1978 R80/7 engine removal

[IanBrown]

any advice on removing the front engine through-bolt on the frame? I removed the rear threaded rod no problem, but the front one isn't budging. The holes in the frame look so tight on the threads of the rod, makes me wonder if I need to somehow unscrew the thing.

Applied penetrating oil. Should I try heating up the frame on both sides and just hammer it (with nut on) from one side?
Sorry, can't seem to post pictures right now.

Ian

[schrader7032]

Try getting a floor jack and putting a little up pressure on the oil pan...not much, but just enough to take some of the load off and maybe creating a better alignment. Likely just stuck...penetrant is your friend along with time.

[srankin]

Getting an engine out of the frame can be a chore if you are by yourself. The jack works pretty well. Most likely once you get the strain off of things the bolt will slide out.

I had forgotten how heavy the engine is on an airhead until I removed mine a month ago. I did a strip job on it removing anything I could to lighten it so I could lift it out myself. My wife did the job of pulling the bolts out. Otherwise I would have used a jack or borrowed a scissor lift. St.

[skychs]

I agree with Schrader .... scissor jack or pole jack under the engine. Move it up and down just a tad until you find the sweat spot to remove the bolt. Sometimes it takes a little persuasion to get it started. I would use a metal rod/punch over whacking the nut on the end of the bolt.

Like ST said ... they are heavier than they look. I tried picking up my R75 engine and had to put it down.

[IanBrown]

thanks for the advice - I love how responsive everyone is here.
I do have a scissors jack under the engine, and can see the engine move up and down with the jack (got the rear bolt out this way), but I'll have another go at it this weekend.

Have it stripped down - gear box, valve covers, heads, cylinders all off, will be interesting to see how heavy it is...

Ian

[skychs]

With the transmission AND cylinders off its shouldn't be too bad. Good luck. Let us know how it goes. Photos are nice. In the past I have been saved by several people looking at the photos and finding something wrong. I use an old iPhone to take my photos. The images are small enough to post.

[IanBrown]

Finally got around to removing the timing cover - used a heat gun and lots of penetration oil - there was a lot of corrosion on the lower spindle (can still see it, haven't cleaned it up yet).
I've been reading opinions on replacing timing chains and bearings. Anyone want to weigh in? 52,000 miles on the bike, I was probably heavy on the downshifting (but that was 26 years ago....); and opinions on replacing the bearing while I'm at it? I feel like I have it apart now, might as well do it.
Oh, and the engine was heavy, but not bad stripped down. I have a wood assembly underneath because the oil strainer assembly protrudes below the crankcase.

[schrader7032]

Snowbum's article on timing chains:

https://bmwmotorcycletech.info/timingchain.htm

Pretty tough call on whether to replace or not. I don't think it's easy to say something is worn or not. Some of the wear is going to be on the sprockets with the sides of the teeth getting cupped or thinned. The crankshaft sprocket tends to wear more than the camshaft. As I recall special tools are needed to remove these sprockets...getting them back on requires heating the sprocket in a bath of oil so that it expands and will slip on more easily.

The original chain doesn't have a master link so likely a link will need to be cut to get it off...replacements will have a master link.

But at 50K miles the chain might be OK...extra engine braking might have accelerated wear. But still 50K is not much. If it were closer to 70-80K, it might be a no-brainer to do it. I have 110K on my /7 with original chain. I don't hear or feel anything, so I'll just keep motoring along. I'm fairly easy on my engine, though. I think you're in a position with a tough decision and will need a commitment. Do you want to be back in here after another 20-30K miles...maybe 50K miles? Or should you bite the bullet and get it done so it's bullet proof for the next 100K miles?

Be sure and block the crankshaft if you plan on proceeding with chain replacement!

[IanBrown]

Thanks Kurt, I appreciate your input. Sometimes I feel I should do everything, and then money or time intervene. Considering I haven't ridden this bike in 26 years and never took it apart this far before, I'm thinking I may just start reassembling and see what happens. The learning curve is steep the first time round; I think I could do everything I've done now in half the time. May as well have some fun on the bike rather than staring at it in my basement....

[srankin]

Ian, I can understand the learning curve, LOL, I am finishing up my overhaul of my bike and it is not my first time but I still do the three steps forward two back from time to time. There reason is I don't do this kind of thing on a regular basis and so forget things. I can say for certain, the Chilton's manual is almost useless for me as it covers so many different models, in brief bits but not the detail needed sometimes. That said, I will get back on topic.

I would not bother to replace the chain with the miles you have on the bike. I have the single row chain on my R80RT and it lasted 80K before the first change and that was after 80K miles of treating the bike like a liter class super bike while riding. The double chain is more durable so 50K miles is not a lot of miles on it.
As for bearings, same goes, don't bother unless you have run the bike out of oil at one time (you haven't so don't worry) or you have 550K miles on it not 50K. I am at 140K miles on my RS and 240K miles on the RT and the cranks, and main bearings are fine. Also, the bearings are not something I would want to do myself as a learning experience. They are best left to a good airhead engine shop to do. I do mean a good airhead shop, car engine shops may not get the job done right. But, I don't think you need to worry.

I think you will find once you get the spindle for the timing mechanism cleaned up, get it working properly and seal up any oil leaks and such, once back together you will have a fine system and a lot of good rides.

Thanks for keeping us up to date on your progress, Cheers, St.