250 98 Kawi restoration

[If you don't want to read the story of my bike, you could still read the last few lines of this post and maybe give me an help! :wink:]

Hi everyone,
as I said quite some time back when I registered on here, I would like to share with you the ongoing restoration of my 1998 KX250. So here we go!

The first step, before even jumping on it is, as any of you probably already knows, cleaning it thoroughly.
This were my two duly companions on this part of my job, together with an awful lot of patience and even more time.
IMG_3586.jpg

Then it was time for the "spend a lot and ride close-to-nothing" step.
The bike wouldn't stop when I got it and the front brake lever was really hard. So I set out to check the brakes.
This is what I found
2014-09-23 15.12.48.jpg 2014-09-23 15.13.04.jpg
If you think it doesn't look that bad wait for the next pic
2014-09-23 16.08.39.jpg 2014-09-23 16.08.49.jpg
It took me more than an hour to clean it properly. Promise, I'm not exaggerating this. Can you imagine 16 years of dirt and mud getting in there and being cemented by the heat of the brakes?
Plus the pistons were blocked and the rubber boots covering the floating pins were (and still are to be honest, as I left them that way) bashed. And if that's not enough to you, the screw that's working as a pin to keep in place the brake pads is blocked (how do you say in english when the head of a screw is damaged and you can't take it out by simply unscrewing?). Which is why I left in the old pads in after I gave them a nice rubbing with a file. Before:
2014-09-24 16.00.31.jpg
And after:

2014-09-24 16.00.36.jpg 2014-09-24 15.42.48.jpg

Looking good now
2014-09-25 08.59.24.jpg
I'm sorry I haven't posted a proper pic of the bike! Will do soon!

Now comes the part where I need your help: I got the pistons out and, as it turns out, some butcher had a go at it before me:
2014-09-24 15.12.04.jpg
Considering it took a lot of effort and some light hammering to put the pistons back into their place, and that although it's now stopping pretty good the brake lever is really hard to pull, could it be that those signs have ruined the piston and cylinder? And now the piston isn't moving very well, even though it's been cleaned?
 

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Did you sand them with some 320 grit before you put it back together? It would take the ridge out of those gouges in it and should free up the pistons alot depending on how rough they are
 
I just rebuilt a 98 KX250 motor 525.00 in parts. Funny set of power valves with all the gears and such. I am so use to the YZ set up it looked foreign when I disassembled it. I have a 2000 KX250 ready when the kid comes up with 500.00 cash minimum and working on a 1988 YZ250 now. Not much available for it any more. Power valve is messed, I am going to have to Macgyver it back together. Good luck with the rest of the bike....
 
Probably could have just replaced the whole thing with less aggravation.

Apart from the fact it's not very easy to find, you probably need to look around for something that's not coming out of a 98 kawi as over here people seem to only buy KTMs, in which case you need something with the same dimensions, and that something would either cost around 200€ (250dollars) or come in worst conditions than the thing I am replacing.

Did you sand them with some 320 grit before you put it back together? It would take the ridge out of those gouges in it and should free up the pistons alot depending on how rough they are

Yeah put it on a lathe and sanded it
 
Yes it is a Nissin. I've cheked on ebay before getting through the trouble of cleaning it and I found more than a few ones. The cheapest are coming from the US at around 30€, to which you need to add another 30€ for shipping and unknown fee at the border. Over here it works like this: the thing gets to the border with a document from the seller stating how much it is worth. They normally add 20% to that price in taxes. If they don't believe what's written on there, they give it a value and tax you on what they think it's worth. So you never really know how much you'll spend.
In Europe I could only find things somewhere north of 180€.
The way I did it I only spent a coffee for the guy who's put it on the lathe.

ps sorry if my previous post sounded rude, didn't mean to
 
I just rebuilt a 98 KX250 motor 525.00 in parts. Funny set of power valves with all the gears and such. I am so use to the YZ set up it looked foreign when I disassembled it. I have a 2000 KX250 ready when the kid comes up with 500.00 cash minimum and working on a 1988 YZ250 now. Not much available for it any more. Power valve is messed, I am going to have to Macgyver it back together. Good luck with the rest of the bike....


What is wrong with your 88's power valve?
 
Yes it is a Nissin. I've cheked on ebay before getting through the trouble of cleaning it and I found more than a few ones. The cheapest are coming from the US at around 30€, to which you need to add another 30€ for shipping and unknown fee at the border. Over here it works like this: the thing gets to the border with a document from the seller stating how much it is worth. They normally add 20% to that price in taxes. If they don't believe what's written on there, they give it a value and tax you on what they think it's worth. So you never really know how much you'll spend.
In Europe I could only find things somewhere north of 180€.
The way I did it I only spent a coffee for the guy who's put it on the lathe.

ps sorry if my previous post sounded rude, didn't mean to


I give you guys on the other side of the pond a great deal of credit for fixing what is already there. Heck, I learned about using the front brake to pump fluid back through the bleedouts on the back brake and vice versa to bleed the air out from one of your neighbors.
 
What is wrong with your 88's power valve?

Two halves separated for a while in there. Allen bolt was loose, pins wobbled the holes oblong. I'll post pics in another thread. Probably random photos on Monday.

And no IAPPO, not rude at all.
 
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if you want them to work like new and you cant get new ones, it looks like some money spent with a machinist. not really familiar with the model.
 
I've finally managed to get the Kawi in its places.
And that's hasn't been a simple task as, in the process of preparing it for her first laps, I found out that:

-it had worn back wheel bearings, which I changed. Please note my super-awesome bearings aseembling tool
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This is what it looked like before
IMG_3582.jpg
By the way, does anybody know why they put 3 bearings in it? That's kinda strange.

While I was there I decided to remove the tyre and get the wheel centered and the spokes tightened.
I've also painted the disk in gold, for added Brembo-ness, and of course because gold is the fastest color for a disk :smirk: that's helped me drop my lap times of 5 to 10 seconds, depending on the circuit
IMG_3711.jpg 2014-09-24 17.48.58.jpg

-while checking the back wheel bearings, I realized that the hub had a small crack in need of attention:
2.jpg
so I welded it, and I have to say I'm absolutely pleased with the end result

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SRAD97750

Moderator
Staff member
Good stuff! :clap:

Three bearings in a rear wheel, two on the drive side.
The torque from the engine on the chain is enough to destroy a single wheel bearing in no time.
-BIG DAN:thumb:
 
Good stuff! :clap:

Three bearings in a rear wheel, two on the drive side.
The torque from the engine on the chain is enough to destroy a single wheel bearing in no time.
-BIG DAN:thumb:
Yeah the fact is it's not a very good design on paper. You need to set a greater hub to bearing tolerance to avoid bending the shaft while mounting it. In theory a double row bearing would have been better avoiding that problem. probably the fact that the wheel is rotating at relatively low rpm and that changing a double row bearing would cost a fortune has moved them to use two bearings.

Switching off engineer mode now [emoji1]
 
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