Bigbill
Husqvarna
Pro Class
Ok I have a last production 390cr cylinder. I'd like to use it on a 430cr bottom end.
The problem is the 390=71mm stroke while the 430=74mm stroke. So that's a 3mm stroke increase. Technically it's a 1.5mm increase at the top and 1.5mm increase at the bottom. So installing two base gaskets should work. I might need a thin spacer. What glue would you use to stick the base gaskets together?
The older pre '82 390 cylinder has about 3/4 in size of the transfer ports when compared to the newer post 82 cases. There's room to match the 390 smaller transfer ports to the larger transfer ports in the newer case.
Does anyone polish the inside of the crankcase for easy flow?
I seen a engine builder do this on a husqvarna chainsaws for better smoother flow. Is there any info on doing any porting on the lower cases? I'm thinking of building one animal hairy ride not for the faint hearted.
Just a future thought. I have three big bore cases and two bikes. I have an addiction of going on a binge building engines. Then I restore one bike at a time.
I'm a sick man.
The problem is the 390=71mm stroke while the 430=74mm stroke. So that's a 3mm stroke increase. Technically it's a 1.5mm increase at the top and 1.5mm increase at the bottom. So installing two base gaskets should work. I might need a thin spacer. What glue would you use to stick the base gaskets together?
The older pre '82 390 cylinder has about 3/4 in size of the transfer ports when compared to the newer post 82 cases. There's room to match the 390 smaller transfer ports to the larger transfer ports in the newer case.
Does anyone polish the inside of the crankcase for easy flow?
I seen a engine builder do this on a husqvarna chainsaws for better smoother flow. Is there any info on doing any porting on the lower cases? I'm thinking of building one animal hairy ride not for the faint hearted.
Just a future thought. I have three big bore cases and two bikes. I have an addiction of going on a binge building engines. Then I restore one bike at a time.
I'm a sick man.