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1987 XL250R Rebirth

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Hello, I need some advice, and I am a novice, but a dedicated one.

I have a 1987 Honda XL250R that has been sitting for five years...I love this thing and I used to have so much fun on it, and I am determined to get it going again. I have the Honda Service Manual for this bike...

However my piston is seized. (I know it’s a bad thing)

I have been putting penetrating oil in the spark plug hole but to no avail.

Now trying to get to the cylinder and piston to check em out.

Took Cylinder head Cover off, but could not rotate engine to get TDC...I hope I didn't kill it already.

Problem now is cam chain won't move to get to the bolts to take off Cylinder Head...In the book its says lift the cam chain tensioner up, but it’s stuck down in there… I’d hate to cut cam chain

[Any suggestions would be greatly appreciated...

Edited by Cactus777

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Cactus , have you undone the camchain tensioner ? If so you should be able to lift the chain off of the camchain sprocket and then take out the cam . You wont need to worry about having the motor at TDC for stripping down , but you will when assembling , greg

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Thanks for replying Greg..

Your absolutly right I should have done that, unfortunately I pushed a pin out on my cam chain and released it that way.

I have my cylinder head off, and the piston is siezed at the top (picture included)

Putting PB Blaster, Liquid wrench on th piston for the last several days....Samcked it a couple of times (but not too hard) piston did not move...

A mechanic told me that he could "easily" unstick the piston, for a price....But I have never heard of anyone so confident...I have no extra money to put in the bike...So I think he's ploying me.

Question: Should I heat the piston with a torch kit from home depot? If so how long...Then what?

Question: I can't get my bike back into nuetral... So how do I and what do I turn to try and move the piston...

Today I am planning on removing the engine and the right crankcase to see whats going on inside...

Any suggestions....Thanks....

034.JPG

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Hi Cactus:

just some thoughts:

Almost every time a 4 stroke engine is shut off it stops on the compression stroke and sometimes, like yours, right at the top.

You might be able to get back to neutral by raising the rear wheel and rocking the transmission with the wheel as you shift. If you can't get it, leave it as is, there is enough free-play to allow the piston to start to move even in gear if the wheel is up.

I wouldn't try smacking the piston, your piston is at TDC which is not good. Any smacking will just hammer the connecting rod directly down to the bearings. I would build up a dam of putty or sealant around the piston and try to keep it filled with penetrating oil. Building up a "head" of lubricant over the piston will force more penetrating oil into the cylinder. Heating a big mass like a cylinder with air-cooling fins might do more harm than good.

Turning the crankshaft is your only real option if you want to save the bearings. Let it soak and try turning the alternator rotor back a forth now and then, or get a wrench on the crankshaft somehow. Give it lots of time. Don't use heavy force or a breaker-bar just keep trying it and letting it soak, and trying again until you get just a few thou of motion indicating the piston is free then keep twisting it back and forth until the rings loosen up too. The mechanic was probably thinking of using an impact wrench on the crankshaft which might work after a good soak but only if it was done very gently.

If you can find an old alternator rotor to install it would give you something to yank and tap on. Avoid hammering on the crankshaft gear (clutch side). The worst case is you have to chisel the piston out but then for sure you will be splitting the cases to clean the junk out of the crankcase. If you can avoid getting frustrated, it will move, eventually, and you might be able to save the effort of a complete tear down because the lower end is probably fine.

patuca

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Thanks Patuca,

I pulled the engine and leveled it on a work bench. I have a little puddle on top of the piston but not much, but better than before...

I was thinking about heating the piston not the cylinder, but I like your ideas, just need patience...

One time I read somebody used dry ice on their piston and shrunk it and it moved....

Using pb blaster and liquid wrench...

Looking to get some kroil locally....Thinking about the acetone and atf.

Patience is a virtue.....

I'll probably pull the crankcase to get to the crankshaft...

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OK..

I want to remove the oil pump...

Have the original manual...

Removed bolts, and everything else I have too...Its stuck how do I remove it???

006.JPG

Engine is still siezed,

Here is my resevior. I bought some KROIL and filled resevior.. Letting it soak...

011.JPG

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