k5 compression ???

[bellracing2]

Do you guys have a hard time checking compression ? every time I would go to kick it , it would try to throw me over the bars ! I could only get about 5-6 half a$$ed kicks , and all I could get is 175 . What is your psi at ? what psi do you need to start running race gas at ? I have a midrange ping I 'm trying to get rid of , and am starting to wonder if I have too much comp. for pump gas ? What is the min. squish for pump gas ? I'm gonna try out the jetting specs from the chart this week , but they are only 1 step away from where I was . Thanks .

[bellracing2]

anyone ? this is a fresh topend and I dont want to burn it up . Thanks

[FuriouSly]

Higher compression tends to need more Octane.  Before messing with the jetting anymore, get some race gas (105+ preferably leaded) and mix it at least 50/50 with premium unleaded.  Try it out and see if your midrange ping goes away (probably will).

What premix do you use and at what ratio?

All motors are different and tend to need individual set-ups to run good (think of a guitar-10 may be made the same day with the same materials, but each have to be set-up seperately to get the best performance).  That is where knowing how to tune and diagnose problems comes in handy and neccessary.  If your bike has a new top-end and everything else (carb, reeds, ignition, crank/tranny, air filter) is in proper working condition, then start looking at the fuel and needle clip position (may be a little lean at 1/2 throttle-move the needle up-clip in the middle).

Sly

[Danger4u2]

When I read your thred I thought when you said "you could only get 175 psi" that was the high end.  I went to my factory service manual and found:
 
Cylinder Compression (Usable Range):

KX125 : 109-171 psi

KX250 :119-185 psi

KX500 : 105-164 psi

You are 11 psi over the usable range.  The book says that would be due to carbon build up (not your prob with fresh top end) or incorrect gasket thickness.  Throw in the 111 octane race gas and go.  Or stay out of the mid range and keep it WFO, just joking.  Sounds like high octane should get rid of the ping.  Let us know how it turns out.  Please keep us posted.
Danger

[bellracing2]

Thanks for the info guys ! I see Kaw oem offers 3 different head gaskets for the 5 . Do you guys know what each one is and how thick ? Maybe I got the wrong gasket ? What about the squish ? that will tell me right away what is going on , I know how to do it , just don't know what the min allowable limit is for pump gas ? I would ideally like to get set up for 87 oct so I can go safely anywhere ( I ride in the UP of Michigan , and northern Wisconsin , so Race Gas is NOWHERE to be found )  . I raced my buddies 400 suzuki quad and that was kinda funny  . I should have gave him a chance and started backwards ! What reeds would you guys reccommend (cheap as possible = no v force or rad valve ) ? Thanks Again , for the help ! 

[gowen]

I've always gotten high compression with a new top-end. Usally once the rings set, it goes a little and gives a little more room. Is the cylinder fresh too or just the piston? I don't see a need to run race gas with the KX unless you've done some serious work. I had my head and cylinder cut for race fuel and had to run it. I purchased barrells of C12 from VP Racing to keep it alive. Infact, I still have about 30 gallons of it sitting. I don't even know what to do with it. Maybe run it in my street bikes or MX bikes? lol

Goodluck

[bellracing2]

yup , it's a fresh 88 mm milenium tech re-plated and new wiesco . But I'm unsure about the head gasket now as I see 3 different ones are available ? Top end runs great , low end runs rich , and the mid pings . I just put in the 58 pilot (had a 60 ) , and lowered the clip to the mid (was in 2nd from top )(stock needle) and put in a 168 main (has 170 ) . I hope to be close 

[gowen]

Keep playing with your jetting, if your lowend is rich and you are sure about your crank seals, ect. Try loweing the clip 1 more to see how it results. Believe me, even if it is running a little rich you are losing power and fuel.

[gowen]

yup , it's a fresh 88 mm milenium tech re-plated and new wiesco . But I'm unsure about the head gasket now as I see 3 different ones are available ? Top end runs great , low end runs rich , and the mid pings . I just put in the 58 pilot (had a 60 ) , and lowered the clip to the mid (was in 2nd from top )(stock needle) and put in a 168 main (has 170 ) . I hope to be close 

PS: Check the forsale forum. I've got a few needles, pilot, & mains if you want some experimenting jets to help you.