125 Gargiling

Ktm125sx · 09-28-2009, 04:53 AM

Hi, i have a 2003 ktm 125sx, and as far as i know it has never had an engine rebuild, the engine sounds solid and has no strange rattles, the only problem is if i drive at a constant speed it sounds like its gargling, and if i rev it in neutral at a constant rpm it sounds if it missfires violently, but when its under load it sounds great eg accelerating or going up steep hills, what is it !?

bajadog · 09-28-2009, 07:51 AM

Reed valve?

Ktm125sx · 09-28-2009, 06:27 PM

i hope its not the reed valves as they are new carbon vforce reeds.

richie_450 · 09-30-2009, 03:36 AM

when your going at constant speed and it starts doing this is there a slight loss in power or it feels like its not pulling anymore? if so your bike is running too lean and you will sieze the piston and its not just caused by incorrect fuel mix ratios you may have an air leak somewhere. if not clean your carby out jets ect when you do that as said before check the reed block if you have small chips in the corners of the reeds you need to replace them i paid about $85us for mine.

richie_450 · 09-30-2009, 03:40 AM

lol hang on your not talking about when you just start the bike are ya? or just putting along slowly because they do that

bajadog · 09-30-2009, 07:15 AM

Just to verify what Richie was asking.

Are you talking about at warm up?

Also when it's gargling, is it smoking?

Ktm125sx · 09-30-2009, 08:16 PM

no i never rev my bike when cold, i only drive it when warm, and i only go top speed when its hot, because the piston heats up alot faster than the head,
and yes it garggles only when im going along at a steady speed, and it smokes but only a little bit, like all 2 strokes

, smokes a whole lot when cold tho.
there is no loss of power its still all there ready to go, its just it sounds so unhealthy when i go along gently, only sounds good when i abuse it :S

bajadog · 09-30-2009, 08:51 PM

If pull the plug, and kick it through with no binding, scraping or grinding, then
you know it's not the jug, or piston.

It really sounds like ritchie mentioned, carburation, vacuum leak or reeds.

Just for sh*ts and giggles what are you mixing oil gas to ? 50:1?

Ktm125sx · 09-30-2009, 08:56 PM

yeh i use 50:1 but i only use high performance 2 stroke oil, not mower oil

and it might be an air leak because were the carb mounts to the engine is a big rubber mount which has aged and has big cracks in it but im not sure if its still sealed, also the bike spits out a fair amount of black crap out the exhaust, its like a really thick liquid is that bad ?

bajadog · 10-01-2009, 08:29 AM

Quote:

Originally Posted by Ktm125sx

is a big rubber mount which has aged and has big cracks in it but im not sure if its still sealed, also the bike spits out a fair amount of black crap out the exhaust, its like a really thick liquid is that bad ?

Start up the bike, and spray a little carb cleaner or WD40 around the cracked
big rubber mount. If the RPMs pick up, then you have major vacuum leak, and you need to replace that boot.

It also sounds like you are not burning all your oil in the gas. This could be from the vacuum leak, or the spark plug heat range being off, or to rich of a main jet in the carbie.