Interchangable parts?

[ihampson]

Hi, I am a bit confused about which parts are interchangeable.

I am trying to rebuild a 87 250 but am struggling to find good used spares. The r/h crankcase is cracked and the water chamber on the barrel is smashed. I have been told that the crankcases from newer engines (up to 92) will be ok with the 87 internals as there are only slight differences. but the dealers say that each year has a specific set, and the clymer manual has diagrams for 82-86, 87 and 88-91. In the manual some other internals stay the same (shift forks 83-91, shift mechanism 85-91 + kx125 85-91) exhaust advancer assy 87-91, clutch 87-91, primary drive gear 87-91, gear shift 84+) but there is two different gear assy (82-87 and 88-91) How accurate are these diagrams? Are they generic and only show the layout is the same but the parts may have different dimensions? Also the gear assy apears to be completely different. Is the way they fit into the case the same? maybe with different bearings?
I have found a mitaka conrod kit that claims to fit all years of kx, has anybody else used one? did you have to order a specific kit for your year bike? if one size fits all would it be a fair assumption to say the crank is the same?

Sorry for all the questions but i`m new to kx`s and this has got me beat. any advise or suggestions would be greatly appreciated.

[KZ-Rob]

The Kawasaki web site has parts diagrams with numbers, unfortunatly its by model years, not by interchange. Look up the parts in question, if the part numbers are different, chances are they wont work. Kawasaki loves using the same parts as long as possible, sometimes for 30 years if they can.

[CR480R]

I dont know much about the transmissions.. But I do know that the cylinder and crank will definately work in the newer cases...

[ihampson]

Hi guys, thanks for the replies. cr480 i have been reading your other post about rebuilding you kdx engine and it was very interesting. I had previously been told that the kx and kdx shared the same bottom end but using a different top end, and a flywheel weight on the kdx to help bottom end power. I was a bit dubious, thought it might be another urban legend. From the sounds of it your rebuild is going well and would love to hear your progress, was everything straight forward or did it take a bit of modification other than the power valve rod?
Good to see there are some actual mechanics about rather than just fitters, which is the case at my local dealers.
Keep up the good work!

i have decided to buy the con rod kit after the holidays and hopefully it will fit. I also have a top end from a 89 bike which is NEARLY the same to mount as the `87. it fits the crank case, inlet, exhaust etc,  exactly the same, the only thing difference is a idler gear for the powervalve, there is no recess on the case for the stub to fit into. Hopefully i can use a newer crank case so this wont be a problem, alternatively i will have to machine a small hole in the case so that it will bolt down all of the way. sounds extreme but looks quite straight forward. Time will tell i suppose. will keep you posted.
It would be good to create a list of interchangeable parts. maybe we should start a new post and we could update it as we go along? could save us all some money and hassle. And make it easier to find used spares from breakers, ebay etc. What do you think?

[CR480R]

My engine besides the powervalve lever and 2 cylinder studs(wrong length) was a direct bolt together deal... I had an '88 cylinder I was going to use before I bought the '98 and it fit the '91 cases just the same... I wouldnt be surprised if your internals will fit in the newer cases just fine, but I would buy a complete bottom end just to be sure... even if you have to swap in your good crank to make it a runner at least you'll know that the trans is right.

[ihampson]

Any advice regarding the stator and cdi? if the cranks are the same, are the flywheels and would i be able to mount the 87 ignition system? Clymer manual show different cdi`s for different years. they have various amounts and colours of wires so is each one specific to certain models and would it have to match the barrel and/or crank,flywheel .. or do i only have to match the stator and cdi?
the way i see it is if you can mount it and get a spark at the right timing it would be ok? or am i overlooking something that would stop it working? as i said i am new to kx`s and two stroke. all of my experience is with cars.
What are you using in your kdx cr480?

[CR480R]

I am using the Kdx ignition...  I dont know if it will perform as well as the ignition that matches the KX cylinder but its what I have... I have used an '85 Kx ignition on my '84 tecate and also used it with a '84 kx cylinder with great results... I dont think the ignition changes between the years is enough to worry about.. As long as the stator bolts up to the case you should be fine

[ihampson]

Did everything bolt straight on to the crank ok and does the stator bolt on behind or in front of the rotor? i cant remember what mine is like as i haven`t really messed with it as i need a puller before i can get stuck into it. will go and check what mines like ...

[ihampson]

I have had a look at my stator and it is behind the rotor. I have also uncovered some new problems! it took me all of two minutes to take the rotor off with out a puller. the rotor came lose as soon as i undid the bolt and then i saw the woodruff key had sheared off. the pickups seem to be intact and ok but the seal behind the stator is leaking and has been patched with chemical metal (seems like a attempt to cure the leak rather than repair the case, hopefully!) do i have to split the case to remove that seal?

[CR480R]

yeah you have to spit the cases to change crank seals on kawasakis

[ihampson]

Well i suppose i have to split it sooner or later anyways. any luck it will come apart as quick as the rotor! Watch this space to see what other trouble i find!!!
How`s your kdx doing cr480?

[CR480R]

If the seal is bad theres a good chance the bearings need replaced too... As for my KDX I am having problems getting the crank true... I may just end up buying a new one... I still need to alter the powervalve lever, but I going to wait until the final assembly.. Other than that I have everything figured out... I really want to get it going so I can start a new project.

[ihampson]

I thought i would replace all of the bearings, seals and what ever else i found wrong anyway, just for piece of mind. its a long drive to the place my mates ride and the last thing i want is the engine to go bang and i have to sit and watch everyone else have all of the fun!
I have put some specs for your crank in your kdx post, they are from the 82 - 91 manual but could be usefull. is the crank bent or will it not press together true? Sounds like a nice project you got and has given me a bit more faith in getting my bike working sometime soon!

[CR480R]

Yeah pressing the crank myself with out a proper fixture has turned into a mess... its almost within specs, but I am having trouble getting the wheels to move with any sort of control.... If I dont get it dialed in soon I may end up just buying a new one

[ihampson]

Ive never pressed a crank before but a guy i know told me he uses v-blocks and some angle iron to make a jig for the bench press. Cant remember exactly how he explained it but next time i see him i will find out. What are you using to press it at the moment? What do you mean when you say "getting the wheels to turn"? Sorry, i`m new