REVIVING A DORMANT ENGINE !!

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tat ty
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REVIVING A DORMANT ENGINE !!

Postby tat ty » Sun Feb 12, 2012 6:08 pm

I have a recently aquired TY250A which I will in due course set about restoring.

The bike does not appear to have had a hard life and I suspect that it has been used as a trail bike.

I think that it probably has lay dormant for quite a long time, (anyones guess) but it does have spark and good compression.

One of the things that I wish to do is start the engine to check whether it needs a total rebuild, or whether I can get away with less than that.

The question that I want to put out there is this .........

What should I do to ensure that, upon starting, I don't do any damage to bearing surfaces and the like, beyond what may exist now !

I imagine things are probably pretty dry in there.

Plenty of time up my sleeve on this one and plenty will be needed, so I simply don't want to create more work than already exists.

Any suggestions willingly taken on board !

Alastair Farquhar

0409 603 880



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Re: REVIVING A DORMANT ENGINE !!

Postby David Lahey » Sun Feb 12, 2012 7:42 pm

If the big end or mains have any rust damage, there is nothing you can do at this point to prevent them collapsing soon after it is first started, no matter what you do before you start it up.
To minimise damage due to starting dry, squirt some aerosol pack spray oil into the big end by taking the reed cage out and putting the piston at the top. Then squirt some into the little end bearing through the piston windows, and then leave it lying on one side then the other to wet the mains. Once it is back upright again, lift up the front of the bike to get the piston top horizontal and squirt some some down the sparkplug hole for the rings. After it has soaked for a while, rotate the motor slowly and feel for problems.
Even if everything goes well and frees up and then runs normally, get ready to stop the motor very quickly if it starts making odd noises, to minimise damage from failed bearings sending metal particles through the motor.
I was out riding with a friend today who was on an unrestored TY250A that had not been ridden for donkeys years until he got it a year or so ago. It had had a few rides and ran and still sounded OK but today the LH main bearing collapsed. We didn't know the bearing had collapsed at first, it just stopped firing while being ridden along at a steady speed. Upon taking the mag cover off to check the points, it was quite obvious why it had lost spark - the flywheel has massive up and down movement due to the collapsed main bearing.


relax, nothing is under control

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Re: REVIVING A DORMANT ENGINE !!

Postby Guy53 » Mon Feb 13, 2012 2:17 am

To had to David's post, if the bikes has been sitting for a looong ... time the crankshaft seal could be quite dry and could be a source of baaaad thing.

Guy



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Re: REVIVING A DORMANT ENGINE !!

Postby pop » Mon Feb 13, 2012 9:48 am

I think I would purpously flood the engine[kicking it over like a 1980s Italjet owner]with the choke and throttle wide open and fill and drain the carby few times then take the plug out and deflood it. :shock:



tat ty
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Re: REVIVING A DORMANT ENGINE !!

Postby tat ty » Mon Feb 13, 2012 5:31 pm

Thanks David and others.

I had considered filling the crankcase with Diesel in order to get some lubrication in to the main bearings.

Fill it and leave it for a few weeks prior to draining.

Wonder whether that will damage the main seals?

Alastair.



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Re: REVIVING A DORMANT ENGINE !!

Postby David Lahey » Mon Feb 13, 2012 6:08 pm

Filling it with premix or diesel might be a good way of knowing if the seals are going to seal or not. If you are worried about diesel wrecking the seals then use premix to fill it with.
I probably wouldn't put diesel in it because there will be a residue which will make it stink when it is started


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pop
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Re: REVIVING A DORMANT ENGINE !!

Postby pop » Mon Feb 13, 2012 6:22 pm

How would you get all the diesel out????dont kick it over with too much fuel in the bottom, a bit like passing a 4" wide stool thru 1" passage, could even bend a rod or blow the seals .



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Re: REVIVING A DORMANT ENGINE !!

Postby David Lahey » Mon Feb 13, 2012 7:34 pm

You could turn it upside down and let it run through the transfer ports and out the spark plug hole, same technique as for bulk dewatering of a motor. Also need to lean it to one one side to get the last bit of fluid out that would otherwise stay up inside the piston if you left it upside down. For Yamahas and also other bikes with a transfer port at the rear it can be balanced on the rear wheel for this bit if it is easier to do it that way.


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Re: REVIVING A DORMANT ENGINE !!

Postby Jon V8 » Mon Feb 13, 2012 8:02 pm

I think filling the motor with anything is just going too far,Davids original suggestion of spraying oil into the big end etc is all you need to do - nothing more.
You will soon find out then if its any good,or if like my main bike that the crank pin was rusty when I first bought it.If its OK you have won,if its shot you can then rebuild it knowing you will get many further years of use from it.



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Re: REVIVING A DORMANT ENGINE !!

Postby Tioli » Sat Feb 18, 2012 8:22 pm

I like David’s reply plus I would take the flywheel off and clean and that is clean with out pushing in dirt into the seal. Really clean the hole area around the seal with the stater plate removed. Leave a film of oil on the seal then check it later for any leaking. About all you can do for the other one is replace the oil. I don’t think there would be any way of splashing some up there with out starting the motor.
If the seals go you will get a lean out and seize the motor or at lease nip it up.


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