KX Riders
Maintenance & Technical => KX500 Original => Topic started by: stewart on April 17, 2007, 01:46:13 PM
-
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
-
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.
-
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.
-
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. :wink:
//doordie
-
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/
-
great book thanks for posting it
-
whats expensive has one tongue hauls 300 horses and covered in green ... my bike trailer
-
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
-
always interested to here any engine ides
-
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
-
that should decress crank case volume everything i have tried pionted to a hp incress by decressing crank case volume
-
This mod should work fine with V-force reed because it does not need this space to fit like stock reed.
-
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
-
stewart
from a stock motor on the dyno to your motors on the dyno how much are you increasing by.
-
20 hp
-
look at these crank stuffers
http://www.ozebook.com/compendium/t500_files/grant/imagepages/image34.htm (http://www.ozebook.com/compendium/t500_files/grant/imagepages/image34.htm)
-
great pictures
-
stewart, sorry for the late reply. i did some looking at the crank stuffer idea i had and i decided that the idea i had will not work. however i was wondering if it would be possible to extend the tabs on the bottom of the cylinder slightly. 1/4" worth of extention would help in a similar way as BDI's latest intake mod. by the way, good thinking there Brian, do you plan to fill a little more? MADDOGGY
-
Just to let you know the cylinder I'm welding on is junk I try out my ideas on it and there is no stress. I have a good grasp on two stroke design but applying my ideas can bee tricky so I do it to that cylinder for the practic of doing it. what I have done could easily bee done and probably done better with some sort of epoxy like JB Weld or my favorite marine tex. If you did this and you are using a V-force you will have to clearance for the petal screws but thats it. I don't think you can go wrong with this. You can over stuff a motor but you would have to work real hard to achieve it.
-
i have some ratio number for big single 2 smoke motor. do anybody have the ccr numbers.
-
i have some ratio number for big single 2 smoke motor. do anybody have the ccr numbers.
I think you are just going to have to cc the bottom end yourself. Do you really want to depend on what someone else says?. :|
-
i'm not to the stage of the dyno testing yet. working on different things now. but i will when i get there. i did find one error in cylinder. it short cycle the ports.
-
i'm not to the stage of the dyno testing yet. working on different things now. but i will when i get there. i did find one error in cylinder. it short cycle the ports.
If your talking about the fact that the piston does not go down far enough to uncover the transfer ports Your right on the money. This is good for a few horse power when corrected and there is a couple of ways to do it and there is some numbers to correct it by but I'm not sure if I want to go blurting them out.
-
that's not the one that i found. what would happen if the piston shirt didn't cover the exhaust port at tdc.
-
If your piston skirt does not cover the exhaust port at tdc then someone has lowered the floor of your exhaust port to meet the top of the piston at bdc. This would normally be a performance mod on a two stroke motor. On the KX500 the piston skirt is not long enough to cover the port at tdc. This is bad. It's going to allow the return wave from the pipe to shove exhaust underneath the piston and foul the intake charge with exhaust gasses. I have thought about contacting Wiseco about having pistons made with a longer skirt but it would be more work than it would be worth unless I was going to have a bunch of pistons made.
-
bdi
the aux exhaust ports short cycle. but that wouldn't be a problem intill kips open up. look at the picture i posted with the kips drum. what looks different with it.
-
Well you successfuly got me confused. If your talking about the fact that the kips drums dont uncover the secondary exhaust ports completely thats a easy fix just a little grinding fixes that. I dont get what you mean by short cycle.
-
can somebody post a picture of a oem cast piston.
-
I have ben in the shop playing with a piston and cylinder to try and figure out what you are talking about. If you are talking about the cut out on the side of the piston causing the secondary exhauste port and the forward transfer port to overlap I think that is one of those two stroke things that you can't do anything about. :|
-
yes you did find it. yes there is a fix. weld up both port around 1.5mm narrower. i do that done when have many other things welded on the cylinder at the same time. i done it on my current cylinder.
-
Just to let you know the cylinder I'm welding on is junk I try out my ideas on it and there is no stress. I have a good grasp on two stroke design but applying my ideas can bee tricky so I do it to that cylinder for the practic of doing it. what I have done could easily bee done and probably done better with some sort of epoxy like JB Weld or my favorite marine tex. If you did this and you are using a V-force you will have to clearance for the petal screws but thats it. I don't think you can go wrong with this. You can over stuff a motor but you would have to work real hard to achieve it.
Vforce 3 doesn?t have any pedalscrews.... :wink:
-
yes you did find it. yes there is a fix. weld up both port around 1.5mm narrower. i do that done when have many other things welded on the cylinder at the same time. i done it on my current cylinder.
Less portarea or less shortcircuing,kolera or pest? :|
I would use JB-weld and try that before welding..... :wink:
(easy to remove)
Here is a portmap,draw/paint how do you mean kawrider. :|
-
If your piston skirt does not cover the exhaust port at tdc then someone has lowered the floor of your exhaust port to meet the top of the piston at bdc. This would normally be a performance mod on a two stroke motor. On the KX500 the piston skirt is not long enough to cover the port at tdc. This is bad. It's going to allow the return wave from the pipe to shove exhaust underneath the piston and foul the intake charge with exhaust gasses. I have thought about contacting Wiseco about having pistons made with a longer skirt but it would be more work than it would be worth unless I was going to have a bunch of pistons made.
IF you raise barell and shave of top of barell,you have a win/win situation.
No more uncovered exhaust at TDC and raised portduration for more power/RPM at the same time..... :wink:
(You can also deepgrove cylinderhead and not shave barell at top)
-
This is a easy mod to raise ccr... :-D
-
This is a easy mod to raise ccr... :-D
Hey doordie those are ceramic main bearings aren't they? very nice 8-)
-
If your piston skirt does not cover the exhaust port at tdc then someone has lowered the floor of your exhaust port to meet the top of the piston at bdc. This would normally be a performance mod on a two stroke motor. On the KX500 the piston skirt is not long enough to cover the port at tdc. This is bad. It's going to allow the return wave from the pipe to shove exhaust underneath the piston and foul the intake charge with exhaust gasses. I have thought about contacting Wiseco about having pistons made with a longer skirt but it would be more work than it would be worth unless I was going to have a bunch of pistons made.
IF you raise barell and shave of top of barell,you have a win/win situation.
No more uncovered exhaust at TDC and raised portduration for more power/RPM at the same time..... :wink:
(You can also deepgrove cylinderhead and not shave barell at top)
I think a good number to raise the cylinder by is .040 you could accomplish the same thing by stroking the crank to 88mm that way the piston goes down 1mm further. I'm alll about stroking it :-D
-
stewart, have you dyno'd an engine with a reed spacer installed? i'm just wondering if the spacer does indeed lower your horsepower a little just opposite of the crank stuffer. i would think it would but just looking for your dyno say so. MADDOGGY
-
i was thinking about your reed area mod bdi. you could place some soft (modeling)oil clay in the side area and then push in a v-force, take it back out and shave for clearence. VOILA, maximum intake crank stuffage. take measurements and install marine epoxy to same measurments. what do you think? MADDOGGY
oh by the way, that is one sweet picture!
-
i do not think kawisaki missed this fact that the last exh booster port to open,, the two outside ones had the highest duration for top end and it bieng directly above the intake transfer port with some short circuting happing at high rpm my help draw the charge in to cylinder case......ps reed spacers make less power but that can make the bike hook up better and thus seem faster or more ridable so theres a place for every mod..
-
i was thinking about your reed area mod bdi. you could place some soft (modeling)oil clay in the side area and then push in a v-force, take it back out and shave for clearence. VOILA, maximum intake crank stuffage. take measurements and install marine epoxy to same measurments. what do you think? MADDOGGY
oh by the way, that is one sweet picture!
I have thought of doing something very similar. I was thinking of making a mold and casting some stuffers out of liquid rubber. I think it would work good because the reed would hold them in place and you could take it out if you didnt like what it did. It would be the antispacer. :evil:
Thanks on the picture that is a actual picture taken on my work bench holding a torch in one hand and the digital in the other. That skull and cross bones Is a BDI original I got the copy right from the us copy right office not to long ago. I have stickers cut out of vinyl allready and I plan to have some beanies made up among other things.
-
removable stuffer------ i like that idea alot, that's good stuff bdi. :evil: MADDOGGY
-
stewart
you are correct. my dyno test showed a improvement on bottum end when ports were narrowed. but i'm running a different exhaust port set up. it did make a small hp differnet up top too. 1.5hp, to small for the cost to proform mod. i think 80hp at the rear wheel will be seen this year.
-
that cylinder has .020 cut off the base. it had that done to it along with alot of kips mods. i did that this summer. and know i have another cylinder with a different exhaust ports set up. i think by mid summer i will have the cylinder were i want it. this cylinder kips have more travel then the stock kips do. toke some time but worth it.
-
Why did you take .020 off the base?
-
it looks like BDI likes to play with fire. nice pic. is this off topic?
-
it looks like BDI likes to play with fire. nice pic. is this off topic?
I bet that 90% of the people on this site have burned something down on purpose at some point in their life, I know I have :evil: For me it goes blow stuff up,burn things down and ride my kx500
-
I bet that 90% of the people on this site have burned something down on purpose at some point in their life, I know I have For me it goes blow stuff up,burn things down and ride my kx500
for me its burn then ride and blow stuff up. yea i like to burn before i ride
-
stewart, in the mid to late 80's Kawi had three motors designed to short circuit, another words exhaust side cutaways to allow raw fuel to exit cooling the exhaust side of the piston.
The motor lost bottom end, but 80% of that was recovered with electronics and timing curves.
The reason they did the short circuit was to reduce temp in the exhaust side of the piston.
The tecate had the biggest problem passing endurance testing and that was the post production cure.
I have talked to alot of people over the yrs, very few that have noticed the design flaw.
-
stewart, in the mid to late 80's Kawi had three motors designed to short circuit, another words exhaust side cutaways to allow raw fuel to exit cooling the exhaust side of the piston.
The motor lost bottom end, but 80% of that was recovered with electronics and timing curves.
The reason they did the short circuit was to reduce temp in the exhaust side of the piston.
The tecate had the biggest problem passing endurance testing and that was the post production cure.
I have talked to alot of people over the yrs, very few that have noticed the design flaw.
Thats all great but I still want to know why you cut.020 off the base and why did you take that cool picture off that showed the exhaust mod that I have been talking about doing for some time? And who did the mod it looks like they did a very good job of it?
-
i thought the reason was to allow more complete filling of crank case by creating a draw at farthest piont from reeds,,,,i have been looking at a number of ways to accomplish this maybe better maybe not ...i feel if i can create a presure drop frathest from reed tip simmiler to venting a gas tank fill tube or filling any area faster i can create a super charge affect on my crank case compression ,,
-
Bdi
i had stewart cut the base. he has the tooling for it. that cylinder was .004 warp. set up for zero deck height. plus tighten up CCR. i did all the exhaust mods and porting, to much time to do for a paying customer. plus there other mods to intake side and alot of exhaust tunnel work. i what to have great buttom end with this set up. 158* closed exhaust to 192*exhaust open kips. stock kips around 165-168* to 182-185*exhaust. i'm up here in sled country and guys have custom cylinder that are 12 port. the kx 500 motor was designed around a bike frame and made for 4,000-6,000 rpm. i'm working on a cylinder now that will have alot of welding done to it.
-
Not trying to get into an arguement over the subject, but as of that time nobody had ever questioned the large side mills on the pistons to the people that we delt with at Wiseco. I was told by "someone who should have known" that the Kawasiki guys didn't realize it at the time either. Once it was brought to their attention I am sure there could have been several reasons for it.....the pipe thing sounds as good as any I have heard, and better than I could have came up with....lol
Like I said, I am sure we didn't discover anything that other builders hadn't already noticed......maybe we just didn't keep our secrets as well as some others did
I have seen the same type of problem with a couple of the Snowmobile engines, (even seen one that opened their hook exhaust ports straight into the crankcase at TDC, with the cutaway under the wristpin), it seems to happen more in the first year or two that they would start using the auxilary exhaust ports.....and then they seem to change the designs.....
-
The only thing I wonder is why people that want more bottom end dont just make the main exhaust port smaller I'm allways talking about the upside down triangle and there is good reasons that works real good for making good bottom end and you dont really have to make the port a lot smaller Its more or less the shape but thats more then I feal like typing about right now. Happy new year
-
Playing with mspaint.....
1.Modified portshape and more portarea.
2.Modified portshape to avoid shortcircuing but need refilling with JB-weld and with little less portarea.
3.More portarea with lowered exhaust floor.
1+2+3=maybe more power without shortcircuing! 8-)
(Mike Melde have a similair portmap)
I have a barrel with sleeve and can test this mods later.
-
This is a easy mod to raise ccr... :-D
Hey doordie those are ceramic main bearings aren't they? very nice 8-)
Yes,but isn?t a KX500 engine.... :wink:
BUT soon will my engines runs with this hybrid ceramic bearings.....and a composit
rod from a Swedish company www.mxcomposites.com
Ceramicbearings from a another Swedish company www.vasatech.se
-
This is a easy mod to raise ccr... :-D
Hey doordie those are ceramic main bearings aren't they? very nice 8-)
Yes,but isn?t a KX500 engine.... :wink:
BUT soon will my engines runs with this hybrid ceramic bearings.....and a composit
rod from a Swedish company www.mxcomposites.com
Ceramicbearings from a another Swedish company www.vasatech.se
-
With the big square exhaust port as the piston travels down and the port opens exhaust gas velocity slows down. With the upside down triangle the exhaust gas velocity stays high as the piston goes down, do to the port narrowing. From what I have read if the port is designed right with the proper taper the upside down triangle port will flow as much as a larger square port and lend to better filling of the cylinder do to the fact that gas velocity stays high longer. This is stuff I have learned from playing with nitro rc cars. The nitro rc car engines that use this technoligy flat kill the ones with the old style square port. If you were to take both engines apart and try to decide which one was going to perform the best based on looking at the ports your knee jerk reaction would be to pick the one with the great big square port. When you take your car out and run it the one with the big square port gets sadly out performed by by the engine with the upside down triangle port.Your rc car goes from fast with the old style exhaust to retarded fast and pulling power wheelies with insane top end with the triangle port.
-
for me its burn then ride and blow stuff up. yea i like to burn before i ride
[/quote]
me too ! 8-) :wink:
-
bdi, lets see if i understand your upside down triangle thoughts correctly. the narrow section of the taper will increase the exhaust pipe pressure much like an orfice increases pressure in a hydraulic system. is my understanding correct? i'm not doubting you but if this is how it works i'm still unsure of the benefits. with hydraulic orfices the pressure is increased past the orfice but the volume of oil passing through is reduced. the same would happen with the exhaust flow if i'm thinking right. just doing some out of the box thinking here. MADDOGGY
-
I guess a upside down triangle is a bad description It is a trapezoid. The idea is to have the left and right port walls get slightly closer together towards the bottom. when the piston first starts to uncover the port the gasses are under high pressure so it comes out fast but as more and more of the port is uncoverd the pressure drops and the gasses slow down. the idea is if the port narrows towards the bottom the gasses keep moving fast even though the pressure is droping.It's like when the river is wide the water flows slow but when the river narrows the water moves faster. Yes I'm sure the port has to flow less but this should make great bottom end torque and mid range. I want to make up for this with larger secondary exhaust ports but I do not think this would have that great of an impact on top end because we are not talking about making the port a lot smaller and by the time the port opens all the way It has allready done the vast majority of its flowing.
-
Aren't those conrods just for 4 strokes?
Shouldn't exhaust ports be flat on the top to make sudden pulse.
-
I guess a upside down triangle is a bad description It is a trapezoid. The idea is to have the left and right port walls get slightly closer together towards the bottom. when the piston first starts to uncover the port the gasses are under high pressure so it comes out fast but as more and more of the port is uncoverd the pressure drops and the gasses slow down. the idea is if the port narrows towards the bottom the gasses keep moving fast even though the pressure is droping.It's like when the river is wide the water flows slow but when the river narrows the water moves faster. Yes I'm sure the port has to flow less but this should make great bottom end torque and mid range. I want to make up for this with larger secondary exhaust ports but I do not think this would have that great of an impact on top end because we are not talking about making the port a lot smaller and by the time the port opens all the way It has allready done the vast majority of its flowing.
BDI is this close to what your talking about. the top would be stock and the bottom a BDI mod.
(http://65.57.254.60/ktmtalk/photogallery/galleries/Parts_Mods/jpeg.JPG)
-
I guess a upside down triangle is a bad description It is a trapezoid. The idea is to have the left and right port walls get slightly closer together towards the bottom. when the piston first starts to uncover the port the gasses are under high pressure so it comes out fast but as more and more of the port is uncoverd the pressure drops and the gasses slow down. the idea is if the port narrows towards the bottom the gasses keep moving fast even though the pressure is droping.It's like when the river is wide the water flows slow but when the river narrows the water moves faster. Yes I'm sure the port has to flow less but this should make great bottom end torque and mid range. I want to make up for this with larger secondary exhaust ports but I do not think this would have that great of an impact on top end because we are not talking about making the port a lot smaller and by the time the port opens all the way It has allready done the vast majority of its flowing.
BDI is this close to what your talking about. the top would be stock and the bottom a BDI mod.
(http://65.57.254.60/ktmtalk/photogallery/galleries/Parts_Mods/jpeg.JPG)
Yep just like that.
-
brian, that makes good sense to me. i think you're on to something here. it could work, when are you going to try it? MADDOGGY
-
As soon as I can find a good cylinder to build the way I want. It will probably be a while though because I want to build a stroker crank too and the cylinder will have to be built to suit the stroked crank.
-
bdi
who's going to do the crank for you.
-
Aren't those conrods just for 4 strokes?
You can order for anykind of bike(2t or 4t),just measure and let them fabricate one. :wink:
Just 1000$ :-D
-
You know looking at the size of the rod It is going to displace more air in the bottom end and drive up the primary C.R.
-
check out this saw.
-
check out this saw.
What kind of horse power is it putting down at the chain :lol: :lol: :lol: :lol:
-
this cylinder kips have more travel then the stock kips do. toke some time but worth it.
How did you do that? :-o
-
doordie
i'm running 162* to 192* with kips. takes alot of time to do. i have about 15 hours in invested, but the next one i do i can do in about 7 hours. stewart cut .020 off base.
great pull from 4500 to the moon. i think stock 168* to 182* exhaust timing.
BDI
he has seen my exhaust port set up. i'm working on some other great cylinder set ups. these engines when design made for 3500-6000 rpm range.
-
doordie
i'm running 162* to 192* with kips. takes alot of time to do. i have about 15 hours in invested, but the next one i do i can do in about 7 hours. stewart cut .020 off base.
great pull from 4500 to the moon. i think stock 168* to 182* exhaust timing.
BDI
he has seen my exhaust port set up. i'm working on some other great cylinder set ups. these engines when design made for 3500-6000 rpm range.
You,BDI,Steward and some others are serious tuners at this forum,glad to be a part of this mission to make K5 to a greater bike! 8-)
-
bearings
-
kaw rider
are the balls (in your bearing) ceramic?
Mark
-
big ten 4
-
kaw rider
If i may be so bold.....how much and from where?
What about you wheels and or trans gears?
The guy at the local bearing house explained that considering the super extra cost, it wasn't worth putting ceramic in the bike's engine or motor. He claimed that the ceramic's real benefits were reduced friction at more than 15,000 rpm and the fact that electricity will not flow through it.
I am really interested in what you 'real world' think. I was in the store pretty late on a Saturday and the guy really didn't seem to want to fill out all the special order paperwork.
:?
Mark
-
bearings
Now are we talking!!! :evil:
Keep up the good work,I?m with you to the end! 8-)
(Mine ordered too)
But carbon rod must wait.... :cry:
-
i did it for other reasons. just to get longer bearing life between crank rebuilds. I have high crank loads. Different motor set ups. the main bearings journals are size wrong on the crank. it needs work.
-
has anyone tried a stuffed wristpin?
-
:-D
-
ceramic bearings are gr8t $$$$. i saw a test on dyno of a street bike wheel bearings helped like 1.2 rear wheel hp. i wounder if anyone has tested them on a 2 stroke motor to see how they would hold up to the gas and oil mix. wounder if they would get surface chamfer . i put slick 50 in my quadzilla trans ( clutch needed replaced ) ran it for a few hours . finished the clutch off. drained it out new gear lube and clutch . shifts so easy that doing 3 gear doughnuts couldn't figured why it would booged . i had bumped the shifter and was in 5th . polish your shift forks and anything else you find that has a ruff edge. not new news just sometimes it helps to be reminded .
-
the main bearing fit on a kx 500 is not right. i know on a 125 it's worth .75hp with C3 bearings.