'99 KX250 Rehab (Budget Rebuild)

[ecdeyzel]

Hi everyone. Hope you all had a good weekend. I finally finished the wheel. Got it trued and put the new tyre on this weekend, with the help of my 14 month old boy

There's a pic of the wheel completed.



And heres a pic of things to come. Still doesn't look like much but there is quite a lot of things waiting to be bolted on. Just waiting to finish the engine.



I am currently looking at wrapping things up with the engine. I took the pin and bearing out of the piston and the pin seems to have a good amount of wear, which means I have to replace it. I can feel a ridge with my finger nail. So will replace those and get a new piston and rings. Will try and get Wossner.



I need some advice on my water pump oil seal. It is very worn. I would like to replace it without splitting the cases. Is there any way to do replace the seal without splitting the cases?

Ed

[ecdeyzel]

Does anybody have an opinion on the waterpup seal? I was thinking if drilling a very small shadow hole in the seal an use u pick to remove it. Will that work?

Ed

[Foxx4Beaver]

that'll work, as long as you're not planning on re-using it.
I use a very small set of needle nose pliers.

[ecdeyzel]

that'll work, as long as you're not planning on re-using it.
I use a very small set of needle nose pliers.

Excellent thanks Fox! Is there no other seal behind it that I can damage or anything else?

[Foxx4Beaver]

I go slow and easy....
here's a breakdown....



what I circled is where you'll be...



you can find vids on youtube that show how it's done...here's one, not the greatest, but you can get an idea...
https://www.youtube.com/watch?v=XapuSwbkU2w

[ecdeyzel]

Thanks Fox. I am not going to take the second cover off. I am going to try and do it from the outside. I only need to replace the outside seal (hopefully) by the looks of it, it's in bad shape and don't want it to maybe get a leak and start wearing on the inner seal. There was no coolant in the oil, so I will leave that till a later stage when I can rebuild the bottom end.

I should be getting a Wossner piston kit for it soon, then the motor will be ready to go back together. I can't seem to get a hold of anyone that does deglazing of cylinders around here. I might buy a flex hone and do it myself, but do you think it's crucial? Will I have to take the KIPS system appart again if I want it done?

Thanks
Ed

[Foxx4Beaver]

I should be getting a Wossner piston kit for it soon, then the motor will be ready to go back together. I can't seem to get a hold of anyone that does deglazing of cylinders around here. I might buy a flex hone and do it myself, but do you think it's crucial? Will I have to take the KIPS system appart again if I want it done?

Thanks
Ed

the problem with that is, you might not have the proper cylinder to piston clearances after honing it out...then you'll just be throwing a new piston into a cylinder that could very well be out of spec, and your ring end gap won't be correct, not good. There is a very slim chance you might get lucky, and have .005 clearance, but not likely. That's not to say it won't run...but it certainly won't be at it's peak performance either.
When a plating company does a re-plate, they require a piston that you're gonna use, so that they can set the tolerances to the correct spec with that piston.

[ecdeyzel]

I see. Thanks Fox. I didn't know this, so good thing you told me. Will it be safe for now to just get the piston kit,  install it and leave it at that? Thaks for the help.

Ed

[Foxx4Beaver]

was the old piston a cast piston?...if yes, you won't be able to just throw a Wossner in it, because they're forged, and require a greater tolerance over a cast piston...and it'll seize up tight once the piston gets hot and expands...probably less than 5 minutes.
At this point, you'll either need to go with another cast piston...I think Pro-X makes over-sized cast pistons in 1/2mm increments(if needed)......or, send the cylinder out to be re-plated, and fitted to the correct tolerance for a forged Wossner.
Do you still have the old piston?
You need to find out what the cylinder bore measures right now, before going any further.

If it were me, I would send out the cylinder, and have it re-plated, and set up for a Wossner...that way you'll know it's all set, and good to go.
I know you're on a budget, and probably didn't want to hear any of this...so you'll have to decide which way you want to go with it. 

[ecdeyzel]

It's a lot less simple than I thought. I appreciate the help Fox. Doing all that will set me back a good couple of months on the build. Is using the old piston and rings an option for now and just replace small en bearing and pin? I can show you photos of the piston, but I will have to wait till we move at the end of the month as I have packed it all away. I also have no idea if it is forged or cast as of yet.

Ed

[Foxx4Beaver]

there's a chance you could use the old piston yes....although I don't recommend it, and would rather not see you go that route.
Will definitely need a pic of it to see if it's cast or forged.
I'd at the least try to get a set of rings for it too, along with small end bearing and pin, if you end up going that route...that will help keep things "tighter", and help prevent/reduce piston slap.

[ecdeyzel]

Ok cool. As soon as I can I will show you photos of the piston. I would like to replace it to have that bit of peace of mind. Thanks Fox.

[Foxx4Beaver]

I would like to replace it to have that bit of peace of mind.

that's my point...no sense putting all this time into it, to have an unfortunate failure.

[ecdeyzel]

Hey Foxx. It's been a while. Had a really rough past couple of months with moving. The KX project is pretty much on hold. After searching my butt off to find where I've put my piston, and after panicing etc, I finally found it in the most obvious place. 'doh.

Here are some pics. Is it safe to say it is a forged piston?















Hope you're doing well.
Ed

[Foxx4Beaver]

Is it safe to say it is a forged piston?
Hope you're doing well.
Ed

that looks like a stock Kawie cast piston...not forged.

I've been do'in good, thanks for asking....been very busy with work...through the month of May I was doing 5 11 hour days a week, money was nice, but doesn't leave much time for any fun activities after work. I'm now back on 4 11 hour days, so I get Fri, Sat, Sun off .

Good to hear from ya!...hopefully you can get back to work on the bike soon.