Engine Trouble Crankshaft won't spin

[crassius]

Im having the same problem i replaced the cylinder but when i torque the head down the motor wont turn in a certain spot i think the piston is hitting the head. Can i run double head gaskets or do i need another cylinder.

could be that you have a 40mm stroke which often uses two base gaskets to get clearance at the top - undo head and hold it down with your hand while turning motor - you should be able to tell if one extra gasket will fix it (note: base gaskets come as either thick or thin & 40mm needs two thick ones)

 

[gary55]

What you have is a 38mm stroke engine with a new piston for a 40mm stroke. Your new type B cylinder will mic. out to about 2.740. The type A cyl. will mic. at 2.778. So a extra head gasket with a type A stroke piston and engine, and a type B cylinder will raise you a extra .027 giving you 2.767. The head is not in question so much as the hight of your new cylinder. Your compression will be pushing the limit with a slant plug head at about 145 lbs.. In short you can get away with just a type a piston, and a type b cylinder with two head gaskets, but for no more than it costs I would get the proper cylinder and piston. I looked around at the ebay ads, and most of them have their facts ass backwards. Contact the supplier you chose and tell them you need a top end that has the piston with the lower hole.

 

[boss4457]

ok thanks a lot i have some gaskets on the way i will let you know how it goes

 

[gary55]

You will still need the type A piston with the lower hole. No amount of gaskets top or bottom will change the pistons clearance issue to the crank wheels. The key word is the lower hole as some vendors are labeling them wrong, but higher and lower are terms that even they should be able to grasp. I wish you had some pics. of the old and new pistons and cylinders side by side. If you set the cylinders upside down on a flat surface and put a straight edge across the bottom of them you can see if one is taller than the other. Pictures can help us help you more accurately, and possibly keep you from ordering parts incorrectly. Good luck I'll be interested in the results.