KX Riders

Maintenance & Technical => KX500 Original => Topic started by: motovet on January 12, 2015, 01:21:05 PM

Title: k5 fuel octain
Post by: motovet on January 12, 2015, 01:21:05 PM
I found a few places where people have talked about what octain to run but I don`t know what, if any mods were done to my bike. Soooooo I guess I am looking for your opinion. I decided it was time to freshen up my ride since I have know idea of it`s history and when I pulled the head I noticed the piston looks like it may be detonating. I always run 91 oct. with kawasaki oil at 32:1 mix, all of the time on this bike is on fast trails and ice riding. The last time it was used was on the ice witch is usually more of a wide open type of ride. I would like to post two pictures of the piston and head but for some reason i can`t make it happen, i tried using the insert image with no luck. If anyone could help me with that also, it would be greatly appreciated. Thank you. it is a 2003
Title: Re: k5 fuel octain
Post by: Foxx4Beaver on January 12, 2015, 01:24:35 PM
you can use this for posting pics....
http://www.kxriders.com/forums/index.php/topic,10040.0.html

are you sure your jetting is adequately set-up for the colder air temps of winter and ice racing/riding?...you may just need to fatten it up a bit.   
Title: Re: k5 fuel octain
Post by: Foxx4Beaver on January 12, 2015, 01:28:13 PM
what year bike do you have?...and do you know your current jetting and ballpark altitude?
Title: Re: k5 fuel octain
Post by: motovet on January 12, 2015, 01:38:08 PM
The bike is a 2003 and i live in wisconsin at about 400 ft.
Title: Re: k5 fuel octain
Post by: Candyman on January 12, 2015, 01:39:42 PM
Jetting?
Title: Re: k5 fuel octain
Post by: Foxx4Beaver on January 12, 2015, 01:40:52 PM
The bike is a 2003 and i live in wisconsin at about 400 ft.

do you know your current jetting?
Title: Re: k5 fuel octain
Post by: motovet on January 12, 2015, 01:42:27 PM
I am running
 pilot          62
 main          178
 air screw    1 turn
 needle        3rd
Title: Re: k5 fuel octain
Post by: Foxx4Beaver on January 12, 2015, 01:48:18 PM
you're plenty rich...how's the plug look...black?

Title: Re: k5 fuel octain
Post by: reklessj on January 12, 2015, 01:48:58 PM
The bike is a 2003 and i live in wisconsin at about 400 ft.
You in northern Wisconsin?
Title: Re: k5 fuel octain
Post by: motovet on January 12, 2015, 01:52:57 PM
The plug is light in color, I live about 45 min south of green bay
Title: Re: k5 fuel octain
Post by: reklessj on January 12, 2015, 01:59:41 PM
The plug is light in color, I live about 45 min south of green bay
Just wondering, I was born in wasburn and have family in Ashland  county. Was thinking bout a road trip this summer lookin for K5 riders along the way to show me local ride spots
Title: Re: k5 fuel octain
Post by: Foxx4Beaver on January 12, 2015, 02:03:51 PM
for the plug to be light in color with that fat of jetting, you "could" have an air leak, causing it to run lean and detonate....
you could do a leak down test...but if you're already thinking about freshening up the motor anyways, I myself wouldn't bother until it was all rebuilt.
some guys like to do leak a down test before they tear a motor down, to find out if there's any areas of concern.
have you got the tools to do a compression test and leak down test?

do you know what the previous owner ran for fuel in it?
Title: Re: k5 fuel octain
Post by: motovet on January 12, 2015, 02:08:41 PM
(http://i1061.photobucket.com/albums/t466/mxvet1/kx/20150112_191902_zpsb1a035a3.jpg)
Title: Re: k5 fuel octain
Post by: motovet on January 12, 2015, 02:19:49 PM
I have the pictures figured out now. will post more of the head and spark plug shortly. Rekless, there is not many trails here so I usually go to upper michigan to trail ride. If your in the are though, I have a could show ya some of the mx tracks. Foxx, I am not sure what the last owner ran, I found it online down in Florida. An older guy had it along with a couple other ones and did not ride it much. I do have the tools to do a compression and leak down test, I will do that as soon as I get it back together. I have the cylinder in getting replated right now, it had some scoring and the intake bridges were cracked sooooooooo as long as it`s apart......
Title: Re: k5 fuel octain
Post by: motovet on January 12, 2015, 02:23:02 PM
(http://i1061.photobucket.com/albums/t466/mxvet1/kx/20150112_190316_zps0eac9238.jpg)
The spark plug has one ride on it, about 2 hours of time. You can see the light pitting on the head along with the piston in the earlier picture.
Title: Re: k5 fuel octain
Post by: Foxx4Beaver on January 12, 2015, 02:24:21 PM
ahhh, excellent!...I didn't realize you already had the rebuild fully underway! :-)
have you chosen/purchased a piston kit yet?
Title: Re: k5 fuel octain
Post by: motovet on January 12, 2015, 02:29:18 PM
All oem parts including gaskets, the cylinder is in at millenium(??? spelling) getting done. I sent the new piston with for sizing.
Title: Re: k5 fuel octain
Post by: reklessj on January 12, 2015, 02:45:45 PM
I have the pictures figured out now. will post more of the head and spark plug shortly. Rekless, there is not many trails here so I usually go to upper michigan to trail ride. If your in the are though, I have a could show ya some of the mx tracks. Foxx, I am not sure what the last owner ran, I found it online down in Florida. An older guy had it along with a couple other ones and did not ride it much. I do have the tools to do a compression and leak down test, I will do that as soon as I get it back together. I have the cylinder in getting replated right now, it had some scoring and the intake bridges were cracked sooooooooo as long as it`s apart......
Right on moto I will let ya know as spring nears. I'm down for any type of riding. Also final ddestination is Mellen, wi , about 1 hr from Ironwood, mi
Title: Re: k5 fuel octain
Post by: DoldGuy on January 12, 2015, 03:44:17 PM
Motovet,

Looking at that piston would have me thinking possible head gasket leak as the intake side looks washed & could also lead to detonation. Most pistons that I have seen detonation marks are on the exhaust. Be sure to lap your cylinder and head together & as Fox noted leak down test.

DoldGuy
Title: Re: k5 fuel octain
Post by: motovet on January 12, 2015, 05:32:05 PM
doldguy,
 Not to sound ignorant, but when you talk about lapping to head and cylinder, wondering if their is something I don`t know about? I have always checked them with a straight edge or used fine sand paper on a good and flat piece of steel to check the head for warpage. Is this good enough or is there more I should be doing?
Title: Re: k5 fuel octain
Post by: Foxx4Beaver on January 12, 2015, 10:10:04 PM
fine sand paper on a good and flat piece of steel to check the head for warpage.

you've got the right idea, sandpaper can and will work fine providing you're careful, but one of our Administrators suggested using this over everything else, and it works great and fast...

(http://i895.photobucket.com/albums/ac152/foxx4afoxx2/ts_zpsec9453d6.jpg) (http://s895.photobucket.com/user/foxx4afoxx2/media/ts_zpsec9453d6.jpg.html)

you can lap them on just about anything, providing whatever you chose, is flat...
I do mine on a 20"x20" piece of mirror in a figure 8 motion.
Title: Re: k5 fuel octain
Post by: motovet on January 13, 2015, 12:37:17 PM
Thank you, I will try that. Never thought about using a piece of glass or mirror, I like that idea.
Title: Re: k5 fuel octain
Post by: DoldGuy on January 13, 2015, 02:15:38 PM
If you still have the head gasket visually inspect it for signs of where / if it was leaking. Dykem is another great way to "see" the low/high spots on both the cylinder or head. I have a big piece of scrap granite to get the parts flat & every KX500 head that I have checked was nowhere near flat, cylinders too.

DoldGuy
Title: Re: k5 fuel octain
Post by: motovet on January 13, 2015, 02:45:50 PM
Thank you, I will make sure I check it over good before putting it back together. I am not sure where to get the time saver compound but got some permatex brand valve grinding compound today, guessing that should work fine?
Title: Re: k5 fuel octain
Post by: Foxx4Beaver on January 13, 2015, 02:55:03 PM
you can get the Timesaver here...you want the yellow label-100N
the 1lb can will last you a while...

http://www.ws2coating.com/timesaverlappingcompounds.aspx

I'm sure you can find it elsewhere too if you shop around.
Title: Re: k5 fuel octain
Post by: Motorrad on January 13, 2015, 04:18:44 PM
Valve grinding compound is bad.
Title: Re: k5 fuel octain
Post by: sandblaster on January 13, 2015, 04:27:02 PM
got some permatex brand valve grinding compound today, guessing that should work fine?

NO!!!!!! DON'T DO IT !!!!  :-o
You will embed grinding compound into your aluminum.
What happens when your engine heats up and vibrates and all those little embedded particles come loose and start floating around in your engine?
Time Saver is what you need...
That stuff is amazing...
Title: Re: k5 fuel octain
Post by: Foxx4Beaver on January 13, 2015, 09:59:16 PM
Dykem is another great way to "see" the low/high spots on both the cylinder or head.
DoldGuy

+1....I use a black Sharpie.
Title: Re: k5 fuel octain
Post by: Motorrad on January 14, 2015, 07:19:49 AM
Just rub some duck butter on it. 
Title: Re: k5 fuel octain
Post by: Foxx4Beaver on January 14, 2015, 07:44:34 AM
that just sounds gross.
Title: Re: k5 fuel octain
Post by: sandblaster on January 14, 2015, 09:41:36 AM
Trust me, it is disgusting.
Don't say I didn't warn you if you take the time to look it up in the urban dictionary  :|
Title: Re: k5 fuel octain
Post by: Foxx4Beaver on January 14, 2015, 09:48:51 AM
Trust me, it is disgusting.
Don't say I didn't warn you if you take the time to look it up in the urban dictionary  :|

hahaha....after reading that, it killed the arousal of even wanting to look it up :|
Title: Re: k5 fuel octain
Post by: umberto on January 14, 2015, 09:52:08 AM
Trust me, it is disgusting.
Don't say I didn't warn you if you take the time to look it up in the urban dictionary  :|

Oh dear God, why didn't I listen to you.  Duck Butter sounds like a playing card from Cards Against Humanity.
Title: Re: k5 fuel octain
Post by: sandblaster on January 14, 2015, 10:43:15 AM
Leave it to Motorrad  :evil:
Title: Re: k5 fuel octain
Post by: motovet on January 14, 2015, 04:18:23 PM
I just ordered a can of the time saver lapping compound, thank you everyone for the help.
Title: Re: k5 fuel octain
Post by: sandblaster on January 14, 2015, 04:58:11 PM
You won't be sorry  8-)
Title: Re: k5 fuel octain
Post by: Foxx4Beaver on January 14, 2015, 08:05:17 PM
I just ordered a can of the time saver lapping compound, thank you everyone for the help.

take plenty of pics of your progress. :-)
Title: Re: k5 fuel octain
Post by: Motorrad on January 15, 2015, 01:24:19 AM
I just ordered a can of the time saver lapping compound, thank you everyone for the help.

I prefer to use atf as my oil base.    But any cheap oil works.   
Title: Re: k5 fuel octain
Post by: sandblaster on January 15, 2015, 02:01:24 AM
I just ordered a can of the time saver lapping compound, thank you everyone for the help.

I prefer to use atf as my oil base.    But any cheap oil works.   

http://www.oem-cycle.com/forum/viewtopic.php?f=39&t=421 (http://www.oem-cycle.com/forum/viewtopic.php?f=39&t=421)
Title: Re: k5 fuel octain
Post by: motovet on January 26, 2015, 03:48:48 PM
so I got my time saver compound and cylinder sooooooooo it`s time to start putting the ole` girl back together. I put a small bevel on the bottom of the piston, checked the ring end gap, .009 on both rings, lapped the head and cylinder,power valve assem. is cleaned and installed and the cylinder is set in place. If things go good, tomorrow night I might be listening to that sweet braauuuup and sniffin two stroke smoke.
Title: Re: k5 fuel octain
Post by: Motorrad on January 26, 2015, 03:56:48 PM
.009".   !!!!    You sure!!!???

If so.  You have something to worry about.....
Title: Re: k5 fuel octain
Post by: sandblaster on January 26, 2015, 04:02:01 PM
I could be wrong and probably am but I think Kawi recommends .006"-.014" for a stock piston???
I don't have my manual in front of me
Title: Re: k5 fuel octain
Post by: motovet on January 26, 2015, 04:11:57 PM
The manual calls for 0.2-0.4 mm and I have .009" or 0.229 mm should I make it a touch more? I am running stock bore with an oem piston.
Title: Re: k5 fuel octain
Post by: Motorrad on January 27, 2015, 12:50:52 AM
OEM piston changes things.   I thought you were on a forged one     still on the tight end though.  Take it easy on her.   
Title: Re: k5 fuel octain
Post by: motovet on January 27, 2015, 04:01:14 PM
motorrad, you talk about forged, what is your opinion between the two? I`ve been told heat displacement and expansion pros and cons both ways. I understand it is on the snug side of its range but when you say take it easy, are you talking forever or during breakin? This bike is usually rode wide open and i do have a ring grinder so I could make the gap bigger if that would be better.
Title: Re: k5 fuel octain
Post by: Motorrad on January 29, 2015, 02:53:38 AM
The harder you run it the more gap you need.  Reason when building a v8 Chevy most companies will give you "street" "strip" "nitrous" ring gap specs.  

Ugly things happen when those ring ends touch each other

better to be slightly larger with your ring end gap than smaller.

I also like to run the bottom ring with more gap than the top ring. (It's a trapped gases thing)

(http://i208.photobucket.com/albums/bb275/Motorrad2/Mobile%20Uploads/20140308_164648.jpg) (http://s208.photobucket.com/user/Motorrad2/media/Mobile%20Uploads/20140308_164648.jpg.html)
Title: Re: k5 fuel octain
Post by: sandblaster on January 29, 2015, 03:24:43 AM
Hmmmm.
Looking very close at that picture for hidden things....  :-D

Is that unit motorized or do you turn it by hand?
Title: Re: k5 fuel octain
Post by: Foxx4Beaver on January 29, 2015, 04:59:42 AM
that work bench is way too clean!
Title: Re: k5 fuel octain
Post by: Motorrad on January 29, 2015, 07:24:55 AM
Hmmmm.
Looking very close at that picture for hidden things....  :-D

Is that unit motorized or do you turn it by hand?

Nothing hidden.    It's powered.
Title: Re: k5 fuel octain
Post by: motovet on January 29, 2015, 11:32:46 AM
Just got done touching up the rings, running .012 on the top and .014 on the bottom ring.
Title: Re: k5 fuel octain
Post by: motovet on January 29, 2015, 01:52:50 PM
the ole` girl is tossin smoke...... sounds happy, man that thing kicks over like a mule. Am going to heat cycle it a few more times and hope to ride this weekend. Thank you everyone for your input.
Title: Re: k5 fuel octain
Post by: Motorrad on January 29, 2015, 03:14:53 PM
Just got done touching up the rings, running .012 on the top and .014 on the bottom ring.


Wise choice