how hard is servicing a 520sx?

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#1
caught a quote in a mag that said changing the oil in a 520 was difficult. any one care to comment on that?
 
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#2
Hvyw8t
It can't be any harder than my 2001 520EXC and it's simple. There's some confusion on this topic depending on who you talk to. I don't have any special wrenching skills and have not encountered any problems changing my own oil. It's not like changing the oil on my Maico with only one drain plug. You have two filters, a drain plug and two screens to take care of.

You start with your bike upright, then it's on it's side and then upright again. There is also some talk about the necessity of cleaning all these items each time you do an oil change. I have stainless steel filters so it's easy to clean them out each time.

I followed the guidelines in the owners manual. In the August 2001 issue of Dirt Bike,pages 68/69, it's covered again in words and pictures anyone can understand.

Take your time and DON'T OVERTIGHTEN the bolts holding the special screens on the bottom and side of the motor. Don't be in a hurry and you will be fine. :cool:
 
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#3
I have found a few little problems.

1. Don't sit with your feet near the back wheel. When you pull the plug out, the oil spurts out quickly. That got oil all over my new runners:(

2. You need a allen key to get the oil screen out fom under the engine. It was not included in the KTM tool kit.

3. The oil screen bolt near the gear lever was so tight, I had to make up swear words to get it off!

Other than that, piece of cake!
 

HiG4s

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#4
You have to tip the bike in it's side? I don't think I'd like that. Is the 400 the same way? The KTM 400 is one of the bikes I'm considering for my next bike. With all the other stuff in my garage there isn't room to lay a bike down.
 
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#5
It's not a bad as it sounds:D

You need to tip the bike to the right side to put the filters back in...part of the process is filling the cases, where the filters go, half full of oil, you need the bike tipped to do this. I've got a rubber mat that I lay the bike on...no big deal. Funny, if you walk throught the pits at a Pro race...like Supercross, you see the Tech's with bikes on there sides all the time...I was horrified the first time now it's no big deal:)

And to answer your question, yes the 400 is the same. All the RFS bikes SX, EXC and MXC(400 or 520) use the same basic engine and the filters are the same.
 
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May 24, 2001
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#6
Service is more than oil changes. Consider this:
Valve adjustments on DOHC bikes generally require you to remove the cams (shim under bucket like KLX and I think YZF) even though getting the feeler gauge under the tappets on a RFS could be easier, It is still loads easier than taking the cams out then going to a dealer for a shim and finally putting them in again.
 

HiG4s

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#7
Originally posted by JEFF SAND
Service is more than oil changes. Consider this:
Valve adjustments on DOHC bikes generally require you to remove the cams (shim under bucket like KLX and I think YZF) even though getting the feeler gauge under the tappets on a RFS could be easier, It is still loads easier than taking the cams out then going to a dealer for a shim and finally putting them in again.
Take the cams out???? Street bikes have been using the shim and bucket system since the early 80s and I've never removed a cam to change shims on either my 82 Yamaha 750 or my 88 Kawasaki 750. I have not worked on a dirt 4-stroke that had the shim and bucket, you sure there is no way change shims without removing the cams.
 
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#8
Cams out

The only DOHC dirt bike I have owned was a KLX and YES you have to take the cams out (above their bearings) to replace the shims.
 
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#9
Originally posted by HiG4s


Take the cams out???? Street bikes have been using the shim and bucket system since the early 80s and I've never removed a cam to change shims on either my 82 Yamaha 750 or my 88 Kawasaki 750. I have not worked on a dirt 4-stroke that had the shim and bucket, you sure there is no way change shims without removing the cams.
You got lucky and have shim over bucket adjustment, where as most new biles use shim under bucket. Pretty hard to get shims out from under the buckets with the cams in place.
 
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#10
HiG4s,
Most modern 4 stroke motorcycles are using shim under bucket systems where the cam lobes ride directly on the valve. This eliminates a rocker arm and it's recipricating mass. The downside is that the cam has to come out in order to get the "bucket" off and gain access to the shim.

As Jeff said, service work will include more than just changing oil. Adjusting the valves is a real pain at first but you will become better at it as you do it. Unless you take off one (or both radiators), there is very little room to work with when checking the exhaust valves on the KTMs. I figured out a way to do it with out draining the coolant and removing the rads, but the first time around I was throwing out all kinds of "colorful adjectives". I've owned both a YZF (with shim adjustments) and now the KTM (with adjustable tappets) and they both have their drawbacks when it comes to service. It's a little more work to do the YZF, but they seem to stay in spec much better than my 400sx. Perhaps I have a problem with my motor, but I'm always adjusting the valves on my RFS. On my YZF, I went a full season and didn't need any adjustments.