Help! Lower Engine Mounting Bolt

[jons]

Hello all,

I've searched and can't find anything - so hopefully someone can help.

I'm trying to remove an L9 engine, and all was going fine until I got to the lower mounting bolt. The nut came off easily, but I can't shift the bolt. Am I missing something obvious? I've a tried long ratchet handle with all my weight on it (= bent ratchet), spanner with persuasion from a large hammer, tapping it through from the other side, other mounts tight, other mounts removed, all engine weight on the frame, all engine weight supported and combinations of all these - but it won't shift.

I've run out of ideas now - so please let me know if you have any advice.

Thanks.

[CaNsA]

Any circlips in place?

[banner001]

L9 is the same mounting as the other L models, its just a nut on the end of a long bolt.

Once the nut is off the bolt should be able to be turned with a ratchet/extension bar etc. can you do this? or is this how you bent the first one?

sounds like the bolt may be bent, has the bike been in an accident, any damage to the frame etc? it should just tap out from the other side. even if the full weight of the engine is pressing on it it should still tap out without any problems.

Does it look excessivly rusty, or has the bike done tens of thousands of UK winter riding?

[jons]

L9 is the same mounting as the other L models, its just a nut on the end of a long bolt.

Once the nut is off the bolt should be able to be turned with a ratchet/extension bar etc. can you do this? or is this how you bent the first one?

sounds like the bolt may be bent, has the bike been in an accident, any damage to the frame etc? it should just tap out from the other side. even if the full weight of the engine is pressing on it it should still tap out without any problems.

Does it look excessivly rusty, or has the bike done tens of thousands of UK winter riding?

That's what I thought - must be bent or seized from years of road salt. It looks ok though, no obvious rust or corrosion. I think this frame's straight, it's my other one that isn't and the bolt moves OK on that one! I'll apply some penetrating oil then find a bigger hammer...

Any circlips in place?

I replied to this yesterday, but it seems to have disappeared (or I hit the wrong button)... anyway I think banner001 has answered the circlip question

[Ewetea]

The bolt sits just in front of the rear wheel, so as you surmise, years of being soaked by rain and salt have resulted in a chemical action between the bolt and the alloy crankcase. There is an open section on the crankcase allowing this to happen. Penetrating oil will not penetrate sufficiently to release it. I had a similar situation. I tried cutting the head off the bolt and then using the nut on the other end to pull the bolt through, without success - it wasn't budging. So I cut through the bolt in the open section by drilling through it (there is insufficient room to use a hacksaw) and used the nut to pull out the threaded end. Then, with all engine bolts out I levered the free side forward to permit the remainder of the bolt to slide out of its support flange. The remainder of the bolt was then drilled out, although it was very tricky starting in the middle and drilling square. It might sound a little drastic, but it worked.

[jons]

The bolt sits just in front of the rear wheel, so as you surmise, years of being soaked by rain and salt have resulted in a chemical action between the bolt and the alloy crankcase. There is an open section on the crankcase allowing this to happen. Penetrating oil will not penetrate sufficiently to release it. I had a similar situation. I tried cutting the head off the bolt and then using the nut on the other end to pull the bolt through, without success - it wasn't budging. So I cut through the bolt in the open section by drilling through it (there is insufficient room to use a hacksaw) and used the nut to pull out the threaded end. Then, with all engine bolts out I levered the free side forward to permit the remainder of the bolt to slide out of its support flange. The remainder of the bolt was then drilled out, although it was very tricky starting in the middle and drilling square. It might sound a little drastic, but it worked.

Sounds like you have more skill with a drill than I have, I can't see how to get enough access to the middle section of the bolt to drill/cut it. After several hours of swearing at it, right now I quit! Anyone want 2 L9s for a winter project?

[Ewetea]

Put a couple of axle stands under the lower "beam" of the engine to support the bike, and then remove the rear wheel and swinging arm to permit plenty of room to access the bolt. Centre punch the bolt very near the end with the head, and use progressively larger drills to "cut" the bolt. Then use a nut and washer on the threaded end to pull that section of the bolt out. Once it starts moving it can be grabbed with pliers and wriggled out. When I did the job I suspended the back of the bike from a roof strut in the garage. Since the axle stands will be close together, there is the possibility that the bike could fall over if nudged, so take appropriate precautions.
Since the bolt is seized, there is also a possibility that the swinging arm bolt is also seized!!!!! You'll be able to unfasten the nut, but the bolt will just turn and not slide out, even with persuasion from a hammer and copper drift. I encountered that problem too, and had to tackle it in the same way as the bolt: drill the head off and then use the threaded section to pull it out.
Don't give up! Life is full of problems, but walking away doesn't solve them. While you have the wheel and swinging arm out you can check the bearings in both, and also the linkage between the swinging arm and the frame - it's likely that the one of the needle roller bearings will be shot. This is all part of the winter rebuild in preparation for summer riding.

[jons]

I was thinking of just rebuilding the topend, I think I should be able to do it in the frame. But you're right, I'll need to strip the rear end anyway so I may as well do it now. I have an Abba stand that will make it a bit easier. Also wondering if I'll be able to attack the bolt with the dremmel once the swingarm etc are out of the way. It's drilling out the last bit once the engine's out that I'm more concerned about, but what's the worst that can happen!

[Ewetea]

Well done! If you can remove the upper rear engine bolt, and the two at the front, you should be able to swing the engine a little way out of the frame, pivoting on that wretched lower rear bolt. This will gave you more room for the top end rebuild.
Happy Christmas!

[RedexRobB]

Just take the bolt out and drop the lot.

[jons]

Just take the bolt out and drop the lot.

Hadn't thought of that. Thanks for your input.