crank stuffer

[stewart]

i  am building a crank stuffer for the kx500 i think the volume needs reduced  in crank case to increase the velocty of fuel charge in transfers  and riase crank case comprsion any input greatly appreciated stewart

[YUNGGUNNAZ]

i agree.especially if cylinder has drag port and cases have been matched with entrance rolled back.i have used devon epoxy for this before doing the bottom half way up with some shaping.can't wait to see what you come up with.check some of the moped or pocket bike sites.i think i saw something done there.

[KXcam22]

JB weld works nice. Machines cleanly to a smooth surface.  Isn't there a ratio between case and transfer port volume you try to shoot for?  I can't recall what it is anymore. Cam.

[doordie]

Good for flow BUT with higher pressure and the fresh charge maybe pushed
out `cause your high transferduration of approx 130 degrees,this at low rpm.
You can reduce transferduration to reduce that but you get a narrower powerband
though.
The aim of transfers must be reshaped to enter more at back of barrel to reduce
lost of charge.
You can try in small steps and see what?s happening,maybe KX500 have to low crankcase compression stock.

crankcase volume at TDC/crankcase volume at TDC - cylinder volume is the formula.

I think a expansion chamber with steeper cones will do the jobb better and still have 130 degrees of inlet duration left.

//doordie

[Friar-Tuck]

Stewart,
This is an old book however I believe the formulas are still applicable.
 This is a whopper of a pdf. 

http://www.edj.net/2stroke/jennings/2stroketunershandbook.pdf
 Best of luck,
Tuck \o/

[stewart]

great book thanks for posting it

[stewart]

whats expensive has one tongue  hauls 300 horses  and  covered in green ...  my bike  trailer

[maddoggy]

stewart, any progress on your crank stuffer idea? i have an idea that i think would accomplish this for you, however i don't want to post another of my hairbrained engine ideas on here so if youre interested "pm" me.   MADDOGGY

[stewart]

always interested to here any engine ides

[BDI]

Took four 1/8 by 3 foot rods to fill space, after machine work should lose one rod worth of material.This should easily make up for any material lost to port work and then some. also welded in main exhaust port but not ready to show pictures of that.I need to machine copper slugs to fill power valve cavity so I can weld in main exhaust port with out ruining cylinder.Looking to turn main exhaust port into upside down triangle and nock out bridges of of boost ports

[stewart]

that should decress crank case volume everything i have tried pionted to a  hp incress by decressing crank case volume

[BDI]

This mod should work fine with V-force reed because it does not need this space to fit like stock reed.

[stewart]

stewart, any progress on your crank stuffer idea? i have an idea that i think would accomplish this for you, however i don't want to post another of my hairbrained engine ideas on here so if youre interested "pm" me.   MADDOGGY

  ihope that every one on here is always glad to look at ides from hoever has them we all might learn somthing ,,  at least some idea  like bdi has just shown us means they are thinking and thats never a bad way to learn

[kaw rider]

stewart
from a stock motor on the dyno to your motors on the dyno how much are you increasing by.

[stewart]

20 hp