KX Guru Racing

kwakman:
what did you use to polish head and piston? attention to detail is my motto too, much to my other half's irritation...


Motorrad:
Wet sand with progressivly finer stages of sand paper... then run over a buffer with 3 differant kinds of buffing compound, and 2 differant wheels... (can get you the types if you wish for that much detail).. Remember I restore old british motorcycles.. I know my way around Buffers afro (I own 3 of them)....

head was done the same way, Only with a buffer wheel on the end of a air grinder...

DOUG!!

After alot of beer tonight, I remembered you asking me for pictures of a standard PWK vs the taper bore Sudco... sorry I forgot (takes beer to Jog my memory sometimes)...
But here ya go..

I was reading another thread, and somone suggested going on "the tube" and look up 2 stroke rebuild... I never had, so I did just for fun...

And one thing I see all of them doing is using "raw premix" to coat everything... Sure this works fine for bearings (reccomended)... BUT... a little much for CYL walls, rings etc...

Here is a tip I picked up years ago from a few racers.. (very VERY fast ones might I add)

Thin your Premix out with some fuel.. (I eyeball it now a days, but Id guess 1:1 ?) It makes it go onto Pistons and CYL walls with a NICE THIN coat... I normaly do this to the piston and CYL, about 15-20min before assembly, so it can air dry, (all the fuel evaporate)

A must when your dealing with thick stuff like Castor 927...

Okay. got my wrist pin clips.. Working on final assembly and GUESS WHAT!

I find a machining flaw with my Wiseco piston.. (shock)

the Wrist pin clip spacing is TOO close together..

the 2nd wrist pin clip wont even go half way into the slot... NICE...

SO..

I check the "free play" in the other 3 pistons I have here.. just to see how much Im going to have to grind down the wrist pin to get proper clearance...

1. New style Wiseco (wrist pin bore is too small, have to put wrist pin in with LARGE HAMMER) speced at .025"

2. Old Style Wiseco Speced at .0285"

3. 1987 OEM single ring piston. Speced at .0965"


WOW......

With Kaw Rider finding pieces of metal in the wrist pins, bad machine work, etc etc.. I have to say.

WHAT THE F IS UP WITH WISECO LATLEY?!


To run the same backspacing my other two pistons have (.026)
My PISTON was cut exactly .0425 too close...

Id say its time to look elseware for pistons...

Like to Germany...

Motor is together.. cheesy
Leakdown test passes with flying colors... (still had same pressure/vaccume after half an hour)

Tested squish both ways... (BDI way, and solder)

within .001 of eachother...

gianni2takt:
because I find this topic very exciting because so much time and attention spended on details, I would like to share a little of my experiences again with this forum, despite my last bad experience with it ... I make my boost windows in the pistons today at an angle of 45 degrees upwards in the boost port, so you get a little more boost effect


Motorrad:
Good tip.. I love it when everyone shares..

I dont mind giving away anything I do, as in my kind of racing, its not about horsepower... a kid on a yz80 can beat ya...

And on a good note..

IT's ALIVE... garage is currently in a cloud of castor 927 smoke grin grin grin

Going to let it cool down for a few hours... then heat cycle again..


Its kind of Pieced together at the moment (pipe is just hanging on there by the springs, silencer is ziptyed to frame... etc..

as I am going to have to tear that all off again tomarrow to weld in my Digitron EGT sensor..



Another tip
I know alot of you rebuild motors after things go BANG.... not sure how many FLUSH the pipe out... as yes a 2S sucks air back in from the pipe!..

Flushed mine out... Hmm thats where the rest of my small end bearing was... rolleyes

2nd Heat cycle done....

One thing I have noticed.... its ALOT quieter than before. (motor noise wise).. and many other K5's ive been around... kIPS rattle is at a MINIMUM.. and no piston noise at all...

Also.. noticed how little vibration it has... still too early to tell of course, but so far, the balance factor may be in a good place...

Good:
Great! Did you wind up at 13:1 compression or there about, and are you running a 50/50 blend of 100LL and pump gas?

Also, what radiator cap are you running?


Motorrad:
I am currently at stock Port time settings...(.020 base gasket, .010 head gasket) so yes, roughly... All that will change once I get a base line from stockish, so I can then start to mess with that stuff and know what my "butt" and the "datalogger" are telling me...

For HEAT cycles its just got straight FRESH Premium pump in it right now.. (you can search to find the reason for that on the site Wink
Once it moves under its own power it will be a 100LL/premium pump 50/50 mix.

I always run the "Optional" higher pressure Kawasaki Cap...


Just pulled the pipe to install my EGT probe... took a good look up in there.... (brought the flexy on a stick camera home from work). All is good...

81cr450:
Just a note on wiseco pistons not being what they used to. I was a cr500 guy till I rode the kx 2 years ago , so this is cr500 based but... On the side of the piston they "were" machining the flat spot in by where the pins go, about 3 years ago that stopped . I assume it was just to remove a maching step to make the end product cheaper, but it lost my vote for them having the best piston right there. Just a heavy solid slug.

Definitly X2 on the german pistons

Some great info here it's suprizing to see howmuch can be done with the powervalve details, looks like my build time just went up by a month with all the tricks


Good:
Motorrad, do you plan to continue to run Castor 927 or will you switch to a synthetic after break in?


Motorrad:
Castor 927 for break-in...

Id run it all the time if there wernt powervalves.. Love the stuff...


BUT will be switching to My Synthetic-castor blend I make..
(80% Royal Purple racing, 20% Castor)

Rode it down the street...

Yup... a street legal Kx500 with a HEALTHY motor is more fun than anyone should be allowed to have!..

Thought the clutch was slipping..... till I looked back at the black stripes down the street...