Samuel -
As you suggested, rings and valves...valve guides should be included. The oil that makes it to the valve cover area must drain back through holes in the lower part of the head and cylinder. Possibly if they were blocked, oil would have filled up to a point it was getting easily into the valves or guides.
The only other thing I can think of is a cracked head.
Kurt in S.A.
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oil leak left cylinder
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schrader7032
- Posts: 9065
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oil leak left cylinder
Kurt in S.A.
'78 R100/7 '69 R69S '52 R25/2
Fast. Neat. Average. Friendly. Good. Good.
'78 R100/7 '69 R69S '52 R25/2
Fast. Neat. Average. Friendly. Good. Good.
update
Ok,
I took the offending head and removed the valve keepers using valve depressing tool, and using a dial gauge, and the measuring technique depicted in the Clymer manual, the intake play was .006, and the exhaust was an appalling .015, these appear to be the original non rotating valves. the heads at this point at least don't appear to have any large cracks, the valves don't appear to have severe recession. Has anyone here replaced the valve guides themselves? what about resurfacing/replacing the valve rings ? I remember reading about it somewhere but I just cant remember where. what would you guys do?
thanks again,
Samuel
I took the offending head and removed the valve keepers using valve depressing tool, and using a dial gauge, and the measuring technique depicted in the Clymer manual, the intake play was .006, and the exhaust was an appalling .015, these appear to be the original non rotating valves. the heads at this point at least don't appear to have any large cracks, the valves don't appear to have severe recession. Has anyone here replaced the valve guides themselves? what about resurfacing/replacing the valve rings ? I remember reading about it somewhere but I just cant remember where. what would you guys do?
thanks again,
Samuel
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schrader7032
- Posts: 9065
- Joined: Fri Oct 27, 2006 3:00 am
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oil leak left cylinder
I'm not familiar with the measurements you took. Could you explain what they represent?
As for guides, I've not done that before. If it were me and my lack of skills/knowledge, I would hand them over to a "professional" for their evaluation and refurb. I read in the new Barrington manual that the guides are drifted out of the heads after the heads are heated. New guides are installed in reverse order, heads heated and guides frozen. There's reaming involved to fit the valve stems. There are sizes of guides (stock, oversize) which may require that the hole in the head be reamed according. Also, there are different sizes of guides...the R50/2 takes 7mm guides.
What I don't see in the Barrington manual is how to determine if the guides need replacing and any way to verify the proper operation and tension of the springs. I've seen something like this for the /5-on models.
Kurt in S.A.
As for guides, I've not done that before. If it were me and my lack of skills/knowledge, I would hand them over to a "professional" for their evaluation and refurb. I read in the new Barrington manual that the guides are drifted out of the heads after the heads are heated. New guides are installed in reverse order, heads heated and guides frozen. There's reaming involved to fit the valve stems. There are sizes of guides (stock, oversize) which may require that the hole in the head be reamed according. Also, there are different sizes of guides...the R50/2 takes 7mm guides.
What I don't see in the Barrington manual is how to determine if the guides need replacing and any way to verify the proper operation and tension of the springs. I've seen something like this for the /5-on models.
Kurt in S.A.
Kurt in S.A.
'78 R100/7 '69 R69S '52 R25/2
Fast. Neat. Average. Friendly. Good. Good.
'78 R100/7 '69 R69S '52 R25/2
Fast. Neat. Average. Friendly. Good. Good.
guide wear testing
Ok, the measurements that I took were taken in this way:
1. heads off engine
2.remove valve retainers/caps/springs
3.set the head on a surface that allows the head to sit in a stable position, I used my drill press table because the valve cover stud and the valve rocker arm post line up with the holes in the table
4 after setting the head down, with the combustion chamber side up, and removing the valves set up a dial gauge so that it will measure the X axis(l front of head to back of head) ( I use one with a magnetic base and adjustable arm)locate the tip of the gauge down in the valve seat so it would be touching only the valve stem if it were there.
5. draw back the dial gauge point and set the valve into the guide, carefully lower the valve so that it is as far in the guide as possible without touching anything other than the contact point of the gauge when you return it to the stem, return gauge point to stem.
6. wiggle the valve and find the play for the x axis and measure the amount of total movement.
7. reset your jig to measure the Y axis( from top to bottom) and measure the total play.
I only gave a single measurement ( the poorest fit either X or Y ) for each of the guides. in this case both of the guides had the greatest wiggle on the X axis (front to back of head).
I hope that was clear enough to understand.
where is everyone ? is there free coffee somewhere?
Thanks,
Samuel
1. heads off engine
2.remove valve retainers/caps/springs
3.set the head on a surface that allows the head to sit in a stable position, I used my drill press table because the valve cover stud and the valve rocker arm post line up with the holes in the table
4 after setting the head down, with the combustion chamber side up, and removing the valves set up a dial gauge so that it will measure the X axis(l front of head to back of head) ( I use one with a magnetic base and adjustable arm)locate the tip of the gauge down in the valve seat so it would be touching only the valve stem if it were there.
5. draw back the dial gauge point and set the valve into the guide, carefully lower the valve so that it is as far in the guide as possible without touching anything other than the contact point of the gauge when you return it to the stem, return gauge point to stem.
6. wiggle the valve and find the play for the x axis and measure the amount of total movement.
7. reset your jig to measure the Y axis( from top to bottom) and measure the total play.
I only gave a single measurement ( the poorest fit either X or Y ) for each of the guides. in this case both of the guides had the greatest wiggle on the X axis (front to back of head).
I hope that was clear enough to understand.
where is everyone ? is there free coffee somewhere?
Thanks,
Samuel
-
schrader7032
- Posts: 9065
- Joined: Fri Oct 27, 2006 3:00 am
- Location: San Antonio, TX
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oil leak left cylinder
Samuel -
I sort of figured you were trying to measure something associated with the guides. I've never heard of a method to measure this...the value you read would depend on where on the stem you set your dial gage. Most what I've heard from the experienced wrenches is that they have a "feel" as to how much is too much when they rock the valve in the guide.
My workshop manual shows the ID of the guide for an R50 to be 7mm +0.005 - 0.010. That's probably the only definitive way to measure the guide and its wear and be able to compare to some standard. My Haynes manual for /5-on bikes says to check the valve guide for excessive play...it doesn't say how to do that.
From your measurements, one valve against the other, it would appear that one is much looser than the other. I couldn't say if it bigger than any standard though.
As for everyone else, maybe on the way to the MOA National rally in Tennessee? I'm off in the morning...just trying to kill the rest of the day before heading out.
Kurt in S.A.
I sort of figured you were trying to measure something associated with the guides. I've never heard of a method to measure this...the value you read would depend on where on the stem you set your dial gage. Most what I've heard from the experienced wrenches is that they have a "feel" as to how much is too much when they rock the valve in the guide.
My workshop manual shows the ID of the guide for an R50 to be 7mm +0.005 - 0.010. That's probably the only definitive way to measure the guide and its wear and be able to compare to some standard. My Haynes manual for /5-on bikes says to check the valve guide for excessive play...it doesn't say how to do that.
From your measurements, one valve against the other, it would appear that one is much looser than the other. I couldn't say if it bigger than any standard though.
As for everyone else, maybe on the way to the MOA National rally in Tennessee? I'm off in the morning...just trying to kill the rest of the day before heading out.
Kurt in S.A.
Kurt in S.A.
'78 R100/7 '69 R69S '52 R25/2
Fast. Neat. Average. Friendly. Good. Good.
'78 R100/7 '69 R69S '52 R25/2
Fast. Neat. Average. Friendly. Good. Good.
oil leak left cylinder
well, the deeper I get the more it looks like the engine has been opened a few times, small dings in the case where the rods would hit if one wasn't careful, and non original rings, that are out of spec, when placed evenly in the bore the .017 gauge slides right through. I think it may still have the original pistons although I am not sure. I believe the Clymer manual says it should have 4 rings but these only have three. it looks like its got more than the 16*** that is stated on the odometer, how unusual. I have started the process of engine removal to take a look at whats inside, I can only hope a perfect crank, and the sundry requirements to make that possible. I suppose I will work on the final drive oil migration solution while I order more tools and parts. how long should rings last?
All the best,
Samuel
All the best,
Samuel
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schrader7032
- Posts: 9065
- Joined: Fri Oct 27, 2006 3:00 am
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oil leak left cylinder
Samuel -
I've got about 75K on the rings on my /7. I'm probably looking at a top end, not just for rings, but valves, seats, etc. But I would think that rings could go from 50K to 100K depending on use/abuse, etc.
Kurt in S.A.
I've got about 75K on the rings on my /7. I'm probably looking at a top end, not just for rings, but valves, seats, etc. But I would think that rings could go from 50K to 100K depending on use/abuse, etc.
Kurt in S.A.
Kurt in S.A.
'78 R100/7 '69 R69S '52 R25/2
Fast. Neat. Average. Friendly. Good. Good.
'78 R100/7 '69 R69S '52 R25/2
Fast. Neat. Average. Friendly. Good. Good.
-
Allan.Atherton
- Posts: 503
- Joined: Fri Oct 27, 2006 3:00 am
oil leak left cylinder
... I think it may still have the original pistons although I am not sure... it looks like its got more than the 16*** that is stated on the odometer, how unusual.... how long should rings last?..
I don't know if rings last as long as the pistons. Many times a motor is invigorated by a re-ringing and honing, so a piston can have two sets of rings. The pistons last as long as their wear plus the cylinder wear is under .12 mm.
That comes from the Workshop Manual, where a 1st overbore is not recommended until the clearance has worn to .12 mm over the assembly clearance, which is .05 to .06 mm for an R50-60 or .09 mm for an R69S.
For original pistons in a well-maintained motor, i.e. regular use and oil changes, you can estimate the miles from the wear. The gap between cylinder and piston increases .01 (1/100) mm for every 10,000 km. So 1st overbore can be due in normal use at around 12 x 10,000 km = 120,000 km = 72,000 miles.
For engines with long periods of storage, intermittent use, and infrequent oil changes, the wear rate would be faster.
I bought an R69US with 9,000 miles showing, whose the pistons were marked 71.92 mm new, but actually measured at 71.90 mm, for a wear of .02 mm.
The original factory cylinder bore would have been 72.00 mm per the manual, but the bores actually measured at 72.03 mm for a wear of .03 mm.
So the piston to cylinder clearance had increased by .02 mm plus .03 mm = .05 mm, which means the motor had gone 5 x 10,000 km or 50,000 km or 30,000 miles if it had a good history. But the bike had a history of many owners and indifferent maintenance, so I expect the wear rate was faster and miles were actually around 25,000.
I don't know if rings last as long as the pistons. Many times a motor is invigorated by a re-ringing and honing, so a piston can have two sets of rings. The pistons last as long as their wear plus the cylinder wear is under .12 mm.
That comes from the Workshop Manual, where a 1st overbore is not recommended until the clearance has worn to .12 mm over the assembly clearance, which is .05 to .06 mm for an R50-60 or .09 mm for an R69S.
For original pistons in a well-maintained motor, i.e. regular use and oil changes, you can estimate the miles from the wear. The gap between cylinder and piston increases .01 (1/100) mm for every 10,000 km. So 1st overbore can be due in normal use at around 12 x 10,000 km = 120,000 km = 72,000 miles.
For engines with long periods of storage, intermittent use, and infrequent oil changes, the wear rate would be faster.
I bought an R69US with 9,000 miles showing, whose the pistons were marked 71.92 mm new, but actually measured at 71.90 mm, for a wear of .02 mm.
The original factory cylinder bore would have been 72.00 mm per the manual, but the bores actually measured at 72.03 mm for a wear of .03 mm.
So the piston to cylinder clearance had increased by .02 mm plus .03 mm = .05 mm, which means the motor had gone 5 x 10,000 km or 50,000 km or 30,000 miles if it had a good history. But the bike had a history of many owners and indifferent maintenance, so I expect the wear rate was faster and miles were actually around 25,000.
oil leak left cylinder
Well guys,
I am working on the 64' R50 and when I took delivery of the cycle , I started it it ran, rather smoothly, while making the list of things to take care of to get it mobile enough to discover the greater problems, I noticed that the area where the left head meets the cylinder was not just oily but noticeably wet, also while the engine was running I could see a slight disturbance in the oil that was sitting there, from what I attribute to escaping exhaust. when I removed the head I found that the piston and head were oily in addition to the usual carbon build up. obviously there are only a few ways that oil can get in the cylinder, my previous experience with "vintage" air cooled says, valves and/or rings, I am "new" to the fold, so is there a way for oil to migrate in any significant way from the push rod galleys to the combustion chamber? so while I wait for the Parcel truck, could anyone help me get the process of elimination straightened out? similar experience?
The speedo says 16*** which I am guessing is close because of the chain of ownership , history and documentation that came with the cycle.
Samuel
I am working on the 64' R50 and when I took delivery of the cycle , I started it it ran, rather smoothly, while making the list of things to take care of to get it mobile enough to discover the greater problems, I noticed that the area where the left head meets the cylinder was not just oily but noticeably wet, also while the engine was running I could see a slight disturbance in the oil that was sitting there, from what I attribute to escaping exhaust. when I removed the head I found that the piston and head were oily in addition to the usual carbon build up. obviously there are only a few ways that oil can get in the cylinder, my previous experience with "vintage" air cooled says, valves and/or rings, I am "new" to the fold, so is there a way for oil to migrate in any significant way from the push rod galleys to the combustion chamber? so while I wait for the Parcel truck, could anyone help me get the process of elimination straightened out? similar experience?
The speedo says 16*** which I am guessing is close because of the chain of ownership , history and documentation that came with the cycle.
Samuel
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