Nitpicking '02 520SX

Strick

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#16
1. The return throttle cable frayed at the pulley.
--never heard of this happeing before (gorilla grip)

2. Rear sprocket bolts come loose every ride, even with Loctite Blue.
--I always use red on the rear, and I can always get them off when needed

3. Rear spokes break.
--I have heard of front and rear breaking (probably too tight from factory)

4. Sides of seat cover turned milky color (moisture under cover?)
--common - waranty

5. Front and rear brakes squeal (fronts discussed elsewhere in this forum, but I had to mention it).
--common esp. front (mine went away over time)

6. Rear brake master cylinder seal failed. Hopefully a fluke, dealer covered under warranty, but is this going to be a recurring problem?
---fluke, I hope, never heard of before.

7. Airbox fasteners come loose and fall out (band-aid fix is to cover the holes with duct tape).
--you have to get used to how to properly fasten these. on my 1st KTM I had issues.

there's my .02
 
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#17
Unless you put some zip ties on those dzuz fasteners you will loose them.
All it takes is the right combat conditions.
I have had 5 KTMs since 98 and without the zip ties sooner or later the little
metal keeper fails.
I personally have never had the cables fray except right at the throttle ball on one of the 99 380s I owned.
But it had about 50 mx races on it and a zillion practices.If it wasnt a braided cable it would have failed sooner.
I dont get concerned about the brake sounds.
I take a little sand paper to the pads once in a while to clean out the grit that
gets inbeded plus it helps with stopping.
The hubs usually fail due to improper spoke tension and overtightening the axle nut repeatedly.I dont suggest driving in wheel bearings either its better I think to press them in . Form a gasket has proven to work on sprocket bolts for me anyway. I think being more pliable and not hardening
makes it less likely to fail from repeated shock and vibration. I prefer loc tight red but the form a gasket will substitute if loc tight is unavailable.
All these things can be avoided and in my opinion are pretty much not a concern. KTM warrantied a hub that was starting to crack on my 01 520 but
there was evidence it was a production glitch.
I was able to buy a spare wheel assembly from MIDWEST KTM in Valpo In
for $280.00 less disc and sprocket. I thought that was a pretty good deal.
 

380EXCman

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#18
The whole time I owned my KTM I never lost an airbox fastener. I always made sure they were clean and completly fastened. As for the spokes I never tightened mine I would tap and wiggle them when I washed it, if I found one loose I would tighten "it". But I maybe only found 5 loose spokes the 2 years I owned it. I never found a loose sprocket bolt on my bike. I checked them every few rides or so. When I replaced the sprocket I would use new bolts with the blue loctite. Hiff Hiff Im starting to miss that bike. Sure was a good one.
 
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#19
Katoom Blues

I think riding strictly mx has allot to do with the what some of us are experiancing with our bikes.
My good friend has had a 98 250sx and never had loose spokes or lost any air box fasteners.
His bike has been ridden primarily in hare scrambles.
and 40+mx occasionally. He is an average rider.Not a jumper or real agressive.
Jumping 70 foot doubles that loft you in the air 15-20 feet and banging into other bikes on a mx start causes some of these problems.
I have been through my share of spokes on any bike I have raced
There was a time when you didnt go to RED BUD without spare wheels because until they brought in the sand it was rock city.You were lucky to leave without a flat or worse a spoiled rim.
The problem with the air box is the little washers they use.
Several of mine have stayed on but were split on one side.
The zip ties held it in place .
The guys I know with KTM,s that are B and C riders arent having as many failures as the A riders. I think it matters how often you ride and how hard you ride. Out here on a practice its common for most of the A riders to ride a tank of fuel out on one practice moto and 3-5 gallons in one afternoon.
These are hard laps not playing around.
The bikes really get abused. The preventative maint . is being done
but things break when pushed after a while. Nothing lasts forever.
A little trick here and there insures not having to buy the little $28.00 fastener. As far as the rear wheel well here we are wanting a light weight 4 stroke but we arent willing to sacrifice durability. This is a hard thing to accomplish. Excell rims have been made the same for years but the bikes keep making more power and torque. The 98 sx wheels were stronger than the 01 and 02 wheels but are heavier. My 380sx bikes made a bunch of power and you had to keep an eye on those spokes and hubs.
The 520sx makes even more torque. Have you ever noticed how the rim locks bend ? There is some serious power being put to that back wheel.
I personally am starting to think the did rim on the rear is the way to go as far as rim strenghth. Yes the excells are lighter but they bend easier. Maybe the new style is the way to go I really dont worry about it.I
keep an eye on it race it if it fails fix it. I think the KTM is still the most reliable
bike made and speaking for myself has saved me more money than any other make. Now the AMA takes it all.;)
 
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MXFastGuy

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#21
Originally posted by Bud-Man
MXFastGuy,
You may want to check your chain tension. It could be contributing to some of your problems. Most new KTM owners tend to over tighten the chain. A good way to check is to take the shock off the bike and move the rear wheel through it's travel. This may sound time consuming but it's not. Just remove the two bolts holding the shock on and slip the shock out. Once you get the proper tension, find a place to measure the chain slack so you can quickly adjust the chain as it wears. I can't say this will solve all the problems as I still broke spokes after I correctly set the chain tension, but it's a start.
I finally got around to doing this today, and boy am I sure glad I did! I would never have guessed the chain would have to be set so loose. I was running it loose by Jap bike standards, but when I checked it w/out the shock per Bud-Man above, it was super tight. By my measurements, with the bike on the stand, the slack measured at the rear of the chain buffer should be 70mm (just under 3 inches). This is measured from the top of the swingarm to the bottom of the chain. This gives just a slight amount of freeplay with the chain at its tightest point.

Hopefully this will keep my sprocket bolts from coming loose so often. I guess I'm lucky I haven't broken a hub yet.
 
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#22
Rear Sprocket

Double nut the Rear sprocket. Lock two nuts together. That will stop them from coming lose. :blah:
 
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#23
Wow thats a late response. lol but at least it got me looking.

Some OLD info to match the response.

w*w*w.users.bigpond.net.au/Mr2/rpm/2002ktm400exc/2002ktm400exc.htm

DELETE the * to see web page link as this forum doesnt let me paste web links even though the tool let you select the code for it.

What a lazy bunch of site admin group,
to not have this sorted or even allowed.
 
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#24
This site is down but I can post the old info here
Wow that's a late response. lol but at least it got me looking.
w*w*w.users.bigpond.net.au/Mr2/rpm/2002ktm400exc/2002ktm400exc.htm
.
2002KTM400exc .1 week old. Differences from 2001
It has been fun running it in during the week.

Ok according to the supplied parts manual the new parts are for the 400/520 SX, MX, EXC RACING
The info is for all in range unless a model is mentioned
And if it is wrong then u should be writing this for others, instead of me.

All the info was added to help people maybe improve on their bike setup and to maybe see what has been hopefully improved upon thereby highlighting possible weaknesses.


And here they are! I may have missed some or errored!
2002 updates to the KTM 400/520 range

--ENGINE CASE--
Sprocket cover racing (plastic cover) and new mounting bush
oil plug M24x3
Engine breather tube
-
--CRANKSHAFT,PISTON--
same
-
--BALANCER SHAFT--
same
-
--CYLINDER & CYLINDER HEAD--
same
-
--VALVE DRIVE--
Rocker arm intake
Rocker arm exhaust
-
--TIMING VALVE--
Between the camshaft-gear and the water pump
Washer
Gasket support
O ring
-
--LUBRICATING SYSTEM--
same
-
--CARBURETOR--
Carburetor Keihin CR39 (20 new parts many are as needed ie diff jets)
also called Vergaser Keihin SX FCR 39
jets, screws, links and engine breather tube
-
--IGNITION SYSTEM KOKUSAN 4K3A(400sx) or 4K3B(400/520)
same
-
--ELECTRIC STARTER--
same
-
--CLUTCH--
Inner clutch hub racing
4x Intermediate disc 1.4mm
Pressure bolt
6x AH screws to hold pressure cap and hub but same springs
4x Intermediate disc 1.0mm
12x driving sleeves d=8, l=31
Same 7x lining disc 1.8mm
-
--KICKSTARTER--
same
-
--TRANSMISSION 6 GEAR & 4 gear(520sx)
same
-
--TRANSMISSION II (400/520exc),(400sx mxc),(520sx)--
3x Divided needle bearing.k 22x26x10 for the idler gears
Sprocket screw and spring washer
Shaft seal ring 32x45x7
-
--SHIFTING MECHANISM--
AH screw m6x30 that mounts the shift locating drum
to the shift roller 6 speed gear(dog clutch)
-
--COOLING SYSTEM--
MXC only has a bush, roller and screw for spoiler and tank
-
--SPECIAL TOOLS--
And this doesnt make much sense to me but
a new Piston ring compressor D=75mm ???
and the other 2 of 89mm and 95 are there as ususal.?
-
*
*
*
GOD I NEED A BREAK!! I HOPE YOU ALL APPRECIATE THIS ?
*
*
*NOW FOR THE FRAME/CHASSIS* This will be less detailed
-
--FRONT FORK WHITE POWER USD--
i don't know what was on 2001 but for 2002
Front Rebound Dampening knob on top
-REAR-
My manual says WP-5018 PDS on rear and the
SX has High Speed compression adj, but not on EXC
The SX has Spring PDS7-260, EXC PDS6-260
ie exc softer than sx
-FRONT-
400/520 SX WhitePower 48mm WP-4860-MXMA and new bottom
tripple clamp and axle about 30 different bits(size)
-
400/530 EXC WhitePower 43mm WP-4357-MXMA
-
--HANDLEBAR, CONTROLS--
fuel hose 7x2mm ???
glue ??? on throttle maybe??
SX short circuit button
as usual, comes with 2 mirrors and the mirror comes with a bracket
that can be used if you break the original bracket clamp.
-
--FRAME-SUBFRAME--
SX silver sx racing footpegs
SX instead of chain roller a sliding piece is used
-
--SIDE STAND--
Side stand screw
Side stand bracket
aus/eu version has the small bracket and 2nd spring
-
--SWINGARM, CHAIN GUARD--
same
-
--REAR BRAKE CONTROL--
self-locking nut & washer for pivot bolt
-
--EXHAUST TUBE--
same
-
--EXHAUST MUFFLER--
All new
SX silencer 595.05.079.200
EXC 400 unthrottled 595.05.081.100 is avail
EXC 520 unthrottled 595.05.081.300 is avail
EXC 400 throttled 595.05.081.000
EXC 520 throttled 595.05.081.400
MXC EXC RACING USA 250-520 sparky 595.05.082.200
EXC 400 end cap unthrottled 595.05.081.150 is avail
EXC 400 end cap throttled 30mm 595.05.081.050
there are more but these are the NEW ones
-
--AIR FILTER BOX--
same
-
--TANK SEAT COVER--
gasket for filler cap high
SX seat 125/250/380sx
SX seat cover
Side covers black
EXC washer for tank roller
-
--MASK, FENDERS--
Black rear fender
All new decal sets (front and rear) sides
-
--FRONT WHEEL & BRAKES--
SX 20mm axle & nut for 48mm forks
-
--REAR WHEEL & BRAKE--
Bearing spacer 121.5mm
-
--HEADLIGHT & TAILLIGHT--
rear light locknuts & washers
-
--SPEEDOMETER--
washer for locknut only for the square USA EXC
-
--WIRING HARNESS--
same for all except horn 12V K80/L
-
--ACCESSORIES--
There are 2 new ones
Hand Guards 600.02.079.000/30 avail
Engine Protection Plastic 590.03.090.200 avail
-
-
-
-
Thankfully all that is over.
As many of you can imagine how long that took it would be
good to see some other people add to this bulletin board
to help others out.
-
www.users.bigpond.net.au/Mr2
-
-
===========================================================================
===========================================================================

Primary ratio for all is 33:76
======================

--- 400sx - 400mxc - 400exc - 520sx - 520mxc - 520exc
1 - 16:32 -- 16:32 -- 14:34 -- 16:32 -- 16:32 -- 14:34
2 - 18:30 -- 18:30 -- 17:31 -- 18:30 -- 18:30 -- 17:31
3 - 20:28 -- 20:28 -- 19:28 -- 20:28 -- 20:28 -- 19:28
4 - 22:26 -- 22:26 -- 22:26 -- 22:26 -- 22:26 -- 22:26
5 - 24:24 -- 24:24 -- 24:23 -- --N/A- -- 24:24 -- 24:23
6 - 21:18 -- 21:18 -- 26:21 -- --N/A- -- 21:18 -- 26:21

My 2002 KTM 400exc aus sprockets were dumped and replaced
with 14:52 the day I got it.
This goes well. but I am considering a 13 for the hills
thick with trees for those nervous moments.

I was also given the option of having the exhaust dismantled and internally modified but I opted to wait until after I had run it in, but I have since decided it has plenty of power for the steep hills I
attack. My problem is getting a knobbie that grips and flings enough clay out.

I could knock the guts out and I would have no probs as its a few pop rivets and no one would know I've been in, if i was booked for noise i could just pack it to the max with fibre glass intill i pass the complience test.

The Horse Power MODs i have been recommended to me
are as follows. (and they are in the AU August Dirt Action Mag)
1. OIL level, keep in window when hot
(higher severly robs power) $0au
2. AIRBOX drill holes and place mesh
in side airbox cover. $5au (Not for me)
3. Exhaust End Cap Change $140au
4. ReJet / Tune $0-100
Suggestions-Leave it as is or buy the
KTM 520 then complain there is too much power.

But thats just my opinion, and until you
can follow me where i go - I'M RIGHT {