k1200rs oil control rings are WAY too big to go back into cylinder? - K-Bikes.com - Excellence in Motion
 
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post #1 of 5 (permalink) Old Mar 24th, 2020, 10:59 pm Thread Starter
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k1200rs oil control rings are WAY too big to go back into cylinder?

Hey guys, i have a 2001 k1200rs which i am in the process of rebuilding. The engine is disassembled and i am at the point of reinstalling the original pistons with the original rings into the original size bore. All 4 oil control rings are roughly 3mm too long and when installed in the bore will overlap by 2-3mm.
These are all original parts, that came out of the running engine, going back into the same engine. surely im missing something? i have the Clymer manual for this bike and theres no mention of weird oil ring fitment, or even any mention of oil ring end gap.
Any thoughts? cheers
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post #2 of 5 (permalink) Old Mar 25th, 2020, 6:23 am
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Doesn't make much sense. Original pistons, rings and cylinder bore? Have you tried to put the rings into the cylinder off of the pistons, by themselves? That should tell you if they will actually fit.

Frank

'17 R1200RS, 2 yrs. 30,000 mi.
'16 R1200RS, 18 mo. 28,000 mi. (gone)
'03 R1100S Boxer Cup Replika 6/200
'85 K100/1100RS, 35 yrs. 326,000 mi.
'05 R1200ST, 8 yrs. 57,400 mi.-3rd deer killed it.
'11 R1200RT, 2 yrs. 30,000 mi. (gone)
'99 R1100S, 2 yrs. 15,000 mi. (gone)
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post #3 of 5 (permalink) Old Mar 26th, 2020, 6:05 pm Thread Starter
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Yes its completely baffled me.
I have removed the oil control rings from the pistons and they do not fit in the bore even by themselves without overlapping 2-3mm. all four are the same.
The bore diameter is 70.5mm, the oil ring diameter (compressed with ends touching) is 71.8mm. I probably sound like a crazy person but these are the exact same oil rings that came out of this engine, but it was quite a while ago and i didnt take any notice of them at the time.
Surely anybody who has rebuilt one of these engines would remember if the oil rings fit in some weird manner?

FYI these are not 3 piece rings, its a strangely shaped one piece ring with a top and bottom ridge, connected at the base, with a stretchy spring that sits in between the top and bottom ridges, it is under tension and pulls the ring together when the spring is installed. Photos in the Clymer manual confirm that these are the correct rings but there is nothing describing the issue im having
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post #4 of 5 (permalink) Old Mar 26th, 2020, 8:01 pm
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Ben, have not done the job but have attached the relevant page from the BMW manual , it may help.
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post #5 of 5 (permalink) Old Mar 28th, 2020, 4:22 am
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Ben,

Which way did you remove the pistons?
Did they go out the crankcase side or did they go out the head side of the block.

Joe
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engine, k1200rs, oil control, piston rings, rebuild

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