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splitting T140 cases #781149 08/11/19 1:11 am
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Curmudgeon Offline OP
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Trying to split the cases on '76 Bonnie which threw the left rod. I want to remove the left case to inspect for damage but after removing every bolt I can see plus tach drive, the cases will not come apart. Suspecting the left crank bearing does not want to budge but maybe I'm missing something that I'm not aware of. Appreciate advice before breaking out the torch.


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Re: splitting T140 cases [Re: Curmudgeon] #781160 08/11/19 5:40 am
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reverb Offline
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...hello, that s normal; you need to do couple of whacks with a rubber mallet in spot places that are evident and sometimes use kind of a wedge or other to make a lever in the joint.
Of course, but obvious, is that bolt near the top.

Re: splitting T140 cases [Re: Curmudgeon] #781174 08/11/19 9:40 am
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Hold it up a few inches and sideways over a big pile of rags or old mattress and use a neoprene hammer on the end of the crank while holding the top case only. You need to protect the rods and take care, avoid alcohol and drugs blah blah

Re: splitting T140 cases [Re: Curmudgeon] #781192 08/11/19 4:02 pm
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dave jones Offline
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Are there the screws in the crankcase mouth on a T140 like on a 650?

Dave

Re: splitting T140 cases [Re: dave jones] #781193 08/11/19 4:30 pm
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triton thrasher Offline
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Originally Posted by dave jones
Are there the screws in the crankcase mouth on a T140 like on a 650?

Dave



Well there’s no harm in looking!


Amateur Loctite enthusiast.
Re: splitting T140 cases [Re: Curmudgeon] #781195 08/11/19 4:52 pm
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750's don't have the screws at the crankcase mouth, that area has been machined away to accept the larger siamesed cylinder spigots. The later 750's do, however, have a hollow alignment dowel at the front engine mount that 650's do not. The dowel is quite long, 2" or 3", and can really hold the cases together.

Eric


1971 T120RV (R.I.P.)
1973 T140V/TR7
1993 Ducati 900 SS
Re: splitting T140 cases [Re: Curmudgeon] #781196 08/11/19 5:32 pm
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John Healy Offline
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As BikeVice mentioned starting on later 1976 models there is a 2" long dowel in blind holes at the front of the crankcase. It is the located in the hole where the exhaust pipe brackets are attached.

It is subject to corrosion and can be a bugger to separate the case when it does. The worst one I did I had to drill it out. This means drilling into the aluminum to reach the dowel as ut sits inside a blind hole only accessable from the inside.

Heat in the are can help to release it.


Re: splitting T140 cases [Re: Curmudgeon] #781198 08/11/19 6:26 pm
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Hugh Jorgen Online Content
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Speaking of splitting cases, may I hijack this thread momentarily?

No provenance on bike, so not sure how long it sat.
Now running near daily and leaks starting to appear.
Oil weeping from both nut ends of 5 1/4" stud running across lower front of cases.

I plan to split the cases at some point, but in the interim, am I asking for grief by backing those nuts off and sticking some HondaBond in there?
Or just let it weep till the job is done proper?


1970 T120R
Re: splitting T140 cases [Re: Curmudgeon] #781199 08/11/19 6:30 pm
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triton thrasher Offline
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Yeah put sealant under the washers.


Amateur Loctite enthusiast.
Re: splitting T140 cases [Re: BikeVice] #781212 08/11/19 9:25 pm
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Tigernuts Offline
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Originally Posted by BikeVice

750's don't have the screws at the crankcase mouth, that area has been machined away to accept the larger siamesed cylinder spigots. The later 750's do, however, have a hollow alignment dowel at the front engine mount that 650's do not. The dowel is quite long, 2" or 3", and can really hold the cases together.

Eric


Yes, that's almost certainly what the sticking point is. Sometimes heat will get the dowel to shift but occasionally, you need to drill the bastard out. It won't be the fit of the drive side main bearing as this is a roller, so will come apart with ease. If you definitely have all fasteners removed (including the long bolt with its head near the gearbox cavity), the dowel is the only candidate left.

Last edited by Tigernuts; 08/11/19 9:25 pm.

If anything other than a blank space is visible here, something's wrong.
Re: splitting T140 cases [Re: Tigernuts] #781216 08/11/19 10:08 pm
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quinten Online Happy
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..................
dowel pin is # 3
.................

[Linked Image from nvt-motorcycles.com]

Re: splitting T140 cases [Re: Curmudgeon] #781220 08/11/19 10:46 pm
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reverb Offline
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Hello Bikevice; I have 2 T140E with the bolt under the mouth; so do not know what bolt do you say.

Re: splitting T140 cases [Re: Curmudgeon] #781221 08/11/19 10:48 pm
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rather than whack the cases apart, a gentler way of applying force is a three-way puller. i recently tried to do it dsifferenty and took a T120 apart using a harmonic balancer puller in the stator holes. i think i posted this picture

[Linked Image from i.imgur.com]

that's a piece of angle aluminum between the end of the crakshaft stud and the puller spindle. banging on the crank end can smoosh it out shape.

triumph used to sell a tool to do it this way, and it wouldn't be hard to make one.


every day you do not take a chance is a day of your life that you will never get back.
Re: splitting T140 cases [Re: Curmudgeon] #781223 08/11/19 11:16 pm
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Did you remove the nut and bolt shown as 16 & 43 in the diagram? Need to take gearbox inner cover off for access.


1966 Triumph Thunderville
1968 BSA B40M Roughrider
1970 TR6C
Re: splitting T140 cases [Re: Tigernuts] #781229 08/12/19 12:29 am
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Wow, this is the first time I've heard about this damn dowel.


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Re: splitting T140 cases [Re: tiger_cub] #781291 08/12/19 5:59 pm
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You nailed it on the head tiger-cub! I had neglected to remove the bolt and the nut just forward of the transmission. After I did that I was able to get the left case off. Thanks to you and Morgan! Great forum!


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Re: splitting T140 cases [Re: Tigernuts] #781309 08/12/19 8:25 pm
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Tigernuts Offline
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Originally Posted by Tigernuts
[quote=BikeVice] Did you see my post? It said:-
...If you definitely have all fasteners removed (including the long bolt with its head near the gearbox cavity), the dowel is the only candidate left.


If anything other than a blank space is visible here, something's wrong.
Re: splitting T140 cases [Re: triton thrasher] #781313 08/12/19 9:14 pm
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Hugh Jorgen Online Content
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Originally Posted by triton thrasher
Yeah put sealant under the washers.

That sorted it.
Thanks!


1970 T120R
Re: splitting T140 cases [Re: Curmudgeon] #781330 08/13/19 1:31 am
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Hi Curmudgo, What did you find for a dowel on the front motor mount hole?

I found some T140 doesn't have blind dowel, but a long dowel that is fairly tight press fit.

I made puller by grinding down bolt head to a slip fit in alloy. Long bolt. Cut a spacer tube of 1/2" steel pipe longer than dowel by 1/4".

Put bolt through motor mount, tube over bolt, large flat washer. Ground a flat on end of threads to keep bolt from spinning. Installed nut & counter held bolt, then turned nut. Dowel pulled out very nicely with no damage. Some use allen head bolt so use allen wrench to counter hold. I've made some on lathe which is really easy, but grinder does work fine, just go easy to keep it round. Grind until head will just pass through the alloy. Dowel is usually flush on one side, so look close. I know you got it apart now.

Part & for dowel is 71-3989. Not shown in my parts book. Do eBay search with part # & you'll see it.
Don


1973 Tiger 750
Re: splitting T140 cases [Re: TR7RVMan] #781333 08/13/19 1:55 am
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Curmudgeon Offline OP
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OK, this is a '76 T140 and there is a dowel at the front engine mount. It looked fine, no corrosion to speak of so that was not an issue. A couple of the guys here mentioned a bolt and a nut in front of the transmission cover and after pulling off the inner cover I was able to access them for removal. That did the trick. Thanks to all!


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Re: splitting T140 cases [Re: Curmudgeon] #781355 08/13/19 7:14 am
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TR7RVMan Offline
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Hi Crumudgeo, Thanks for the reply.

Was the dowel the long one 71-3989?

Would it have been able to slide out with the tool I made above?

This dowel has been a real fight on many motors.

Good you got it apart without damage.
Don


1973 Tiger 750
Re: splitting T140 cases [Re: TR7RVMan] #781379 08/13/19 2:52 pm
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Curmudgeon Offline OP
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Yes, that was the dowel.


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