Primary cover needle roller bearing failure

[sfcpiet]

What do you think, if I replace the crankshaft outrigger bearing and inner race, Loctiting the inner race in place, can I get another season's riding out of it while I have my spare crank rebuilt properly?

Generally speaking Ken, how's your luck?  Won the lottery lately?

Dunno if it will hold up, have no telepathic/clairvoyant skills that I know of, sorry!

You can check crank run-out when removing the cover with the following procedure.  Remove spark plugs, stick them in their leads and ground them.  Remove all cover fixing bolts and hit the starter button.  With little or no run-out, the primary cover will stay put, the gasket holding it tight to the cases, or move a mm or 2 at the most.  Excessive run-out will cause the cover to wobble off almost insantly..... Yes, and drain the oil before you start!

You can start by renewing the needle race on the shaft and fitting a new bearing in the cover.  Try fitting the cover without the chain tensioner, just to see how easy it slips on the 2 shafts.  Remove and turn the crank through 90? and try again.  It should be possible to push the cover on with only very light taps of a rubber mallet perhaps being needed.  If it slips on easy in all postitions, you may be lucky.  Either the crank hasn't as much run-out as you measured or the bearings are so shot that the journal moves around enough to allow the crank to mate up to the cover.  If it doesn't mate up easily, probably be best to stop there and do the job properly.

When replacing the race on the crank, inspect the crank closely where the race is seated.  You may find 3 shiny raised portions of metal at the outer end of the crank, file these back a little so as to ease fitting of the new race.  You can use Loctite to secure the race if it is loose on the shaft, but a series of punch marks will be needed to prevent it going on walkabout again.  Don't overdo it though, a firm tap is all that's needed, a gawdalmighty clout will distort the race and your problem will return faster than you thought possible.

HTH,
piet

 

[sfcpiet]

Ken,

Any progress??

The local crank shop (Falicon) has apparently never seen a crankshaft with C3 main bearings.  

Seem to remember finding C3 grade bearings in early Honda roller-bearing cranks........

piet

 

[mcnicol]

Piet

When I actually took the primary cover off I was very happy to see that it was only the inner race that had spun out, and I didn't need a new cover. I just got the welded one back from the machine shop yesterday, but he had my new bearing in case he needed it and I haven't put the undamaged race onto the end of the crank yet and measured runout. I know I need to turn the crank from the right side too (the 2.5 thou measurement did include the crank wobble as I turned it with a spanner on the left side, and a race that was worn), maybe I'll get that done tonight. Bit bloody cold in the garage at the moment though, only about ~4C. Not supposed to be this cold in coastal Florida!
If the crank is at or close to the limit I probably will just put it back together, and send the spare crank off for a rebuild. Gotta make a bombproof box and then weigh the whole thing to see what shipping will cost.
So I'm keeping my fingers crossed and hoping it's OK. I still have to polish out the grind marks from the welded cover before I can bolt it all back together. Then the polished cover will look so good I'll have to start polishing the other not so shiny parts. Buggar buggar buggar!

Ken

 

[Rusty Spokes]

Ken,

Any progress??

The local crank shop (Falicon) has apparently never seen a crankshaft with C3 main bearings.  

Seem to remember finding C3 grade bearings in early Honda roller-bearing cranks........

piet

And Ducati, Yamaha plus several others. C3 was used because it was less prone to damage from debris in the engine oil. The looser clearances would eject rubbish (metals) rather than grind them into the balls and races.

The filtering system on the older engines (like our Laverdas) is crude and the bearings need all the help they can get.

Newer designs with modern oil filtering are more tolerant. Probably why Falicon had not seen any C3 bearing on a crankshaft. 

C3 bearings won't make much difference when checking your run-out. Very slight. We are talking less than thousand of an inch of bearing clearance.

 

[jotajoe]

Piet

When I actually took the primary cover off I was very happy to see that it was only the inner race that had spun out, and I didn't need a new cover. I just got the welded one back from the machine shop yesterday, but he had my new bearing in case he needed it and I haven't put the undamaged race onto the end of the crank yet and measured runout. I know I need to turn the crank from the right side too (the 2.5 thou measurement did include the crank wobble as I turned it with a spanner on the left side, and a race that was worn), maybe I'll get that done tonight. Bit bloody cold in the garage at the moment though, only about ~4C. Not supposed to be this cold in coastal Florida!
If the crank is at or close to the limit I probably will just put it back together, and send the spare crank off for a rebuild. Gotta make a bombproof box and then weigh the whole thing to see what shipping will cost.
So I'm keeping my fingers crossed and hoping it's OK. I still have to polish out the grind marks from the welded cover before I can bolt it all back together. Then the polished cover will look so good I'll have to start polishing the other not so shiny parts. Buggar buggar buggar!

Ken

Hi Ken,

'scuse me for butting in ! I hope you sort out this problem without too much difficulty. I think you bought something off me a while ago on ebay from UK and it took the longest time to get to you..Did you ever get it ? I can't recall what it was now..but I remember you were very understanding and helpful to me,

cheers

joe

 

[motoddrob]

Hey Ken, there is a BMW crank guru in Texas that my Perth mate sends his old R60/69s cranks too for rebuilds. Apparently he's the Man for BM cranks. Have no idea if he does other cranks but could be worth talking to. I'll call my mate later today and ask for details.

 

[jotacorsa]

rob, ask your mate if the fellow is named perry

 

[mcnicol]

I think you bought something off me a while ago on ebay from UK and it took the longest time to get to you..Did you ever get it ? I can't recall what it was now..

Joe, almost everthing I buy from the UK takes forever to get here (except a swing arm that I think I must have paid overnight shipping on, it arrived in about 4 days, and boy did I pay a lot for that!). PM me with your eBay name and I'll look and see is probably the easiest way. I can think of at least 1 UK seller who didn't deliver, but that was a couple of years ago.

Ken

 

[motoddrob]

Scott, just spoked to my BM mate, the crank guys name is Chris Chambers, and apparently only does /2 cranks. Sort of semi retired. So probably not much to Ken then!!

 

[jotajoe]

I think you bought something off me a while ago on ebay from UK and it took the longest time to get to you..Did you ever get it ? I can't recall what it was now..

Joe, almost everthing I buy from the UK takes forever to get here (except a swing arm that I think I must have paid overnight shipping on, it arrived in about 4 days, and boy did I pay a lot for that!). PM me with your eBay name and I'll look and see is probably the easiest way. I can think of at least 1 UK seller who didn't deliver, but that was a couple of years ago.

Ken

Hi Ken..yes I am sure it was you ..If I rack my brains while drinking a strong cup of coffee it may come back to me..I am Swiftminnion on Ebay ...( I remember you are a teacher so pls excuse the incorrect spelling of that ! ). I've had parts for Australia take forever to get there..Anyway..let me know how that went in the end.I'd feel terrible if you didn't receive it  :'(....cheers,

Joe

 

[jotajoe]

I think you bought something off me a while ago on ebay from UK and it took the longest time to get to you..Did you ever get it ? I can't recall what it was now..

Joe, almost everthing I buy from the UK takes forever to get here (except a swing arm that I think I must have paid overnight shipping on, it arrived in about 4 days, and boy did I pay a lot for that!). PM me with your eBay name and I'll look and see is probably the easiest way. I can think of at least 1 UK seller who didn't deliver, but that was a couple of years ago.

Ken

Hi Ken..yes I am sure it was you ..If I rack my brains while drinking a strong cup of coffee it may come back to me..I am Swiftminnion on Ebay ...( I remember you are a teacher so pls excuse the incorrect spelling of that ! ). I've had parts for Australia take forever to get there..Anyway..let me know how that went in the end.I'd feel terrible if you didn't receive it  :'(....cheers,

Joe

was it a caliper mount for a Jota ? methinks ~ joe

 

[fast_eddie]

Just reading this thread this evening, concerned this is the reason why my primary cover is so hard to remove.

How do you measure "the crank run-out" ??

Is there a simple way with the bike on the stand or is this an engine out job?

Many thanks
Ed.

 

[sfcpiet]

Eddie,

Only need to remove the primary cover and somehow fix a dial guage to the cases to measure the crank at the needle bearing race.  Remove spark plugs and turn the engine by hand from the alternator side.

piet