So!! Ive started the work on my newest trials bike! Im really excited. I have only a small amount of background on this bike. The previous owner told me that he used it regularly up untill a couple years ago. He told me that when he tried to start it after it was sitting for more than a year, he found it had siezed. Its VERY damp up here in B.C. Canada so I assumed rust. I removed the cylinder head, and sure enough, it was rusted all over the walls. I looked through the exhaust port and the piston is also rusted.

Now, I cant seem to free them from one another. Does anyone have any tips on breaking the seal?? Ive loaded it with WD-40 and still no luck. I'll leave the WD-40 untill tomorrow and see if that helps. If not, any ideas??

Here are a few pics of the rusted cylinder. Before AND after the WD-40

heat...lots of it on the clyinder nad then a BIG wooden mallet. The crank will be buggered anyways so off you go...

L

heat...lots of it on the clyinder nad then a BIG wooden mallet. The crank will be buggered anyways so off you go...

L

Shouldn't the crank be just fine it if siezed while sitting? What could have happened to it?

Coca Cola

Heat and a big hammer are , unfortunately, the way to get it apart. You will need a rebore and new piston and rings. The crank might be OK. You can see when you get there.

Edited January 4, 200917 yr by Andy
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Did anyone mention patience?

You can't let it sit long enough with WD-40 (although I prefer Liquid Wrench).

Heat and a big hammer are , unfortunately, the way to get it apart. You will need a rebore and new piston and rings. The crank might be OK. You can see when you get there.

That will reguire re-jetting of the carb. . . will it not?

That will reguire re-jetting of the carb. . . will it not?

Depends on how hard you hit the carb with the hammer.

just fill the thing with diesel and let it sit for a couple of days. yeh you will need a new piston and rings and a rebore but a carb clean up (inside) should be ok. might take a while but it shouldnt be expensive all in and the thing will be bullet proof when done..

You should be able to pound the piston down with a piece of 2x2 and a big hammer. That barrell looks pretty badly rusted and with the transfer ports open I'd be surprised if the crank bearings aren't rusty too. When you're ready to bore the cylinder let me know, I'll give you the number of the best guy for the job.

You should be able to pound the piston down with a piece of 2x2 and a big hammer. That barrell looks pretty badly rusted and with the transfer ports open I'd be surprised if the crank bearings aren't rusty too. When you're ready to bore the cylinder let me know, I'll give you the number of the best guy for the job.

Definetly will do that! Im hoping it wont be too long from now!

Let the wd-40 and oil soak for a couple of days, and then the block of wood and hammer, when you get it moving you can pull the barrel up and chock it with a bit of wood each side and then hit it down again.

It might take a few goes to get the barrel right off the piston.

I'd check the crank mains when its apart incase the rust got to them, i hate a dry sounding motor!!

Edited January 5, 200917 yr by hop blip and a jump

Further to MartinF's Coke idea:

For a while my Dad was restoring vintage tractors in NZ. His first, a Farmall F12, was seized solid after sitting for decades under a Macracapa tree (the vertical exhaust having filled the engine with water). a couple of 2 liter bottles of Coke down the barrel, wait a week, then tow it down the road dumping the clutch in top gear. Hey presto! it freed. Years later it still runs like a dream I don't think he has ever even lifted the head of it to check the condition.

Mind you it didn't have transfer ports, and it is a tractor..Err maybe just heat it and hit it as others have suggested.

Cheers and good luck