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knuckle head
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knuckle head
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I always say if you use a shop enough times they will screw up......I installed .020 timing bushing in the warmed case using a hydraulic presss. I told the shop to check the bushing and hone it if necessary to make sure it's round and has no burrs...Well they dropped the ball, the bushing has .0028 clearance when I asked for .0015.....The .0015 clearance was told to me by several BSA tuners....
So, will the increse in clearance cause low oil pressue issues?
Any of you have actual experience with these bushing clearances? thanks


79 T140D, 96 900M Ducati ,61 A10 .On a bike you can out run the demons..
“But I don't want to go among mad people,” Alice remarked. “Oh, you can't help that,” said the Cat: “we're all mad here. I'm mad. You're mad.
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Originally Posted by Hillbilly bike
So, will the increase in clearance cause low oil pressure issues?

Yes, you have double the leakage area so double the loss of oil out of the journal sides. So less flow to the crank and lower pressure.

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Hi Tony,
"Back in the day" 0.003" was reckoned to be the upper limit for clearance.
Greater than that it was new bush time and maybe reground crank journal depending on wear etc.
Sorry!
HTH

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knuckle head
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knuckle head
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oh ok, so at nearly .003 clearance my fresh engine is worn out before it's started..I'll get a solid bronze .030 bush, turn it close in the lathe , press it in and use the shop I used to use to hone it to size...It's only time and money....


79 T140D, 96 900M Ducati ,61 A10 .On a bike you can out run the demons..
“But I don't want to go among mad people,” Alice remarked. “Oh, you can't help that,” said the Cat: “we're all mad here. I'm mad. You're mad.
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You could switch to thicker oil wink


Now let’s all have a beer beerchug

68’ A65 Lightning “clubman”
71’ A65 823 Thunderbolt (undergoing restoration)
67’ D10 sportsman (undergoing restoration)
68’ D14 trials (undergoing transformation)

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knuckle head
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knuckle head
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Thick oil, lol.....something is strange here with a .010 Kibblewhite bushing that has not been honed should be 1.365..The crank journal measures 1.366....Maybe the mike's have been dropped too many times....will recheck with different measuring tools...


79 T140D, 96 900M Ducati ,61 A10 .On a bike you can out run the demons..
“But I don't want to go among mad people,” Alice remarked. “Oh, you can't help that,” said the Cat: “we're all mad here. I'm mad. You're mad.
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Wasn't that John H. that said something like; a man with 1 micrometer always knows how big something is. A man with 2 micrometers never does.

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Oh man, I would be so pissed at them! That's really frustrating...

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Originally Posted by leon bee
Wasn't that John H. that said something like; a man with 1 micrometer always knows how big something is. A man with 2 micrometers never does.


That's hysterical! 🤣

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Tony, A couple of things which may get me in trouble here. The bushing should not need to be pressed in. I heat the case in my outdoor grill to 300+ and have the bushing in the freezer. I made a tool that fits close ish in the bush. this provides a guide and holder. They are in the freezer as an assembly. Many times it just drops in. sometimes a light tap on the holder. While, in a perfect world, .0015 is fabulous so long as the thing is perfectly aligned, I don't think .0028 is going to be a problem. While 20-50 is kind of the standard, heavier straight oil can deliver more pressure. Since it is all apart why not tap for a pressure gauge. and do some experimenting? PRT

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knuckle head
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knuckle head
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Thanks Tom, I did tap for a port.....I just ordered a new 2 inch micrometer and small bore gauge..Slipping the crank into the case half it feels like less than .003....My local go to balancing guy says his balancer machine stands do not adjust for the difference in the crank drive and timing journals. Have to make a sleeve to equalize sizes on my 65 year old lathe .I will solve these problems....


79 T140D, 96 900M Ducati ,61 A10 .On a bike you can out run the demons..
“But I don't want to go among mad people,” Alice remarked. “Oh, you can't help that,” said the Cat: “we're all mad here. I'm mad. You're mad.
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Originally Posted by leon bee
Wasn't that John H. that said something like; a man with 1 micrometer always knows how big something is. A man with 2 micrometers never does.
I'm doomed, I have three micrometers. Of course no two can be used to measure the same thing as they are 1", 2" and 3". I do need to practice with the reference slug to get the feel for how tightly to turn the barrel. I still haven't figured out how to shove a 0.002" feeler gauge into the gap without destroying the blade. I do wish that I didn't need to check the work of every machinist I hire.

Originally Posted by Allan G
You could switch to thicker oil wink
Maybe some of that 70 weight aircraft oil that old Harley dudes use? laughing


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Originally Posted by DavidP
Originally Posted by Allan G
You could switch to thicker oil wink
Maybe some of that 70 weight aircraft oil that old Harley dudes use? laughing


You’d be surprised how many owners simply use a higher viscosity grade oil just to quieten the motor down.

Thii ok ugh choosing the right viscosity is important. There was a post on face-ache the other month where a fellow was stating he used something like 5-30. He was also one of those guys that was a mechanic for Aston Martini so knew everything about oil... or at least as much as what the autodata could tell him.


Now let’s all have a beer beerchug

68’ A65 Lightning “clubman”
71’ A65 823 Thunderbolt (undergoing restoration)
67’ D10 sportsman (undergoing restoration)
68’ D14 trials (undergoing transformation)

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Originally Posted by pushrod tom
Since it is all apart why not tap for a pressure gauge.....? PRT
Excellent suggestion.

Look into 1/16" pipe fittings and tap because there it scant room and wall thickness to work with. 1/8-npt is just too big. Position your port to avoid the frame loop too.

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knuckle head
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No problem on an A10 with 1/8 NPT, you have to know where to drill at what angle...


79 T140D, 96 900M Ducati ,61 A10 .On a bike you can out run the demons..
“But I don't want to go among mad people,” Alice remarked. “Oh, you can't help that,” said the Cat: “we're all mad here. I'm mad. You're mad.
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Originally Posted by Hillbilly bike
No problem on an A10 with 1/8 NPT, you have to know where to drill at what angle...
Glad it worked out.
I've drilled a few, usually from the lower front of the OP relief valve boss and those tiny little 1/16-npt fittings seemed a lot easier to work with.
Where did you drill?

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knuckle head
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6 threads are enough in this situation.. I have junk cases I drilled first...

20210320_164240.jpg

79 T140D, 96 900M Ducati ,61 A10 .On a bike you can out run the demons..
“But I don't want to go among mad people,” Alice remarked. “Oh, you can't help that,” said the Cat: “we're all mad here. I'm mad. You're mad.
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Yep, that's the spot. I must have been thinking of the A65 when I said "lower front."

Good thinking doing a trial run. You probably used a shortened tap to get the threads how you wanted them.

You are going to run steel rods if I remember right. That will help OP too because big end clearance doesn't grow as much.

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Originally Posted by Allan G
Originally Posted by DavidP
Originally Posted by Allan G
You could switch to thicker oil wink
Maybe some of that 70 weight aircraft oil that old Harley dudes use? laughing


You’d be surprised how many owners simply use a higher viscosity grade oil just to quieten the motor down.

Thii ok ugh choosing the right viscosity is important. There was a post on face-ache the other month where a fellow was stating he used something like 5-30. He was also one of those guys that was a mechanic for Aston Martini so knew everything about oil... or at least as much as what the autodata could tell him.


The last few years i raced my old beezer i ran R30 which is 30 weight, it was excellent oil as far as wear was concerned.
Despite everyone saying it's too light for 40+ deg ambient i never had any problems with oil pressure or smoking. It flows
great from cold which is really important. BUT then i never had any problems with pump petrol either whereas some say
you must run methanol here.
The main noticeable difference between the oil i used previously and the R was..........
IT SMELLS LOVELY.

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knuckle head
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knuckle head
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Originally Posted by Stuart Kirk
Yep, that's the spot. I must have been thinking of the A65 when I said "lower front."

Good thinking doing a trial run. You probably used a shortened tap to get the threads how you wanted them.

You are going to run steel rods if I remember right. That will help OP too because big end clearance doesn't grow as much.
I chose R&R alumunum rods because they are only 8 grams heavier than stock....I got to measure these parts


79 T140D, 96 900M Ducati ,61 A10 .On a bike you can out run the demons..
“But I don't want to go among mad people,” Alice remarked. “Oh, you can't help that,” said the Cat: “we're all mad here. I'm mad. You're mad.

Moderated by  Allan G, Jon W. Whitley 

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