KX250 rebuild - after all I've ridden it half a dozen times and it's worn out

**Pornstar** · 4th May 2011, 01:25

Originally Posted by Arronduke

Did a little more pulling apart tonight... main aim was to have the frame and swingarm ready to go to the powder coaters tomorrow.

Everything was going fine until it came to removing the collapsed swing arm bearings... the swingarm bolt had started working its way through the side of the bearing shell....

and there are two bearings on each side and both on one side were rooted. there is nothing to hit them out with and they are in there very tight.

Time to start up the arc welder and put some weld on the inner shell and shrink the shell and give me somthing to hit...

removed, if these had been left much longer it would have been very bad for the swingarm so from that point of view its all good.

Spent my first few dollars last night..

FMF Fatty pipe $238
FMF Power Core silencer $109
Pivot works bearings and seals for the swingarm, steering head, shock and linkage .. all from the USA landed for $200 plus freight of $98. So total is $644 NZ.

Quite happy with the price as I have seen a FMF fatty on trademe for $475.

Score, which site did you buy from?

**Arronduke** · 5th May 2011, 19:59

Found them on the net... basically I search around looking for a company that a) shio to NZ... b) shipping costs where reasonable...

**Arronduke** · 5th May 2011, 20:03

The frame, swingarm and subframe are at the powder coaters...

Silver and orange for the frame want it to look like a KTM....... should look cool.

**Arronduke** · 6th May 2011, 21:33

Measured the cylinder tonight and have the following measurment as follows..

Cylinder new 66.400 - 66.415
mine averaged at (telescopic gauge and digital varinier) at 66.43 and 66.41 at 90deg.

Service limit 66.48
So based on that we are good to go.

Only issuie is cylinder wear... pitting looks bad but can't feel it with my finger..

and a couple of scores on the cylinder which i can feel.... with my finger nail..

I'm thinking this will be OK..

Piston skirt clearance new 66.35 old is 66.30 service limit is 66.17... but i have a new wisco piston and that measures at 66.33.

But why the differance in pistons... old has a cut out new wisco does not... anyone have an idea on this/

cleaned the power valves also.. noticed the bottom of them are broken.. the whole assebly was well seized. But looks ok.. cleaned it and re assembled it and it seems to work ok. My guess is the broken bits will not be a problem... please tell me if I'm wrong.

Just for interest this is whats left after pouring out the oil... no shit its like clay... now you know why I am seperating the cases... and I plan to make a crank seperation tool myself.. piss easy.

not good i say...

Look at this dirt and shit...

**Arronduke** · 6th May 2011, 21:57

Engine on the bench..

Needs a good clean..

Soaked the barrel in de greaser all day and the carbon shit is still there... anyone know how to get rid of this shit? other wsie looks mint..

next picture is cylinder soaking in degreaer for the day... looks great.

Best part of the day was getting my frame etc back...

looks cool.

**vr4king** · 6th May 2011, 22:40

Oven cleaner for the carbon build up might take a few goes but works

That cylinder doesnt look good you priced up a sleeve for that bad boy?

Also heard that some wiseco pistons need holes drilled in em might be worth looking into............I could be wrong here we used a Namura one on the rebuild i did.

The old KX's you gotta get the cylinder measured right we had one throw a piston as the cylinder was tapered and bigger at the bottom which caused it to rock over and explode big time we were shovling alloy chips out the exhaust port even before it was torn down.............Lesson learned

**flyingcr250** · 6th May 2011, 22:42

must be a few people doing up old kawis, saw another green frame at the powder coaters in cambridge when i went to pick mine up

**Arronduke** · 6th May 2011, 23:09

Flyingcr... it was me..!!! I picked up my frame today from NZ Powder Coaters... they are the best.

**barty5** · 7th May 2011, 01:57

hey dude went and had look at bits on frame and those tank bits are there also was looking at those power valves it got the better of me had a look and although ours is a year older and a 125 looks like the part numbers are the same we are going to be stripping the motor for parts as well due to the guy not buying the other day if your keen ill see what they look like condition wise

**flyingcr250** · 7th May 2011, 06:23

Originally Posted by Arronduke

Flyingcr... it was me..!!! I picked up my frame today from NZ Powder Coaters... they are the best.

ha ha ha, that was me picking up the orange frame. yea they do a pretty good job, cheap too, sandblasted and powdercoated for $130

**Jay GTI** · 7th May 2011, 08:14

Originally Posted by flyingcr250

ha ha ha, that was me picking up the orange frame. yea they do a pretty good job, cheap too, sandblasted and powdercoated for $130

Orange frame... mmmmmmmmmmmmmmmmmm

(would love to do the same)

**Arronduke** · 10th May 2011, 18:51

Flying CR... your orange frame looked mint...
Dam small world I say.

**Arronduke** · 10th May 2011, 19:07

Originally Posted by barty5

hey dude went and had look at bits on frame and those tank bits are there also was looking at those power valves it got the better of me had a look and although ours is a year older and a 125 looks like the part numbers are the same we are going to be stripping the motor for parts as well due to the guy not buying the other day if your keen ill see what they look like condition wise

Yes please.... PM me with cost... what about the swingarm adhuster bolts? and throttle.... Oh and the power valve parts would be most cool.

**Arronduke** · 10th May 2011, 19:15

Originally Posted by vr4king

Oven cleaner for the carbon build up might take a few goes but works

That cylinder doesnt look good you priced up a sleeve for that bad boy?

Also heard that some wiseco pistons need holes drilled in em might be worth looking into............I could be wrong here we used a Namura one on the rebuild i did.

The old KX's you gotta get the cylinder measured right we had one throw a piston as the cylinder was tapered and bigger at the bottom which caused it to rock over and explode big time we were shovling alloy chips out the exhaust port even before it was torn down.............Lesson learned

Thanks for the info... I will take it to a engine reco man and get it measured up correctly.

Anyone recommend someone who is farmilar with MX bikes?

Resleeve... big bore 310cc

...... naaa Thats just been stupid. I think it will be just fine as long as it measures up ok... if not I will worry about it then.

**Arronduke** · 12th May 2011, 19:28

Fun bits arrive today... cool.

I was pleased to see the box sitting at the top of my driveway when i got home.. I was worried that I would be paying GST on this @ about $94... and that would sux.

Grabbed a beer for the occasion and headed out to the shed.

Beer in hand and I opened the packing slip... The packing slip was in US $ and was for $232.32 + $84 shipping... and guess what the fatty pipe is not listed on the packing slip

And I feel gutted. Stood there thinking I don't need this shit.... Then i think.. dam that is a large box for whats listed.

So I open the box and bugger me... it all there and one nice big FATTY pipe..

.. Don't know if it was a mistake or they did it on purpose but OEMCYCLES.COM just saved me a heap of coin... I could not be happier.