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Hi all

This will serve as a documentation of my 1998 KX250 Restomod. The plan is to repair and replace all worn out parts and build my version of a KTM 300 with a Kawi twist.

Background

I have restored several bikes over the years but i never document them and this is to encourage myself to see a plan through to the end and be able to help others along the way. I bought this bike with a bad bottom end for $400 from a friend who didn't have time to finish it. I have sold the ratty FMF pipe that it came with and will be replaced with a pro circuit variation. This bike will be mainly for offroad duties as i have my DRZ for Sumo, but if i like the power delivery there may be 17"s on the way after the bike is running. here are some starting photos of the frame before cleanup



and some clean pics



old exhaust



and my sumo i suppose



i have some more pictures of the bike on my phone ill upload once i transfer them.

any critique is welcome!
 

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more pics of the kx no real order, just showing the condition i got it in and some tear down of the bottom end.



as you can see she is very dirty and needs a good overhaul before it can haul ASS.
 

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More pictures of the disassembly process

After cleaning

Assembled Bottom end

Hinson Basket

Kustom Kraft 301cc Big bore kit

Here you can see every single cylinder hole has been "repaired" more on that later...

Cylinder Assembly and noting fasteners needed to buy

Mismatched bolts are annoying

Cleaning threads

KIPS valve assembly

New bolts and powervalve assembly

More references for parts to buy

PISTON
 

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Remember those "repaired" threads? yeah here is the result of attempting to torque them

New Helicoil to the rescue

Okay so this next one is Stainless Steel Allen key head studs... bought these AFTER finding out the shouldered OEM studs(which i have brand new in the bag...) wont work w/out a countersunk undamage/repaired hole. so Porsche exhaust manifold stud to save the day

Okay so the last few for this post will show essentially a completed engine. however i have tested the inner clutch cover and it is cracked and leaking. so a new one is on the way and will be assembled for the 7th time.


So to sum up the last few pics and the reason i have to get an inner clutch cover, the back of the shift rod will contact the inner clutch cover to prevent more damage to the engine.. however if not seated all the way (shift rod) it will prevent the cover from seating properly and cause a huge oil leak. Previous owner fixed this by using a bunch of RTV to hold most of the oil, however that didn't stop the cracking of the cover causing a permanent unsealable leak and unfortunately more money spent for me. This post sums up the last few months of research, buying parts and assembly. Ill post more pics of the leaking cover later. Also, i have found out that this is actually a 1997 not a 1998, also that the previously sleeved cylinder was already a big bore 265cc engine. I had Kustom craft cut that out and replate for the 301cc kit not normally available. I now have 1 more oversize to a 310cc for when i rebuild again. Also in the event i have to rebuild a third time then i can sleeve it yet again back down to a 250-290cc. Gotta love the options.
 

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Final Thoughts

The bike absolutely blows every expectation i had away. It feels like a brand new bike and has power for days, ample low and midrange torque that rivals my DRZ400, yet the suspension is smooth and firm. All said and done i have roughly $5000 into this bike and so far it does not feel like a ratty 97 KX250 that i originally bought. I am still in the break in process for the engine so i have yet to feel the full wrath of the 301cc big bore, nor have i been able to fine tune the carburetor, but i have no doubts that it will be a great bike for years to come! I am not finished with the bike yet, i still need to buy new plastics and graphics but my philosophy is it will get dirty and scratched up so they are not on my top priority list. Right now i want to get it running and riding perfectly before finishing off the looks department. This bike had so many hurdles that i had to overcome that i did not fully document in the pictures and honestly i don't feel like getting into all of them, but just imagine building a 20 year old bike from the ground up that didn't have the best life to begin with and you'll get an idea.. Basically everything that could be worn out or broken was, and therefore there really was no area you could have saved money in to begin with. Any normal person would have probably treated this as a parts bike but i am glad i revived this one, i still have more plans with this bike:

Street legal
Supermoto
Separate fork and shock setup for Sumo
Bigger brakes for Sumo
Multitude of graphics and plastics to choose from
Brake master cylinder upgrade
Experiment with gearing setups
18" rear wheel
Newer front fender and number plate (2012 KX450F)
BLACK Rims
Kickstand
High output stator
Possibly a bigger gas tank for enduro/Street rides

And possibly more but that sums up the most of what i have in my head for ideas.

Any feedback is welcome.

Thanks for looking!
 

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Nice, I have a 2007 kx250 sumo on the street. I'm glad your doing this, it will be neat to see what you us it for and how it works out for you!

Here's a picture of mine


Sent from my iPhone using Tapatalk
 

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Discussion Starter #13
Nice, I have a 2007 kx250 sumo on the street. I'm glad your doing this, it will be neat to see what you us it for and how it works out for you!
Here's a picture of mine


Sent from my iPhone using Tapatalk
Beautiful bike! I do have a question for you, what sort of stator setup are you running and how well does it work for your lights? Also, what kickstand are you running?

Thank you for the feedback
 

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I'm currently running a total loss system with a junky lithium polymer battery. I made it so I can charge it by just plugging a extension cord in without removing anything. It works ok, I'm still thinking of a stator set up though. The lights are not quite adequate for nighttime. I'm not really sure where the kickstand is from. It was converted before I bought it. I can take a picture of it up close if you like. It's kinda sketchy honestly, I've had a few issues with it.


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I'm currently running a total loss system with a junky lithium polymer battery. I made it so I can charge it by just plugging a extension cord in without removing anything. It works ok, I'm still thinking of a stator set up though. The lights are not quite adequate for nighttime. I'm not really sure where the kickstand is from. It was converted before I bought it. I can take a picture of it up close if you like. It's kinda sketchy honestly, I've had a few issues with it.


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If you have the time i would like to see how the kickstand is mounted, this is going to be one of the bigger hurdles to jump when making a decision for going street legal. I know i can get a clamp on stand for this bike but i really do not like the way they look, but i have heard they work very well. I originally thought of using a KDX220 kickstand but from my research they have an extra tab welded on the frame..
 

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It works okay, not as stabile as I'd like. But much better then leaning against stuff all the time! I'm thinking it's a cut down trail tech kickstand by the looks of it.


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It works okay, not as stabile as I'd like. But much better then leaning against stuff all the time! I'm thinking it's a cut down trail tech kickstand by the looks of it.


Sent from my iPhone using Tapatalk
I was actually just going to mention that it looks like a trail tech! i dunno if they make those for the 98 or older models though, but i wonder if with some clever drilling i can make that work... i am speculating as to why yours is sketchy, i saw in other pics that yours doesn't have the flat plate on the bottom..
 

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Yea, it's been cut down from original for supermoto. I really don't even know this is even for my bike or not, seems like it's not quite angled for best stability. It's even kinda sketchy on flat concrete lol, I always make sure it's parked where if it falls over it won't hit any cars in the parking lot! But it sure is 100% better then not having a kickstand!


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Discussion Starter #20 (Edited)
I was actually just going to mention that it looks like a trail tech! i dunno if they make those for the 98 or older models though, but i wonder if with some clever drilling i can make that work... i am speculating as to why yours is sketchy, i saw in other pics that yours doesn't have the flat plate on the bottom..
I am doing some cross referencing currently, looking at my two mounting points, the subframe and the lower chain roller mine are closer together than yours, so inorder to make it work i'd have to fab a bit of aluminum as a bracket adapter to fit the new mounting holes.. at that extent i would want the pro moto billet version that they offer for a kx500 of the same year.
 
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