KX Riders

Maintenance & Technical => KX250 / KX125 => Topic started by: CR480R on October 18, 2007, 09:32:12 AM

Title: KX 250 rod, cylinder, and PV questions
Post by: CR480R on October 18, 2007, 09:32:12 AM

I am rebuilding a '91 kdx250 engine to put in my 3-wheeler...  I am rebuilding a '95 KX250 crank to put in it and need to know what the rod side clearance should be on my new connecting rod... I also need to know the allowable crank runout? .001? .0005? I am using a '98 KX250 cylinder and piston was wondering if the powervalve gears should be lubed when top-end is assembled? If so, what type of lube?   Thanks-Justin

Title: Re: KX 250 rod, cylinder, and PV questions
Post by: CR480R on October 30, 2007, 01:05:07 PM

Anybody have a manual?

Title: Re: KX 250 rod, cylinder, and PV questions
Post by: Wizzy214 on October 31, 2007, 09:09:41 AM

are you sure all the parts are compatible?
1991-kdx250 bottom end
1995-kx250 Crank
1998-kx250 cylinder,Head, and Piston

have you tried putting the cylinder head on the bottom end? does the powervalve line up? and/or the cylinder itself?

post pics

this might help

http://www.kawasaki.com/DefaultFrame.aspx?...OOSEVEHICLE.ASP  (http://www.kawasaki.com/DefaultFrame.aspx?...OOSEVEHICLE.ASP)

was wondering if the powervalve gears should be lubed when top-end is assembled? If so, what type of lube?
i always use a little 2-stroke oil, whatever im using for the premix.

Title: Re: KX 250 rod, cylinder, and PV questions
Post by: CR480R on October 31, 2007, 09:22:18 AM

Quote from: Wizzy214 on October 31, 2007, 09:09:41 AM

are you sure all the parts are compatible?
1991-kdx250 bottom end
1995-kx250 Crank
1998-kx250 cylinder,Head, and Piston

have you tried putting the cylinder head on the bottom end? does the powervalve line up? and/or the cylinder itself?

Yes it is nearly a bolt on deal... I need to get the 2 shorter front cylinder studs from the '98...and shorten the lever for the powervalve a bit or get the lever from a newer bike... But thats it...

Title: Re: KX 250 rod, cylinder, and PV questions
Post by: BigGreenMachine on October 31, 2007, 12:07:09 PM

That motor is going to be a real powerhouse in your T3.

Plan on going with an 01 KX250 lump for my T3 after the 5 goes to the 2wheeler.

Title: Re: KX 250 rod, cylinder, and PV questions
Post by: ihampson on December 24, 2007, 08:49:13 AM

Quote from: CR480R on October 18, 2007, 09:32:12 AM

I am rebuilding a '91 kdx250 engine to put in my 3-wheeler...  I am rebuilding a '95 KX250 crank to put in it and need to know what the rod side clearance should be on my new connecting rod... I also need to know the allowable crank runout? .001? .0005? I am using a '98 KX250 cylinder and piston was wondering if the powervalve gears should be lubed when top-end is assembled? If so, what type of lube?   Thanks-Justin

Did you find out. I have a manual but its for 82 - 91 kx`s
In the clymer manual it says -

runout new should be 0 - 0.03mm (0 - 0.001 in) and service limit is 0.05mm  (0.002 in)

rod side clearance  new - 0.45 - 0.55mm (0.018 - 0.022 in) service limit - 0.70mm (0.028 in)

big end radial clearance new - 0.037 - 0.049mm (0.0015 - 0.0019 in) service limit - 0.1mm (0.04 in) Limit seems a lot too me but thats what it says!

Not sure if these specs are exact for your bike but thought i look em up anyway. The parts fit the 91 engine so could be the same measurments?

Title: Re: KX 250 rod, cylinder, and PV questions
Post by: CR480R on January 06, 2008, 01:45:15 AM

Quote from: CR480R on October 31, 2007, 09:22:18 AM

Yes it is nearly a bolt on deal... I need to get the 2 shorter front cylinder studs from the '98...and shorten the lever for the powervalve a bit or get the lever from a newer bike... But thats it...

Ok... I was wrong...  I had to do some mild clearancing on the cases for the connecting rod to clear...