ktm 125 and 250
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ktm 85 sx

Chesterfield, UK

#62 Apr 27, 2009
hi mate u have to blead the ktm cluch back 2 fnt usea sringe to do it
ktm 85 sx

Chesterfield, UK

#63 Apr 27, 2009
what is the best ger box oil to use on a ktm sx 85

West Chester, OH

#64 May 5, 2009
I have a 2000 KTM 125sx with a mugura hydrolic clutch, i refilled it with straight mineral oil like it says but my clutch will still not engage and im pretty sure its what is causing my bike to bog down once i do get it going? can anyone help?

Nottingham, UK

#65 May 25, 2009
can anyone help ive mixed my petrol/oil at 100ml to 5 litre's in my son's ktm85 and it still smoke's anyone know what this could be ?????????

Elanora Heights, Australia

#66 Jul 16, 2009
bike boy wrote:
<quoted text>
Umm just bought one and im positive its 40:1
Yep - 40:1. Instruction manual gives this ratio.

I know people who have run even leaner on 50:1 but I would be reluctant personally to do this for a prolonged period.

BTW - 32:1 is more oil than 40:1!!

Elanora Heights, Australia

#67 Jul 16, 2009
bananasplits1970 wrote:
can anyone help ive mixed my petrol/oil at 100ml to 5 litre's in my son's ktm85 and it still smoke's anyone know what this could be ?????????
My son's bike does exactly the same and he rides it hard. Have had it checked out and it just happens that he has a smokey bike! There is no problem with it...but I would be using a 40:1 ratio not 50:1 - it's still going to smoke however lean you run it but there is less risk of engine wear with the recommended oil ratio.
You could also try repacking the silencer - this could help marginally with smoke and noise.

Woodbridge, VA

#68 Aug 8, 2009
Hi i was just wondering what kind of engine oil to put into my 04 ktm 125 thanks

Since: Aug 09

Flower Mound, TX

#69 Aug 29, 2009
I own a 125sx 2003, i was just curious what the small hole in the bottom of the crank case is for. It's located on the left side of the case right where the crank case splits. I notice there is a lot of oil build up in my skid plate and around the bottom end.

Winder, GA

#70 Oct 28, 2009
dustin wrote:
i would like some recamendation on wich is better 205 ofur stroke or 125 two stroke
.i mix my oil at 32 to 1
rhys ktm sx

Portsmouth, UK

#71 Aug 6, 2010
y is that my crank is full of the water from the rad & how can i clean it out for cheep thanks

Braintree, UK

#72 Aug 25, 2011
iawn bois just bought a ktm 125sx 2003/04 is the clutch system hydraulic on them ie the leaver hydraulic assisted thanks


#73 Mar 6, 2012
So just out of curiosity could u use a 20W50 oil for a ktm 125 exc?

Placentia, CA

#74 Mar 14, 2012
I own an 08 Sx 125 and my owners manuel says to run 40:1.


#75 Jun 10, 2012
Since I bought my ktm 125exc a month ago , when putting in 4 litres of fuel only been adding 40 mm of castrol tts oil, I now know this is not the recommend amount , just been worrying about it , the bike has been running fine though , how much damage do you think has been caused ?
Ktm 50

Chalfont, PA

#76 Jun 21, 2013
I purchased a 2006 ktm 50 mini adventure and found the exhaust port off the cylinder was clogged with crusted oil and was leaking badly. After replacing the piston ring and gaskets i found my exhaust system was also completely obstructed. I' e never seen such a thing. Any idea what could cause this? How can i clear it? Any chemical or fluid to break down the hardened oil?? Thanks
ian donoghue

Hetton Le Hole, UK

#77 Jan 30, 2015
I have a breather hole on right hand side of my 1999 ktm exc what is it for

Dewsbury, UK

#78 Jan 26, 2016
Jon Wright wrote:
<quoted text>
Gday mite !
Thanks for your request - hope I can help.
Ok- I cant see the bike myself (Oz?- I wish!)so i'll try and describe the problem first, but if its a different prob, just mail back and correct me -
Ok -
- There is 100% no drive at the wheel, i.e. you run the engine put it in any gear (not just 1st gear) and let the clutch out and you can stop the back wheel with the brake without stalling the engine.
(dont do it too much- you'll make the damage worse!)
I assume you were riding it one day and it just went?(could be a different reason if it was rebuilt then it didn't work)
OK - look at the countershaft sprocket first just in case (I'm sure you already did this)- Is it worn round and smooth? Take it off - are the splines on the sprocket and output shaft in good order?
So - delve deeper - There are quite a few posibilities (list at end), but my first instinct is the primary drive gear on the RHS of the crankshaft. Its held on with a woodruff key (a little half moon bit of metal). If the nut holding it on loosens a bit, it can move around enough to shear the key (especially on a 125 where you feather the clutch a lot to drive out of turns). The engine would run perfectly but transmit no drive to the gearbox.
So - take the full LHS casing off (OK engine in frame)and take off the nut that holds the gear onto the crankshaft.
Its tight so I normally use a wedge of pine between the primary gear (on the crank) and the clutch ring gear, but that wont work if its sheared so if its still tight you might have to take the barrel and piston off, make a nice flat block of wood that fits over the crankcase mouth (leave a gasket on it to avoid damage), and put other blocks either side of the con rod running front to rear that the gudgeon pin can bear on when you turn the nut - sounds complicated but is really easy.
Take the nut and gear off - if its the woodruff key it will be obvious - chopped and smeared. Clean the keyway up - if its not damaged (widened and uneven) count your lucky stars, chuck in a new key, tension the nut up correctly and you're back in business. If its burred, you can put a new crank in or have it built back up with weld but do not be tempted to weld the key in, or the gear to the shaft - it wont last two minutes and then you wont be able to get the crank out of the casing !
Anyway - I spent a lot of words on that - if its not that, check the rivets that hold the clutch gear to the back of the clutch basket, and also that there are enough clutch plates in. Also check that its really going into gear - if one of the pins that hold the selector forks snaps, it will click up and down but not really go into gear.
Good luck - let me know what it was when you find it.
Jon Wright
hi jon are you still on here i really need some advise

Dewsbury, UK

#79 Jan 26, 2016
Jon Wright wrote:
<quoted text>
No problem mate - hope it helped. As its not oil getting into the combustion side, even if it is the water pump seal its a cheap / easy fix.- if it is that, my advice is - fix it yourself with a genuine seal, but dont use plain water or cheapo antifreeze as the aluminium and magnesium parts dont like it - use lots of good bike specific antifreeze and you'll never have to buy a new casing -
One more thing... to everyone - enjoy your MX - lifes too short not to !
Jon Wright
are you still on here jon need your help cheers

Dewsbury, UK

#80 Jan 26, 2016
any body any idea how to set the ignition timing on a 1995 ktm 125 sx i know its quite old but its a project thats driving me mad, cheers

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