To Split a case or not to split a case…?

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Dukaccino
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To Split a case or not to split a case…?

Post by Dukaccino »

Hi all
I’m in the throws of replacing all the bearings in my basket case 750gt.
The motor has been sitting for a long time (unknown)
Virtually all bearings are to be replaced for bevels, clutch basket Wt etc.
But I’m hesitant to split the cases as the crank rolls well and there is no play there.

Is there some way of making this decision.
Should I split the case anyway and just do them all?

Cheers
Peter S
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Craig in France
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Re: To Split a case or not to split a case…?

Post by Craig in France »

Dukaccino wrote: Mon Oct 25, 2021 5:40 am <snip> Is there some way of making this decision.
Only your personal 'risk profile' :)

The problem is that it's very difficult to gauge the state of the big ends with the crank still in the cases ... And some will tell you, even with the crank still pressed together. So:

1. Are you prepared to press the crank apart and then reassemble it? This is NOT a job for the innocent. Do you have the necessary expertise, or access to someone who does?

And on the other side:
2. How ticked would you be if the big ends blew 5 miles down the road after you've completed the re-build of everything else?

There. I've opened the door. Let's see what anyone else says ...

FWIW:
I have always chosen not to open the cases on my second-hand bevels, singles or twins. Only my Vento had to be split later on, but that was because the bearing on the output shaft blew ... Maybe I've been lucky.
Dukaccino
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Re: To Split a case or not to split a case…?

Post by Dukaccino »

Thanks Craig,
You’re doing a good job of making me worry.

The bearings in the outer cases bevels etc .. seemed to be in average to poor condition.
Because it has been standing for a long time, some the oils have hardened an a couple of those bearing were stuck , due to ‘standing still disease’, not seized..
No bearing had run seized.

The bores are in very good condition , original 80mm , no perceptable wear. Strange really.
The pistons are good , but again the rings glued to the grooves. Got them out ok though.

So my logic is the motor had a short hard life…. And then left sitting
It tends to suggest the internal case bearings, big end and gear, are likely ok.
They are larger and can ingest a bit more rubbish than those smaller bevel bearings..

Anyway that’s the thinking … I’ll make a decision … sometime..

Cheers
Peter S
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Dukaccino
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Re: To Split a case or not to split a case…?

Post by Dukaccino »

Hi all
Decision made!
I put a telescopic magnet down thru the oil filler and drain holes….

The slugg that came our was full metal bits … too much …

Oh well .. a splitting we will go .. hi ho the merry oh..

Cheers
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BevHevSteve
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Re: To Split a case or not to split a case…?

Post by BevHevSteve »

wise choice IF you plan on keeping and enjoying (riding) your bike.....
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Steve Allen (925)798-BEVL[2385] Ride'm, Don't Hide'm
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Dukaccino
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Re: To Split a case or not to split a case…?

Post by Dukaccino »

Hi All
just to round out this topic.

Brook Henry (V2) is just down the road .. sort of .. I visited and left him with the cases.
So he is doing a complete VeeTwo big end and rods and rebuilding the box, sorting the lower bevels and then putting it all together.

A likeable sort of guy is Brook.

Cheers All
Peter S
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Re: To Split a case or not to split a case…?

Post by BevHevSteve »

BTW - taking the motor to Brook is a very wise choice.
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