KX Riders
Maintenance & Technical => KX500 Original => Topic started by: kelcrist on June 04, 2012, 02:00:41 PM
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well i have searched the site many times but cant find what im looking for. i have my top end off to address a leaking base gasket. ill put in new rings (OEM) but other than that im just sealing things up. the piston and cylinder are in super shape and the bottom end is solid so i wont be doing anything else. its pretty much entirely stock except for boyesen rad valve, and fmf gnarly pipe.
should i mill my head at all and if so how much or will the short head gasket give me the compression boost i want.
i ride everything, mountains, desert, dunes, hill climb, slow old timer MX............ oh ya and im a bigger guy too, probably 240 with all the gear on.
thanks for the input.....
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Don't need to bump compression, but a good squish design (stock isn't one) will make more power, ping less, get away with cheaper fuel, and run cooler.....
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i would love nothing more than to make every part of the engine as efficient as possible. however, i have to put this thing together and hope it stays that way for one more season. as i understand it, one would need to weld onto the the underside of the head in order to shape the area like you want it. i just dont have the resources for that this time around. ill probably order the thin head gasket and if i dont like it ill just go back to the 1.0 like it was. i am only able to have the head machined cuz a friend will do it for me free , but only a flat cut. i did, however, clean up the intake ports as they were full of ugly flash. maybe that will help some.
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No need to weld to get a good design.
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This will take a while to go through however "Mo" has documented a treasure trove of great info in one thread.
I know the squish angle your looking for is in here but I can't keep my eye's open any lomgner to fiind it,
http://www.kxriders.com/forums/index.php/topic,8717.0.html
I think Mo is saying you can do well by re-cutting the squish angle. no welding involved.
Tuck\o/
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Sorry for the short replys... was on my phone..
(http://i13.photobucket.com/albums/a289/Motorrad/DSC_7265.jpg)
none are welded.
the front right, is more aggressive... more like the ones you were thinking (welding)... but is done without welding.. but you need a fresh uncut head to start with...
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well i have searched the site many times but cant find what im looking for. i have my top end off to address a leaking base gasket. ill put in new rings (OEM) but other than that im just sealing things up. the piston and cylinder are in super shape and the bottom end is solid so i wont be doing anything else. its pretty much entirely stock except for boyesen rad valve, and fmf gnarly pipe.
should i mill my head at all and if so how much or will the short head gasket give me the compression boost i want.
i ride everything, mountains, desert, dunes, hill climb, slow old timer MX............ oh ya and im a bigger guy too, probably 240 with all the gear on.
thanks for the input.....
Kawi makes an optional "thin" KX500 HG. Do some searching I can't remember the p/n off the top of my "head" :D
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ah i see. there is a ton of info out there on this stuff and with the diagrams i was seeing it seemed like you needed to modify the area nearest the gasket. i have plenty of stuff to mess up a good piece of metal so how are you measuring your angles?
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also you said no need to mill head so i assumed welding was needed if you were going to make that area closer to the piston. ????
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ah i see. there is a ton of info out there on this stuff and with the diagrams i was seeing it seemed like you needed to modify the area nearest the gasket. i have plenty of stuff to mess up a good piece of metal so how are you measuring your angles?
Use a lathe... has all the angles for you..
Guess you could do it with a rotary table in the mill also....
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well crap.....i dont seem to have either hahahaha................ probably be best if i just bought one from someone already done.
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Larry W.
http://www.kxriders.com/forums/index.php/topic,6445.0.html
Jerry @ J-Fab
http://www.kxriders.com/forums/index.php/topic,6450.0.html
Both guys are members here and take alot of pride in their work.
Tuck\o/
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Larry did mine and it was so pretty I wanted to just set it on a table top and look at it! He also put in a compression release that was one of the best mods I have done.
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Larry did mine and it was so pretty I wanted to just set it on a table top and look at it! He also put in a compression release that was one of the best mods I have done.
I never realized how ugly my hillbilly green teeth smile was until I saw my reflection in my dome after Larry did my head as well... :D
+1 Larry W. does a FANTASTIC job .
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Thanks for the input. I don't need compression release but it seems like the other head mods would benefit greatly.
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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.... :-D
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Month and a half long motorcycle ride?
That goes beyond iron man... :-D
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Well maybe when you return something can be arranged. money is tight right now so a couple months would be about right for me.
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Polar, that brought out a nice "Gafaww" laugh! I think I spit on my screen...
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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 ! :-D
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Im 43. I have a fair amount of girth to overcome the mighty beasts compression.
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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!
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Wait til your 53 and kick it with tennie shoes, that hurts the bottom of my foot.
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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!
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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.
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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.
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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
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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.
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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
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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.