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Broken Rod

David R

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I am finally putting my R1100 RT back together. I took rod caps off to plastigauge the crank. Here is what it looks like. I have poured babbit bearings, but I have never seen a rod like this. It only goes together one way. Bearings show little wear. I got .0015 to .00175" clearance with the old bearings. This motor is unbelievable at 130,000 miles. It had its first hundred thousand on Dino 10W40 changed every 3,000 miles.


Ring end gap with new rings is .008" at the top and ,007' at the base of the cylinder.


Here is the crank. Look like a little stuff has gotten through it.


I put in new bearings and bolts torqued properly.








This is a new timing chain guide. It has a little pad in front of the piston. The old one did not. I replaced both guides and the chain. The guides showed NO wear. Once I saw they changed it, I was glad I got the new one on the tensioner side. I put a new spring in the tensioner. The piston was out about 1/4" more with the old chain and guide.



I include a pic of the new timing chain




The old chain wrapped around the bottom sprocket A LOT more.


Those are original sprockets. They look great too.



Edit: I rode my Versys 550 miles in 2 days around the adirondacks saturday and sunday. The RT was the ride I wanted to take. I just got my heads back from the machine shop thursday. New exhaust guides and grind valves/seats. $400 pls tax. OUCH! I supplied the parts. As of tonight I have one cylinder on. The book says start on the right head, so I put piston on, cylinder and head all on the same side. I can crank the motor over once both pistons are in the cylinders I left the timing cover off till the heads are on. It won't be long now.....

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Evening David


That is pretty common on some engines now, called "fractured cap". That assures they only go back together one way & also locks the cap to the rod securely so it can't migrate around.


Make sure you mike or plastigage at a few places around the crank journals as the crank pins usually wear a bit egg shaped due to more wear near the top of compression & near top of firing stroke than on the coast around BDC.


Looks like you are getting close to getting it back on the road.


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Interesting. Thanks for posting.


Sounds like typical wear (or lack there of :) ) on a BMW made motor.


I stuck one of those telescopic cameras into the spark plug holes of my old '86 325es before I sold it to my nephew. It had somewhere close to 260K miles on it and had never had the head removed from the block. It burned a fair amount of oil, but you could still see the cross hatches on the cylinder walls from when it was originally manufactured.

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The bike is all toghether and I rode it for a few miles tonight. Tomorrow it goes for breakfast, then a ride. So far, no oil leaks, no knocks or other odd noises. It good to have it back.



While Assembling, the left side cam shaft is worn. The tappets or lifters or cam followers are pitted pretty good. Enough that its eating up the cam. I had to pull the right side back apart to inspect it. All is well on the right side.


I will put a hundred or two miles on it tomorrow then change the oil and filter.


Beemer bone yard has no cam shaft for sale.


I Have not been to BMW yet for their pricing.


I andjustd the valves after the engine had been cranked over to check for oil flow and pressure with no spark plugs. New battery PC80? New spark plug wires.


I put the manometer on it once it was running. I have been wanting a faster Idle, so I went to open the BBS on the left and it was frozen in place. I could not budge it even with a big screwdriver. I opened the throttle plate about 3/4 turn on the screw and backed out the BBS on the other side. Idle is now hot at 1050. give or take.


Right throttle shaft is loud.


It feels good to have it back.


More later.


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200+ Miles today. No problems,the noise I was originally hearing is gone. Motor runs smooth.


The bike runs almost no different than it did before. I did not crank it up past 5,000 rpm. It seems to have some more snap, but who knows.


Nothing but happy. I'm keeping this bike!


For the break in, I took a freind riding on the twisties I ride around here, but we took our time. Nice ride to practice turns slow.


I did solemn the dotted lines at 60 mph. Now that the motor is quiet, I can run it at 4,000 rpm in 4th gear and go about 60 mph. Things are smoother and the bike is a little more like a cat ready to pounce.


Oil and filter change tomorrow.


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Bike runs sweet. I found a camshaft on Ebone for cheap it includes the whole rocker box.


I have a leak at the front crankshaft seal. I did not know how to put it in. A "radial seal" was another thing I have not seen before. I have a standard seal with the measurements noted in the parts book on its way from NAPA.


500 + mile trip for this bike on Friday. Cam shaft should be here thursday, so I will be burning the midnight oil installing it. Next is adjust valves, Re adjust throttle bodies, change the oil and filter. Ride.


Its nice to have the ol girl back. :):)

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On the trip now. I ended up putting a GS cam in the left side. Once it was synced I cannot tell the difference. Timing is different on the GS cam.


Front seal was not leaking, I just left out 2 bolts for the cover. Bike rung great and is quiet.


No more knocking noise that starts at 3500 and gets worse as it goes up.


Now I can run the bike at 4,000 rpm. I have about 700 miles on the motor so far, I changed the oil and filter at 300 miles and will change it again after about 1,000 miles. Then its back to the regular schedule and hope fully another 100,000 out of it.


I now have a leak at the left side tensioner. It needs a new seal washer. I pulled it out to change the cam and now it leaks. Not a big deal. When I get home, I will replace the crush washer.


Life is good !


The job was worth the time and $ I put into it. I ended up with a rebuilt motor for $1500 including Odsy battery and new plug wires.

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Peter Parts

I guess these Oilheads aren't as dull as I thought. Rare privilege to read about a rebuild. Thanks.


In days of yore, engine work was pretty common and efforts to up the power routine. Today, not much scope to do mods and little published on how-to-do-it. Worse yet, when you are done,there is no scope at all to change timing or fueling, except by major part replacements.



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