Author Topic: kx500 outlaw kart motor  (Read 15400 times)

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Offline sandblaster

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Re: kx500 outlaw kart motor
« Reply #30 on: June 15, 2018, 04:19:47 PM »
Port timing


Compression


Skipping 85---
86 had the highest port timing and compression.
89-04 was next best
87 was next best
89-04 was next best
88 was the worst

86-88 are the easiest to port and can all be made to scream.

89-04 can also be made to scream but it takes a bit more effort.

With my new valve design I'm hoping to make some significant improvements on the 89-04 but time and dyno testing will need to be done.
Mechanically I have it operational... Took me three attempts (welding and hand machining) to get what I wanted.
I'm sending my cylinder away next week to get it bored and machined..
I'm also sending in my crank to get it rebuilt.
So I should have something to test in about a month or so...
I hate sending my cylinder off to the competition because they will see what I am doing  :-(
But they will only get half the story without the valves  :-D

I won't say who it is going to either cause I really like the guy but we don't share everything  :evil:
« Last Edit: June 15, 2018, 04:24:27 PM by sandblaster »
The four stroke engine: That's one stroke for producing power and three for wearing the engine out.

Offline dave916

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Re: kx500 outlaw kart motor
« Reply #31 on: June 16, 2018, 02:30:15 AM »
86/ 88 had all almost similiar port timing {120/180duration}
only real differance was main exhaust port on 86 is far smaller

Dont know where clmer got those specs


Offline sandblaster

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Re: kx500 outlaw kart motor
« Reply #32 on: June 16, 2018, 02:41:27 AM »
Hmmm... I did not know that.
I'll have to pull the 88 cylinder off the wall and do some measurements...
Do you have the exhaust port height and width for the 86?
« Last Edit: June 16, 2018, 02:43:35 AM by sandblaster »
The four stroke engine: That's one stroke for producing power and three for wearing the engine out.

Offline umberto

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Re: kx500 outlaw kart motor
« Reply #33 on: June 16, 2018, 02:59:30 AM »
I'll have to pull the 88 cylinder off the wall and do some measurements...
Sorry to hijack a thread, but did you ever get an 88 cylinder head in?  I'm still looking for one...
Perhaps I have a dirt bike addiction?

03 KX 250/88 KX 525/2017 KX250F - Goliath
17 KX250F/04 KX250
04 KX 250 - Lunchbox's Bike
05 KX 125/144

Offline funkj

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Re: kx500 outlaw kart motor
« Reply #34 on: June 16, 2018, 03:25:03 AM »
Am I safe to assume the 86 cylinder is a 3 port exhaust with 2 drum valves and no main port flipper?

Offline dave916

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Re: kx500 outlaw kart motor
« Reply #35 on: June 16, 2018, 03:26:58 AM »
Hmmm... I did not know that.
I'll have to pull the 88 cylinder off the wall and do some measurements...
Do you have the exhaust port height and width for the 86?

yeah i post a pic if in can find it

Offline funkj

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Re: kx500 outlaw kart motor
« Reply #36 on: June 16, 2018, 05:14:10 AM »
86/ 88 had all almost similiar port timing {120/180duration}
only real differance was main exhaust port on 86 is far smaller

Dont know where clmer got those specs



That makes better sense to me.

Offline sandblaster

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Re: kx500 outlaw kart motor
« Reply #37 on: June 16, 2018, 11:23:18 AM »
Am I safe to assume the 86 cylinder is a 3 port exhaust with 2 drum valves and no main port flipper?

Yes, that is correct.
The four stroke engine: That's one stroke for producing power and three for wearing the engine out.

Offline sandblaster

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Re: kx500 outlaw kart motor
« Reply #38 on: June 16, 2018, 11:38:18 AM »
Here is a pic of the 86 cyl.
Note: no decomp scallops and a smaller exhaust port then the 87-88

The four stroke engine: That's one stroke for producing power and three for wearing the engine out.

Offline sandblaster

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Re: kx500 outlaw kart motor
« Reply #39 on: June 16, 2018, 11:55:31 AM »
Here is a 1988 Cylinder..

The four stroke engine: That's one stroke for producing power and three for wearing the engine out.

Offline funkj

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Re: kx500 outlaw kart motor
« Reply #40 on: June 16, 2018, 12:06:59 PM »
Great info... :-o :-o

Looks like for me the 86 cylinder would be the best for and application where your wanting to eliminate the power valve. You have the option of lifting the cylinder or raising/the  exhaust or a combination of both and leaves some options for transfers.

Offline RoostiusMaximus

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Re: kx500 outlaw kart motor
« Reply #41 on: June 27, 2018, 03:21:47 AM »
I don't have head specs for the older K5's but I can tell you that if a 86 top end is done correctly they can be a rocket..


7X KX500 Drag championship winner Jeff Grawbarger uses a 86 top end on this bike with a 89-04 bottom end.
Yes, I know the specs.
No, I can't tell you  :lol:

But I will tell you this... Less has been done to this then you might think..
And that bike is freaky fast...

don't under estimate what all has been done here lol.

Offline sandblaster

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Re: kx500 outlaw kart motor
« Reply #42 on: June 27, 2018, 07:19:23 AM »
I don't have head specs for the older K5's but I can tell you that if a 86 top end is done correctly they can be a rocket..


7X KX500 Drag championship winner Jeff Grawbarger uses a 86 top end on this bike with a 89-04 bottom end.
Yes, I know the specs.
No, I can't tell you  :lol:

But I will tell you this... Less has been done to this then you might think..
And that bike is freaky fast...

don't under estimate what all has been done here lol.

I would never....  :lol:
The four stroke engine: That's one stroke for producing power and three for wearing the engine out.