crankcase, if the holes have open ends inside the cankcase. Maybe you can get something in there to catch them? Perhaps some tape over the opening, if you can get to it? If the backs are closed, spraying the lube and backing it out will get most of the shavings out the front. Any time you helicoil anything, you should back it out every so often because the shavings can prevent the new threads from being cut correctly.

 

[ALANRIDER7]

The previous owner may have mixed up the bolts after having the cover off. Case covers have specific bolt lengths to hold them on, sometimes several different ones. If short bolts were put in the long holes, it's easy to pull the threads out. Double check the fasteners you have and make sure you've got the right ones in the right place, especially after helicoiling.

 

[JimE]

I would use helicoil if you expect to have the bike or take it anywhere dependably. Most goops and such like JB Weld will eventually come loose. Just keep the area clean when you drill and tap for the helicoil by placing rags, take moving bits out of the way, use a shopvac, and wipe down good at the end. This problem is common enough that you will probably find at least some 6M x 1.0 helicoils in mechanics toolboxes. That's probably what they are: 6M x 1.0 bolts. Also do pay attention to bolt length as it will vary around the cover. ALANRIDER7 is most likely correct....

 

[GetaGripGreg]

Helicoil is the way to go. Buy a kit that includes the drill bit and tap. Follow the instructions. Simple!

As said already, be careful to drill straight. When using the tap, go slowly and back the tap out a half turn every now and then as you go, to clean the swarf out of the tap. Use lube. When inserting the coil with the special tool, be sure to follow the part of the instructions that tell you to punch out the tang at the bottom of the coil when you are done.

If it is only weeping oil and not actually dripping, you could ignore it for a long while and just clean it more frequently. If it drips, you need to fix the threads to get proper clamping on the side cover.

 

[MOBILE WELDER]

You can try the HEL-COIL. If it doesnt work. the area can be weworked by filling the holes with weld metal and retapping. This would be a permant fix and Garenteed to work. Looking at two hours of work.
Robert

 

[mapes]

You can try the HEL-COIL. If it doesnt work. the area can be weworked by filling the holes with weld metal and retapping. This would be a permant fix and Garenteed to work. Looking at two hours of work.
Robert

Yes and no. Welding old crankcases leaves them porous sometimes and then they leak oil. Look obviously its a slight oil leak and the bolt will be lightly torqued. With that in mind I would try out the loc tite form a thread cause that seems the easy and cheapest and fastest way to fix this. Just try it out on something else first. If it seems likes it works then go for it. If it dosen't workj then you can still drill/heli coil or weld. Your not worried bout structural integrity your worried about oil leaking

 

[MOBILE WELDER]

Not true about welding old cases. If it is done corectly they will never leak. It all depends on the preperation and weld filler metal used.
ROBERT

 

[mapes]

I did say sometimes in that discription did I not? I'm just merely suggestiong that since the bike runs fine and has just a slight oil buildup not even a leak around that area why spend a lot of time or money on it.