mill head or not??/

[Motorrad]

Thanks for the input. I don't need compression  release but it seems like the other head mods would benefit greatly.

larrys work is awesome..


also.. dont forget Pinnsonault racing...   (in the vendors section).    very good work out of that shop as well...

Id offer to cut it for you...   but Im leaving in a week, for a month and a half long motorcycle ride.... 

[sandblaster]

Month and a half long motorcycle ride?
That goes beyond iron man...

[kelcrist]

Well maybe when you return something can be arranged. money is tight right now so a couple months would be about right for me.

[Brute]

Polar, that brought out a nice "Gafaww" laugh! I think I spit on my screen...

[Polar-Bus]

I don't need compression  release

Wait till your in your late 40's and have hip arthritis like me.....you will want keep Larry's # handy trust me !   

[kelcrist]

Im 43. I have a fair amount of girth to overcome the mighty beasts compression.

[Brute]

Or late 50's... Ten years ago when I had my last KX5 it was MUCH easier to start!?!?!? It is kind of (kind of...) funny that it is harder to kick it 'fast' like I used too also. With the compression release I can bump start it on a hill if one is handy! Nice!

[awak100]

Wait til your 53 and kick it with tennie shoes, that hurts the bottom of my foot. 

[Brute]

You 'ain't really lived until you have kicked and kicked and kicked and kicked a BSA 441 Victor that is in a bad mood! I can still feel that one!

[Motorrad]

You 'ain't really lived until you have kicked and kicked and kicked and kicked a BSA 441 Victor that is in a bad mood! I can still feel that one!

Haha when we first brought our 441 home.  We were kicking it in the trailer..  It kicked back, and threw pops over the bars over the side (3' high) of the trailer out in the street..

No exaggeration.  

[NZ500]

Thanks for info on head mods Motorrad. How wide are your 4 degree sections? The left looks about 25% of the original 15 degree and the right about 60%? I have an AC/DC TIG at home and lathe so can do the more aggressive one (presuming my head would have been messed with before). Much success holding it with a 4 jaw chuck or is a fixture with expanding collets for head holes the only way?

I normally run avgas (105 leaded) or 98 pump. Have new rings and bottom end. Stock port timing and no piston window. I didn't do a compression test before I pulled it apart for comparison. Where should I be aiming for? 160-170psi? Would be good to measure the chamber volume before and after but if it's been done a lot and results are known maybe I don't need to get to worried? Thanks for the help.

[Larry Wiechman]

Much success holding it with a 4 jaw chuck or is a fixture with expanding collets for head holes the only way?

Motorrad posted a photo of a simple head fixture in some other thread. If you say "please" I'll bet he will stick a copy here for you. Proper tooling makes it easy to do quality, repeatable work.

Larry

[NZ500]

Thanks Larry. I remember seeing the photo of that. It looked like a nice set up, I bet it saves a lot of time. But I only want to do this head for now (moving to Australia in September) so I'll have a go at getting it in the right spot using a four jaw first. They're quite an awkward shape is all so might be a fiddle.

[Brute]

Austrailia!?!?!? Where seven out of the ten deadliest critters live? Not to mention all the crazy riders. Here is a vid of 2011 KX450F vs. 2000 KX500 over there with Peter Melton, fast rider for sure! Certain it has probably been mentioned here before.

http://www.youtube.com/watch?v=vau3sOsVxz4

[kelcrist]

so heres an update to my current setup.  i did not mill my head.   i did install the thin optional kawasaki thin head gasket. i timed the powervalve with a bearing and shim setup.    i was also browsing around through the thread of the head mods and i saw the porting of a cylinder and i decided to duplicate that.  it was much easier than i expected.   im sure the cylinder in the photos is a big bore  but it all worked out.         the engine is kind of a monster now..........revs like crazy. i also replaced a couple of worn items when i had cylinder off, the wrist pin was wearing a groove in it and of course i put in new rings. all OEM parts since my piston is a stock kawasaki item.  prior to this the engine was kind of lazy and didnt really pull  all the way through the rpms.       now it does it much quicker.  i had to jet from a  158 to 170 and the pilot from 50 to 58.     so all in all its worked out well.