Maintenance & Technical > KX500 Original
kx500 outlaw kart motor
1901306708:
My couple ideas. Take em or leave em.
Blowdown is way more important than transfer duration.
That center powervalve is a joke. You want a nice clean (as flat as you can get without catching a ring or piston) exhaust port edge to send a good pulse into the exhaust. That's the most important thing of the entire cylinder layout in my opinion.
Going to a bored kehin at 41 added a couple thru the powerband on a stockish engine. If you get a motor that flows, a 44 will add 3-4 on top of that.
The kx is not set up for making power. Need help to make it flow. Gotta do it all to get big gains, otherwise your just talking 1-2-3 hp here and there. Cylinder work, pipe, carb, compression, timing all need major help in my findings on the dyno.
funkj:
--- Quote from: 1901306708 on June 01, 2018, 12:17:51 PM ---My couple ideas. Take em or leave em.
Blowdown is way more important than transfer duration.
That center powervalve is a joke. You want a nice clean (as flat as you can get without catching a ring or piston) exhaust port edge to send a good pulse into the exhaust. That's the most important thing of the entire cylinder layout in my opinion.
Going to a bored kehin at 41 added a couple thru the powerband on a stockish engine. If you get a motor that flows, a 44 will add 3-4 on top of that.
The kx is not set up for making power. Need help to make it flow. Gotta do it all to get big gains, otherwise your just talking 1-2-3 hp here and there. Cylinder work, pipe, carb, compression, timing all need major help in my findings on the dyno.
--- End quote ---
I'm definitely open to suggestions..
1. I'm unclear on you center Pv comment if your suggesting it's removal I'm not sold completely on keeping it. However I'm apprehensive on its removal due to my inexperience. I don't want this a top end peaky narrow band build with a bunch of piston maintenance.keeping in check he has a mid/upper pipe designed around a 8600 rpm and a track that doesn't have to have a top end 200 hp alky motor to win.
2. Also unclear of the blow down comment, maybe eluding to cut the ex-port to desired duration rather than lifting the cylinder and keeping stock blowdpwn transfer numbers.
I appreciate the comments.
funkj:
1901306708
Re read your comment and see where you where going and the importance of port shape and efficacy regarding blowdown and duration not being the only important factor.
It does raise the question if a guy left the center valve at what point can you modify it and know where you have achieved the most efficient usefulness on both ends. Good old fashion R&D.lol
sandblaster:
Here is food for thought...
You are driving very small diameter tires.
Yes, they are wide but you can only apply so much power to the dirt and drive forward and not spin the tires.
From what we learned on the championship kart is that smooth usable power is where it's at.
It's a learning curve based on your track size and conditions.
Sometimes you have to go slower to go faster.
That is why you can go to 10 different tracks with the same set up and some you will do good, others you will get destroyed.
Kart set up and engine tuning will play a huge part in winning and loosing.
Don't over build is my suggestion... it's tempting to do but will hurt you far more then help you.
On your Kart are you using fourth only or are you shifting?
funkj:
--- Quote from: sandblaster on June 02, 2018, 02:54:07 AM ---Here is food for thought...
You are driving very small diameter tires.
Yes, they are wide but you can only apply so much power to the dirt and drive forward and not spin the tires.
From what we learned on the championship kart is that smooth usable power is where it's at.
It's a learning curve based on your track size and conditions.
Sometimes you have to go slower to go faster.
That is why you can go to 10 different tracks with the same set up and some you will do good, others you will get destroyed.
Kart set up and engine tuning will play a huge part in winning and loosing.
Don't over build is my suggestion... it's tempting to do but will hurt you far more then help you.
On your Kart are you using fourth only or are you shifting?
--- End quote ---
I think that track the locals use 3rd/4th.
It's a hard lessons but the simple fact is you can't win with a great motor, poor driving and poor chassis, nor can you win with a great chassis, poor motor and driver or a great driver and poor motor and chassis. But you can win consistently with a good driver, good motor and good chassis.
As far as smooth on dirt in outlaw class it just isn't as critical as other classes and other kart venues that don't have the power to re-cover. I've seen both in outlaw the smooth driver who drives radial preserving corner speed to the guy who pitches his kart and clutches for a big hit off every corner.
I prefer not to put the driver in a motor that he can't carry corner speed without clutching and upsetting /unloading the kart to keep a usable power band or adding teeth and gearing himself out..it's a balance act.
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