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Crankshaft I.D. / Questions '72 TR6 650 #104428
10/31/06 1:42 am
10/31/06 1:42 am
Joined: Oct 2006
Posts: 83
J
Johnny Bones Offline OP
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Johnny Bones  Offline OP
BritBike Forum member
J

Joined: Oct 2006
Posts: 83
Hi, I guess I should start with an intro! My name is Johnny and I'm from near Pittsburgh, PA. I recently bought a '72 TR6 650 with a thrown rod. I took the engine completely apart, bought what I thought were all the correct parts to rebuild and ran into a problem.........dang.....
So here's my problem.... The crankshaft I bought is just slightly different. The flywheel is just a little bit different looking, but the big problem is that the part that goes through the bearing on the right side of the case is just a little too small in diameter. Can I get a different bearing with a smaller inner part?? If so any idea of the part #?? Not sure what this crank is out of, but the part #'s cast on the flywheel is E3906, and E4494 on the counter weights. Any idea what engine that's out of?? also any idea what the part # would be on the bearing for it???
Thanks!
Johnny

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Re: Crankshaft I.D. / Questions '72 TR6 650 #104429
10/31/06 2:03 am
10/31/06 2:03 am
Joined: Oct 2001
Posts: 541
Howard City, MI
E
Ed V Offline

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Ed V  Offline

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E

Joined: Oct 2001
Posts: 541
Howard City, MI
Johnny, the bearing you need is 70-1591. The original crank used a metric bearing and the one you have now uses an inch size.
Ed

Re: Crankshaft I.D. / Questions '72 TR6 650 #104430
10/31/06 3:15 am
10/31/06 3:15 am
Joined: Oct 2006
Posts: 83
J
Johnny Bones Offline OP
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Johnny Bones  Offline OP
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J

Joined: Oct 2006
Posts: 83
Will the inside diameter match the new crank and the outside match the case with no machining?

Re: Crankshaft I.D. / Questions '72 TR6 650 #104431
10/31/06 5:37 pm
10/31/06 5:37 pm
Joined: Mar 2005
Posts: 10,204
Boston, Massachusetts
J
John Healy Offline

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John Healy  Offline

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J

Joined: Mar 2005
Posts: 10,204
Boston, Massachusetts
The crank and crankcase are specifically machined to fit the inch and metric bearings. They must be fitted as a set. Metric crank, metric cases and metric bearing. Inch crank, inch crankcase, and inch bearing.

So the simple answer to your question is no.


Re: Crankshaft I.D. / Questions '72 TR6 650 #104432
10/31/06 9:38 pm
10/31/06 9:38 pm
Joined: Oct 2006
Posts: 83
J
Johnny Bones Offline OP
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Johnny Bones  Offline OP
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J

Joined: Oct 2006
Posts: 83
This sounds like it's gonna get expensive......

Re: Crankshaft I.D. / Questions '72 TR6 650 #104433
10/31/06 9:57 pm
10/31/06 9:57 pm
Joined: Aug 2006
Posts: 117
Fife,Scotland, UK
Grin Offline
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Grin  Offline
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Joined: Aug 2006
Posts: 117
Fife,Scotland, UK
All you have to is sell the crank you got and buy a T140 crank its essentially the same as the crank that was fitted as std to your 1972 T120.
The T140 crank will probally be easier to find and it fits straight in.
Then you can use the suprblend timing side mainbearing which is superior to the std ball race that was fiited on the timing side.
Grin

Re: Crankshaft I.D. / Questions '72 TR6 650 #104434
11/01/06 1:12 am
11/01/06 1:12 am
Joined: Oct 2006
Posts: 83
J
Johnny Bones Offline OP
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Johnny Bones  Offline OP
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J

Joined: Oct 2006
Posts: 83
What year T140 cranks will fit? By the way...I'm new at this....what is a T120 or T140....Is a Trophy TR6 also a T120??? How does that work?
Thanks,
Johnny

Re: Crankshaft I.D. / Questions '72 TR6 650 #104435
11/01/06 4:17 pm
11/01/06 4:17 pm
Joined: Aug 2006
Posts: 117
Fife,Scotland, UK
Grin Offline
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Grin  Offline
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Joined: Aug 2006
Posts: 117
Fife,Scotland, UK
Any T140 crank will fit,a T140 is a the codename for 750 Bonneville,T120 is the 650 Bonneville.
Those are the main 2,then you get all the slightley different ones a TR7 is a single carb 750 the TR6 is the single carb 650.
The letters after the numbers indicate the model type.
If you are new best get some books on the subject.

Re: Crankshaft I.D. / Questions '72 TR6 650 #104436
11/01/06 11:21 pm
11/01/06 11:21 pm
Joined: Mar 2002
Posts: 86
PA
don_dup1 Offline
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don_dup1  Offline
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Joined: Mar 2002
Posts: 86
PA
get a parts book and a workshop manual stop rask cycle in Evans City gary has them + parts and he is local.


DON
Re: Crankshaft I.D. / Questions '72 TR6 650 #104437
11/02/06 4:22 am
11/02/06 4:22 am
Joined: Oct 2006
Posts: 83
J
Johnny Bones Offline OP
BritBike Forum member
Johnny Bones  Offline OP
BritBike Forum member
J

Joined: Oct 2006
Posts: 83
I just took my crankshaft up there to Rask today and they said they could save the original one! That solves the bearing problem! I oughta have the crank back in a week or so.
I did buy the shop manual that Gary suggested, but it's a little vague and doesn't mention part #'s at all. This is how I learn though!
I'll have an update for you guys soon!
Johnny


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