Why stacked base gaskets?

[Will'smotobikes19]

Does anyone know why they do this crap? stack base gaskets and not use some type of sealer in between? I think this is where my running issues are coming from. I can see a gap at the base of the cylinder.

 

[Spare_Parts]

It is because the cylinder is for a slightly smaller stroke. Think there is 3 heights for the cylinders, definitely 2. Take a picture and post it. May not be an air gap.

Look, I gave you a normal answer because you asked a normal question. That's all it takes.

P.S. can someone tell him to read this?

 

[JerboaJohn]

Spare said "It is because the cylinder is for a slightly smaller stroke. Think there is 3 heights for the cylinders, definitely 2. Take a picture and post it. May not be an air gap.
Look, I gave you a normal answer because you asked a normal question. That's all it takes."
^ lolz,,
personally I would do it for 2 reasons. piston too high up bcs maybe cylinder milled too much or just is short or you can experiment with altered port timing

 

[Will'smotobikes19]

When I took the jug off the top gasket ripped in half. I took 2 sides of a card box (briggs and stratton starter cord) and put max oil resistance gasket maker in between. Going to torque the head tomorrow and see if it fixed anything.

 

[gary55]

Does anyone know why they do this crap? stack base gaskets and not use some type of sealer in between? I think this is where my running issues are coming from. I can see a gap at the base of the cylinder.

You can stack base gaskets without sealer and it will work. I've done it. Nothing wrong with using sealer if it gives you better peace of mind. If you have torqued the head nuts and you are still seeing a gap at the bottom of the jug the nuts are bottoming out before they tighten the head. Use washers to correct this.

 

[gary55]

Another thing if your talking about a Zeda/ CDH engine They stack the base gaskets because with the stock head the clearance is to small at the head to piston spacing. If your using a aftermarket head with one of these engines and a .7mm copper head gasket it gets real close to the sweet spot. Since I don't really know what your working with everything is a shot in the dark so if you could provide more Info it will help us in possibly solving your problem.

 

[Will'smotobikes19]

Its a pk80 from Umoto

 

[gary55]

Its a pk80 from Umoto

Well I'm not sure if I'm going to be any good because I've never had one of those engines. Meaning that I don't know who Umoto uses for a engine supplier. The prob. is that the PK80 nomenclature has been bastardised. The originals were A type piston short rod long stroke engines with a 2.79" jug, and now some of the new ones that are labeled PK80 are basically the same as a Zeda engine with a B type piston long rod long stroke, and a 2.44" jug. Still if you have a gap at the base the head is not getting tightened. You really should try to give us some pics. if you can.

 

[Will'smotobikes19]

Still if you have a gap at the base the head is not getting tightened.

17ft lbs it’s 40mm stroke by gap I mean not seeing through just seeing the space between it.

 

[Will'smotobikes19]

I’m just trying to find out why throttle is delayed