Piston Window ?

[powermizer]

Can anyone give me advice on putting a window in my weisco piston on intake side. What are the benifits and downfalls to this. I heard it helps keep the crown cool and bearing gets better lube. Any thoughts on power, loss or gains ?. Please help, Thanks

[MICK]

Not at all saying the benefits would be similar. But KX500 riders are doing this and seeing increases from bottom to top on both the dyno and track testing.

I'm interested.

[powermizer]

Well I know its not a CR5 but what I am putting together right now is my LT500 and am on the edge of putting the window in, from pictures I have gatherd I need something around an inch long and about 1/2 wide. I hope to get some input from anyone here that might have done this on their CR5 or anything else. Thanks

[100hp honda]

ive never examined the lt500, did they have known upper rod bearing issues ? ktm used a window on their pistons for years (my guess is it was there mostly for lube purposes), the wristpin hieght put the bearing very close to the crown of the piston which is exposed to more heat and less lube, also the ktm rod small end did not have any oil holes. persoanlly i wouldnt do it to my cr500 because ive seen no evidence anywhere that suggests it would add power on the honda, and because they have no lube issues,( theres 1 or 2 oil holes depending what brand rod you use) and the wristpin height puts the bearing low and away from the crown heat. as for power, some engines might benefit from a window depending on thier port design, and assuming you knew how big to make it and where to put it. seems like there was something about guys putting windows in banshee pistons but i dont recall how well it worked. ask DR.Q, hes the master with suzukis.

[powermizer]

Yea thanks 100hp, the upper rod does have two oiling holes. DR Q is not going to tell me or anyone squat, either will Glen as far as that goes. Engine mods are a tell and kill situation. I guess you cant blame them, they put alot of time and effort into what they do just to give free advice. I feel on a hill climber you cant get to much cooling and lube,(unless it kills power). I just hoped to learn a little more. Thanks

[thestuz]

can you put up the kx article youve been talking about?

[100hp honda]

go on Qs site and ask. aint like its a big secret.

[powermizer]

Ok ask Glen what size of hole, where to place it, and what effects. Sounds kinda like give spects for port work. Check Q's site out, nobody wants to upset him by giving any info that would realy help. I too would like to see the KX stuff.

[MICK]

I would try to post a link to the topic, but the engine mod thread is only visible to certain (privileged ) members anymore. I suppose I could copy and past it? Seems pretty cheesy to me though

Remember this is a KX500 forum. They're serious about building motors

[Roostius_Maximus]

shoot me a link please, i'm a member over there, just to kinda see what that lime looking stuff is all about

[100hp honda]

trying to bullshit them guys on Qs site probly wont get you a answer

[MICK]

Ok, so this guy is a damn legit tuner. He builds parts for these bikes that Kawasaki Heavy Industries can't compete with. He's personally torn down Factory KX500 rides (Jeff Ward's & Destry Abbott's to name a few) spec'd them all out, dynoed them, and posted all his results. Him and his father own this race shop and pretty much make a living building KX500 engines and dynoeing every aftermarket product available for them...and then building their own to outperform them. Anyways...just a little background. Here's his piston port mod in a nutshell.

That port is .850 wide and centered its .960 from top of piston and it's 1.185 long and it does not interfere with reinforceing ribs in piston or radius under ring package.

That was one of the best mods I have tested for the work and low cost gained 3 hp and 3 - 4 ft lbs of tq and widened the overall usable power in 20 dyno pulls back to back with stock wiesco 86mm piston.

Not an estimate, we gianed 3 horse.

Here are dynos of piston port mod on standered port timing motor, over 60 foot pounds rear wheel tq for over 1000 rpm and over 70 hp for over 1000 rpm 6000 to 7000. 75.47 peak very fast to ride rode this combo 3 hours today took 3/4 turn on power jet...ps, dyno says 24 hp lose thru drive train so 100 at crank.

Just thought you guys would like to know that I took out the first piston I had cut window in after lots of riding and dyno abuse and the under side of the piston which usally looks like baked on carbon is clean as new which I think means less temp on the piston head from the intake window cooling port and the skirt mikes .001 smaller than it did new thats great for that much time on it.

For some reason I feel bad for posting that There are members on that forum who aren't allowed to read that information. Enjoy.

[powermizer]

Ok, so this guy is a damn legit tuner. He builds parts for these bikes that Kawasaki Heavy Industries can't compete with. He's personally torn down Factory KX500 rides (Jeff Ward's & Destry Abbott's to name a few) spec'd them all out, dynoed them, and posted all his results. Him and his father own this race shop and pretty much make a living building KX500 engines and dynoeing every aftermarket product available for them...and then building their own to outperform them. Anyways...just a little background. Here's his piston port mod in a nutshell.

That port is .850 wide and centered its .960 from top of piston and it's 1.185 long and it does not interfere with reinforceing ribs in piston or radius under ring package.

That was one of the best mods I have tested for the work and low cost gained 3 hp and 3 - 4 ft lbs of tq and widened the overall usable power in 20 dyno pulls back to back with stock wiesco 86mm piston.

Not an estimate, we gianed 3 horse.

Here are dynos of piston port mod on standered port timing motor, over 60 foot pounds rear wheel tq for over 1000 rpm and over 70 hp for over 1000 rpm 6000 to 7000. 75.47 peak very fast to ride rode this combo 3 hours today took 3/4 turn on power jet...ps, dyno says 24 hp lose thru drive train so 100 at crank.

Just thought you guys would like to know that I took out the first piston I had cut window in after lots of riding and dyno abuse and the under side of the piston which usally looks like baked on carbon is clean as new which I think means less temp on the piston head from the intake window cooling port and the skirt mikes .001 smaller than it did new thats great for that much time on it.

For some reason I feel bad for posting that There are members on that forum who aren't allowed to read that information. Enjoy.

Thanks MICK, cool stuff

[MICK]

shoot me a link please, i'm a member over there, just to kinda see what that lime looking stuff is all about

If you haven't been granted access to view the "Engine Mod" thread it wouldn't do me any good to send you a link. If you haven't, you wouldn't know it was even there because it won't show up.

[powermizer]

trying to bullshit them guys on Qs site probly wont get you a answer

Mabey but if you look at all my post, never got to many answers, not like here. Just a little kiss a$$ but you guy's kick A$$ over here.

[thestuz]

gotta give it those kx boys. they dont fuck around,

[thestuz]

i think wiseco pro lites have a boost port for the cr5 dont they? the single ring pistons?

[MICK]

gotta give it those kx boys. they dont fuck around,

No they don't

But I should add they don't block most users from the engine thread to be dicks. They just have...umm...about half a dozen serious, and I mean SERIOUS, builders on that site and they don't want their topics getting high jacked and all spammed the fuck out like they get on open forums.

Anyways, my friend with the dead KXF450;
http://www.bannedcr500riders.com/board/ ... 9605#89605
http://www.bannedcr500riders.com/board/ ... 9641#89641
His KX500 motor was built by Stewart. And now it's not the most practical or user friendly motor...it produces twice (read that x2) as much power as my CR does from bottom to top. It's really just sickening. I've been racing 500 2-strokes in H&Hs and MX for nine years...his bike leaves my Fox Honda pants full of baby shit after a couple laps
:whoop: :whoop: :whoop: :whoop:

[thestuz]

think bob needs to pick up a dyno

[100hp honda]

trying to bullshit them guys on Qs site probly wont get you a answer

Mabey but if you look at all my post, never got to many answers, not like here. Just a little kiss a$$ but you guy's kick A$$ over here.

seems the window does prove to add power on the kx motor from what mick posted, but what works on one motor may not have the same affect on another. its hard to say whether you would see the same results on a suzuki 500. im not a regular on Qs site but i do go there from time to time and ive never seen any topic discussing piston windows for the suzuki 500, but i may have missed it. if Q is infact cutting his pistons, the exact dimensions may be top secret but i gaurantee there would be threads about the general subject of piston windows. do a search on that site and you should pull up something to point you in the right direction.

[powermizer]

http://quadracerhq.com/DrQ%20RXd%20500%20Piston.jpg here is a piston that Q has done, but it looks like it might be a stroker piston. Gives an idea to what I might need to do.

[100hp honda]

its hard for me to tell from the photo if someone cut the hole or if wiseco makes them like that. havent you ever seen a lt500 wiseco ? ktm pistons have a hole just like that. at any rate that hole is probly more for lube purposes because of its shape and location which is directly inline with the wrist pin/bearing. i suppose it might add a small amount of power but i really doubt it.

[powermizer]

The piston pin is pretty low on the stock lt500. I just gave up on the hole thing for now, I am still interested in doing it on the cr5. I will let everyone know what I find out. Thanks for all of the suport from everyone. Happy new year.

[100hp honda]

what you trying to achieve is my question ? that kx piston may have gave you some false hope, while it clearly seems it works good on the kawi, that dude probly spent weeks or months to find the perfect size and location for that hole. heres a few things to consider, the intake side of the cr500 piston is a known crack location if the clearance gets too much, cutting a hole only adds to the problem. another thing is i think the new wiseco has thinner skirt than the old version. its a cool idea but you might want to do alot of research before jumping into it.

[MICK]

that kx piston may have gave you some false hope, while it clearly seems it works good on the kawi, that dude probly spent weeks or months to find the perfect size and location for that hole. heres a few things to consider, the intake side of the cr500 piston is a known crack location if the clearance gets too much, cutting a hole only adds to the problem. another thing is i think the new wiseco has thinner skirt than the old version. its a cool idea but you might want to do alot of research before jumping into it.

x2
They determined the KX had a fundementally flawed intake design. It wasn't a spur of the moment, "hey lets swiss cheese a piston" deal. The CR has no such problems to my knowledge. Granted I'm not the guy to make those decisions, but I think it's a safe bet the Honda wouldn't benefit from this work. Like everything else...try it and tell us what you think?

On a similar note, the KX250 ignition doesn't work for squat on a KX500. Totally opposite effect than the 250 ignition for the CR. Just so you know, it's not like comparing apples to apples...