R100 rt oil pan find
My recent project is a 1994 R100 RT. While striping down the engine I found a steel pin in the oil pan. The pin is 3.5 mm in diameter and about 10.5 mm long.
The only pin I see on the parts diagram seems to be a pin for the con rod bearing.
Bike had a bad transmission but was running then I bought it last week. I will be putting in push rod tube seals so I'll get a look at the internals.
??? Thanks for your comments.
Tom Cutter posted some of a pin which is similar in size. It goes into the front main bearing carrier...if it comes loose, the main bearing can rotate around and that won't be good. He said he'd seen it on the '91s but someone also saw it on some '89s. Tom indicated that only way to find the pin location is to remove the timing chain and sprocket.
There are needle bearings in the rocker arm...not sure of their dimensions.
Its not a rocker arm needle bearing, They are smaller in diameter and longer. If it is from the mian bearing keeper I wonder how it came out. Maybe the PO removed the clutch assembly and did not block the crankshaft??
The part you found is most likely the locking pin for the front main bearing. It is retained by light peening in the housing, and if not sufficiently captured simply pops out of its bore. If the bearing moves, oil to the rocker is shut off. The loss of the pin also creates an internal oil leak, lowering pressure to the crankshaft.
It is possible to remove the front bearing housing while the motor is in the frame and without complete engine disassembly.
[QUOTE=Davis2x1;825677]If it is from the mian bearing keeper I wonder how it came out. Maybe the PO removed the clutch assembly and did not block the crankshaft??[/QUOTE]
Not blocking the crankshaft is only a problem if you remove the flywheel, not just change the clutch, and then it affects thrust washers at the back of the crank. I think the issue with the front main bearing pin is it was a "bad day" at the factory kind of thing. As mentioned, they're supposed to be peened in place...if the peening wasn't done right, the pin can back out.
Thanks for the information. I'll try to pull the front bearing carrier off tomorrow. The engine is out of the frame so I can stand it up on the clutch end. Hopefully I can reinstall the pin and stake it in place.
Attached photo shows pin found in oil pan and where it belongs. The photo is the back side of the front main bearing carrier. As you can see I was lucky that the bearing did not spin in the carrier.
Thanks to "lostboy" for making the right call.
They rarely spin, which would destroy the carrier and bearing. However, the bearing will occasionally move enough to shut off the oil to the rockers.
I stopped using the OEM pin years ago; instead, I use a 5mm bolt with the end ground flat and Loctite it in.