Stock cylinder specifications

[Pony]

I am starting to dick around with pipe design for my 500 project. I have some software (2 stroke wizard tuned pipe pro 3) that I am going to use for design and then my plan is to draw it up in CAD, print out a template and then get my welder buddy to give it a shot. Sooooo I started mapping out my cylinder and realized that I could very easily get some wrong numbers. While I am all about learning stuff I figured for the sake of a decent pipe and since some of ya'll might know this off the top of your head, I would be better off asking for some of ya'll knowledge

1984 CR500 Cylinder:

bore x stroke: 491x?

length x width of exhasut port

exhaust open period? degrees

main transfer open period? degrees

secondary transfer open period? degrees

rear boost open period? degrees

BTW I know this is kinda asking a lot but I will post the dimensions the software kicks out for ya'll to use/compare/ analyze ect. Thanks guys

[Roostius_Maximus]

I dont have it, but if you're clever you can call the guys at advance sleeve and ask them for specs on their part for that cylinder
that will give you somewhere to start from, go to torqsoft and enter the rod length and stroke, then the measurement from the top of the deck down to the port, gives you the location from inches as a degree.

I'm tired just having typed this

[Pony]

Well I appreciate you taking the time to type it out! Thanks for the info
I'll start calling around and see what I get! If all else fails I'll start taking measurements off my map and post up what I get.

[100hp honda]

I am starting to dick around with pipe design for my 500 project. I have some software (2 stroke wizard tuned pipe pro 3) that I am going to use for design and then my plan is to draw it up in CAD, print out a template and then get my welder buddy to give it a shot. Sooooo I started mapping out my cylinder and realized that I could very easily get some wrong numbers. While I am all about learning stuff I figured for the sake of a decent pipe and since some of ya'll might know this off the top of your head, I would be better off asking for some of ya'll knowledge

1984 CR500 Cylinder:

bore x stroke: 491x?

length x width of exhasut port

exhaust open period? degrees

main transfer open period? degrees

secondary transfer open period? degrees

rear boost open period? degrees

BTW I know this is kinda asking a lot but I will post the dimensions the software kicks out for ya'll to use/compare/ analyze ect. Thanks guys

all this stuff is easy to figure out. becomes much more complicated when doing areas and angles especially with hondas that have kickers in the ports. exactly what info does the program ask for ?

[Pony]

1984 CR500 Cylinder:

bore x stroke: 491x?

length x width of exhasut port

exhaust open period? degrees

main transfer open period? degrees

secondary transfer open period? degrees

rear boost open period? degrees

This is exactly what it asks for

[Roostius_Maximus]

did you completly miss what i'd said to do?
have you set the cylinder down on the cases yet? see if the piston comes flush to the top with a base gasket on it, measure down from the top in inches, use that software and you're done. Most of us would have finished this by now.

[Pony]

did you completly miss what i'd said to do?
have you set the cylinder down on the cases yet? see if the piston comes flush to the top with a base gasket on it, measure down from the top in inches, use that software and you're done. Most of us would have finished this by now.

No I didnt miss what you wrote. I went riding yesterday instead of shed time, plus I have a gasket kit on the way should be here by tomorrow. 100HP just asked exactly what the software wanted, and I was just saying that that is exactly what it wanted.

Once I get my gaskets in Ill do what you said. You will have to excuse my ignorance to some of this stuff, but I was not blowing off what you posted. Just havent had a chance to do it yet and was answering a seperate question.

[100hp honda]

theres a few things you need to do first. at what height do you plan to put the cylinder in relation to piston deck height ? some people lower it and some raise it. some leave it stock location. will you be altering the ports or leaving them stock ?

if you run stock ports and standard deck with .020 gasket then its easy to calculate heights. i prefer to bolt it together and use degree wheel but you could use a computer program to figure it out. if anything will be altered you have to figure that in. for exh width i use inside caliper and measure that with micrometer.

this might help. http://www.macdizzy.com/cyl_primer.htm

[Pony]

I measured to the top of the piston from the deck, got my measurements and came up with an exhaust port timing of 86.5 degrees ATDC via torqsoft. I read in a thread about a page back that (port timmings) that stock was close to 177.5 degrees. Was that not refering to ATDC? Once again, sorry for my ignorance just trying to get the correct information.

[Roostius_Maximus]

ok, i'm not certain on the '84, but if at bdc the piston sits level with the floor of the exhasut port (on some wet years it sits below or above) then you subtract the 86.5 atdc from 180, so 93.5 is the duration of the port being open on the powerstroke, for compression stroke is going to start obviously at 180 and close at 273.5, leaving you with 187 degrees of exhaust duration.

i've typed this between sever phone calls and talking to my shop guys if it dont make sense

if you think about it backwards the 177.5 degrees or whatever it was would mean the exh was open for 2.5, and on cyls with 188 degrees it'd never be open

dont fret, you'll figure it out