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CSF 10-13-2012 02:40 PM

KTM 640 Winter Project
Hi All,

I recently bought a 2002 KTM 640 Adventure (see pic below). My plan is to give it a through "refresh" this winter. It will be a slow process but, I want to do it right. I don't have lots of experience, but everyone has to start somewhere... I did do a slightly smaller scale tear down, clean, repair or replace and rebuild last winter on my SXF 250.

I've done a lot of research and looking into various bikes like the DRZ, DR, KLR, EXC's, and on and on and on...
I just kept coming back to KTM and to the 640. I get the pitfalls of the bike, and know nothing will be perfect but, I think my 10 year old (almost 11, but I'm holding on to ten for now) bike is worth putting effort into. The bike can do way more then I am currently capable of off road, and I think the 640 is somehow special. I guess everyone thinks that about their bikes though.

Any way, this is my build thread. I'll ask questions here, please tell me if you think I'm doing something wrong or if you can suggest a better way... I'm all ears.

A plan is a good place to start. Here is my to do list for making some upgrades and/or replacing worn parts:

Tires: Kenda K784 90/90-21 and 100/130-18 (ordered)
LED bendable blinkers (ordered)
Heated Grips (ordered)
New Pro Taper Pillow Grips (ordered)
Hella Horns (purchased)
Pro Taper Bar (From Spare Parts Box)
GPR damper - needs to be rebuilt and dial upgraded (From Spare Parts Box, and sent to GPR for upgrades)
Seat recover and possible new foam (looking into local source)
HID headlight conversion and wiring/fuse box upgrades (looking into local source)
Weld on foot peg extensions (friend offered to fab and weld)
Rear shock rebuild (looking into local source)
Rear spring replaced (Possible From Spare Parts Box)
Replace all suspension bearings (looking into source)
Chain and sprockets (Still researching brand, size)
Cush drive bearing (looking into source)

Paint - Fairing, tanks, rack
Design new Graphics - Print install (picture of working design below)

Clean all bearings, inspect, replace or reinstall and lube
Front suspension: inspect, replace or reinstall and new fork oil (forks appear to have been revalved, new seals installed by PO)
Brakes: dissasembe, clean, replace or reinstall, bleed and install new pads.

There's also a billion small things, like a lot of the hardware seems to have some corrosion and will need to be cleaned or replaced. I worked this afternoon on getting familiar with the bike and dissembling it, putting all the parts into organized piles or plastic bags with labels... there is a lot to do.

I'm sure I'm forgetting things but, I think that's the bulk of it. I'll be relying heavily on the KTM 640 index with all of the excellent info there and those that have been here before...

Now its time for a few beers and to enjoy the evening...

jon6.0 10-13-2012 04:18 PM

I bought the correct length and diameter shock spring from Slaven's Racing in Colorado. Good price and a great wealth of info on his site. He has YouTube vids of various maintenance tasks on his website.

Shock Spring:


Might I also suggest the dual electric fan mod:

Depending on mileage you may want to check out your cam bearings:

I've got a newer model fender on mine and I think it looks great:

Tseta 10-13-2012 07:25 PM

While you are there, you might as well gusset/reinforce the subframe. Without reinforcements, it is only a matter of time before it will break.

Good thread here.



bmwktmbill 10-13-2012 07:43 PM

Check everywhere for frayed wires, eliminate sharp edges, dialectric grease on every connection, pull them all apart and grease them.

The cush bearing can be removed carefully, the seals popped and regreased, reinstalled...use a propane torch to heat the carrier for both operations. It is a double row bearing and rarely fails.
Be gentle.

Grease the swing arm bolt, grease the pivot bolt that runs in the frame when you have the shock off.

The HID lights are a great improvement but I hope you are a good man with a soldering iron and electrical tape andd creative. Use the mini ballasts and a separate relay and fuse for high and low.

The front forks have their secrets but there are many old threads. Getting the revalve right is important.

I don't see a kick stand. Not sure how you do that.

Consider a rally bar.

The steering stabilizer is a great idea IMHO.

I hate the racing side cover because it will suck dirt but that's just me.

Lose the supertrapp

Hack off the number plates(it's just me)...

Keep asking.


davesupreme 10-13-2012 08:10 PM

i got a shock spring for my RFS KTM from this place, cannonracecraft..... i think they manufacture springs that are re-badged for the aftermarket.... good price, and they have pretty much any rate you want..... i'm gonna get fork springs from them....

CSF 10-14-2012 05:06 AM

Thanks for all of the info, please keep it coming there's some great stuff there.

jon6.0 - love the newer fender and the look of your 640. Looking into the videos, there is lots of info there.

Tseta - Wish I had a welder... But I think you're right I'll find someone to do that for me.

bmwktmbill - lots of great info thanks. good to know about the cush bearing, it just feels crusty but, I'll give it a good clean and reinstall. I hate spending money on things that don't need it. I forgot to put the kick stand on the list, will definitely order one. The racing side cover will be put back to stock, it seems to let a lot of water in the way it is now. I couldn't believe how heavy that super trap is, Is that a full system from a SMC you've got there? It seems like a good option if I can find one.

davesupreme - great resource, thanks.

When I was taking everything apart yesterday, I found a lot of my connecters (see pic below) were bent or broken. Has anyone found something better I can replace them with, I was sort of thinking about welding nuts in place. I hate being on the side of a trail tring to fix something and have lots of easily lost small pieces...

jon6.0 10-14-2012 08:16 AM

You can leave the head pipes alone. Just get the s-bend and silencer from an SMC.

bmwktmbill 10-14-2012 11:38 PM

When I was taking everything apart yesterday, I found a lot of my connecters (see pic below) were bent or broken. Has anyone found something better I can replace them with, I was sort of thinking about welding nuts in place. I hate being on the side of a trail tring to fix something and have lots of easily lost small pieces...[/QUOTE]Those little fastners don't look like much but they don't vibrate loose and they self center.

Tighten them so they hold by squeezing them or order some new ones.
They are better then they seem. IMHO

dhally 10-15-2012 10:15 AM

I had a 640ADV for several years and yes, there seems to be something "special" about the bike. My favorite parts were the suspension (after tuning) and the huge fuel range.

some suggestions based on my experiences

- Get some motion pro valve feeler gauges and some kind of oil squirter to fill the frame oil.
- Flush coolant system
- Inspect water pump seal and bearings
- Beware - the swing arm bearings are loose needles...
- Might as well replace the speed computer they all seem to fail
- If you're tall might consider lowering the footpegs
- I agree those nut clips work fine. I had my fairing off countless times and never lost one.
- If you ride through water consider sealsavers
- GET a SIDESTAND!! The mounting design for the SW-Motech one is a little cheesy - the bolt breaks plus the bike keeps leaning over further and further. But it sure makes mounting/dismounting easier (possible). I think there's another one available that requires welding, may be a better solution.

CSF 10-18-2012 05:08 PM

Swing arm & rear suspension work...
a few updates...

got some goodies from the UPS man today, sorry got excited and forgot to take pics. Tires, 4 LED blinkers, Electrical harness for a few upgrades (I'll expand on this later), and some other smaller stuff... also ordered the side stand, so that's on its on its way...

onto the real work:

I disassembled the entire rear end. It's just an engine in a frame with a unclad front end. Reminds me of a half gone zombie still sort of crawling along...:cry

It all seemed to go fairly well considering the previous owner had mentioned that some maintenance had been perhaps neglected... it seems however the first owner (I'm the third) may have put some effort into the bike. At first inspection I thought everything was pretty much toast back there :puke1. And some of it is.

The swing arm, one side was in salvageable condition and the other was completely destroyed:
So, should I replace both?

The frame bearings don't look great, I still have to get these a bit cleaner before I can make a call as to their serviceability, there did appear to be some very minor corrosion, some WD40 seemed to wash it away:

And the one I was really, really worried about. The linkage... this almost looked brand new after a heck of a lot of cleaning:

I am somewhat concerned about the Prolever bearing though. It seems to have some lateral play (side to side), not sure if that's normal or a sign of wear. It spins and twists very freely, if someone could chime in on that one, I'd appreciate it.

The LC4 thread index has been extremely helpful for all of this, glad I have all of that info at my finger tips..

That's it for now...

Droptarotter 10-18-2012 05:38 PM

I would do both swing arm bearings together.

The frame bearings can be a bugger to get out if they need replaced........I posted some photo's somewhere as to how to remove them........also put in a grease nipple so you can lube those frame bearings.

Check post #153 of this thread....................

It looks to me like the seals for the frame bearings are installed incorrectly. They should have the spring on the outside. They are placed that way to keep water/dirt out and if you install a grease nipple, the excess grease will be able to get out without pushing the seal out.


CSF 10-18-2012 05:49 PM

Yea, I'm thinking its probably best to get a swing arm bearing kit like this and do everything while I've got it all apart
( )

Just ran out and looked at the frame seals, there's a spring at the outside...

5 speed 10-18-2012 06:50 PM

Good on you to take care of your bike! I would tear mine down for the winter but the weather is just now getting ready to get good. I live in Florida and it was still about 85 degrees today. July Aug is the months that I dont ride much because of the heat, problem is the garage is about 100 degrees. However I just did some work to my 950 and she is ready to go. Good luck on the rebuild. PS I had a 625 and while the LC4 has quite a bit of vibration it is just like a sewing machine and never failed me. That bike was special.

bmwktmbill 10-18-2012 11:38 PM

How's the swing arm bolt look, it's half the bearing?

sailah 10-19-2012 04:55 AM

As a SOP I always replace any bearing I remove or even look at. I replace wheel bearings halfway through the summer. has a great selection of bearings in both cheap and not so cheap versions. For long term bearings I like the Nachi brand, made in Japan. For wheel bearings and such I use the standard chinese ones, they are getting replaced soon enough.

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