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How to split a 2 stroke crankcases the cheap way


DirtyDT
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Disclaimer; Anything you do is YOUR responsibility, not mine.

Splitting 2 stoke crankcases is fairly simple. There are 2 main problems;you never know what the last owner did and; crankcase splitters are expensive and rarely used.

Method

Get the engine ready for splitting.

es1.jpg

While you are doing this get hold of the components you need to make the splitter. In my case;

2x 6M threaded rods and the old roof rack that was tucked down the back of the shed. Everything else you should have. The rods were about £8 from evilbay.

es2.jpg

Do some measuring, drilling and cutting until you get something like this

es3.jpg

Fit your new tool to the crankcase

es4.jpg

Evenly quarter turn the 4 bolts and repeat until the seal breaks

es5.jpg

Remember that this puts pressure on the engine crankcase where the threaded bolts are in the crankcase. If the engine has separated in parts but the back is sticking, spray with some plusgas and gently use a scraper and rubber mallet to tap the scraper. Gently!!!

All going well the cases will separate and you should be left with the two half's.

es6.jpg

Take pictures as you go, and gently does it. Cups of tea also help.

By drilling additional holes in the roof rack and a socket or piece of wood you can also use this methid to push out bearings.

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Addendum

Make damn sure you have removed every last srew from the cases before using mechanical means to part them, some engines have screws in concealed places ;)

Thats more or less the way i do my DT cases but using the bearing retainer screwthreads and pushing on the end of the crankshaft. :thumb:

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Addendum

Make damn sure you have removed every last srew from the cases before using mechanical means to part them, some engines have screws in concealed places ;)..........................

Ooooooh yes. Thanks OG. Very important.

Hopefully I will get most of the bearings and seals out later today :smash: and then look at the single blind one. Not a problem, I hope :D

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Whats wrong with a sledge hammer and a chisel then? :smash:

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Whats wrong with a sledge hammer and a chisel then? :smash:

Absolutely nothing, thats a fine method for these bikes........

XJ750 (UK) Spec.

750 MAXIM (US) spec.

Triumph bonnerville T120 650(Hagen frame)

AJS 250

JAWA 250(gone thank god)

Fanny B 200 single

Suzuki 350 thing, rust,more rust and more rust.

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Whats wrong with a sledge hammer and a chisel then? :smash:

You could go the full hog and hit the engine with an artic! Pictures would be good.

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Good tip DirtyDT

i"v found the rumble in the triple, it was bearing"s on drive-shaft, behind the clutch basket. , i thought it was behind sprocket on out- put shaft.. but will renew both,

& new R/h crank seal too,

P1000051.jpg

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Great stuff Blackhat, That rumble was moving all over the engine at the YOC weekend. I am glad you got it. That engine looks looooovly. Is it 40 years old now?

I knocked the bearings (bar one) and seals out today. The seals were like bakerlite and one of the crank bearings had a weird metal rim built into it???

I need to do some checking on that one as I know the 2 stroke lubes the big end. I also started to take out the cylinder studs, did 2 but one next one was solid, even with a stud extractor. I think I am going to put some heat and plusgas on the rest. Heat gun or blowtorch, what do you say? Also I have a couple of bolts to drill out so I can heat those too.

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I think I am going to put some heat and plusgas on the rest. Heat gun or blowtorch, what do you say?

Aye dirty" use a mixture of Acitone[ nail varnish remover] & ATF. , soak em in it, its 4 times better than WD40,, :rolleyes:

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Great stuff Blackhat, That rumble was moving all over the engine at the YOC weekend. I am glad you got it. That engine looks looooovly. Is it 40 years old now?

I knocked the bearings (bar one) and seals out today. The seals were like bakerlite and one of the crank bearings had a weird metal rim built into it???

I need to do some checking on that one as I know the 2 stroke lubes the big end. I also started to take out the cylinder studs, did 2 but one next one was solid, even with a stud extractor. I think I am going to put some heat and plusgas on the rest. Heat gun or blowtorch, what do you say? Also I have a couple of bolts to drill out so I can heat those too.

Fogive me if your well aware of this but put the heat on the case and keep the stud as cool as you can, (damp rags etc) if you heat the stud you run the risk of damaging the case.

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Aye dirty" use a mixture of Acitone[ nail varnish remover] & ATF. , soak em in it, its 4 times better than WD40,, :rolleyes:

That is supposed to be a lethal combination plus not good for the internal organs so I may leave that at one of the last options Blackhat.

Fogive me if your well aware of this but put the heat on the case and keep the stud as cool as you can, (damp rags etc) if you heat the stud you run the risk of damaging the case.

Cheers Cynic. I started a new thread on the heat thing and OG says about the same thing. Cheers.

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