OzVMX Forum

Clubroom => Tech Talk => Topic started by: gra1961 on January 21, 2011, 08:04:12 am

Title: ktm600 rotax 4 stroke
Post by: gra1961 on January 21, 2011, 08:04:12 am
ive just got my 84 ktm600 4 stroke rotax going but to get it to idle the idle screw has to be turned in all the way and have the choke on a little bit other wise it pops a little at the exhaust.bike starts easily and runs clean like this.im thinking maybe cam timing?any clues.(easier to post this than to go down stairs and check it out)
Title: Re: ktm600 rotax 4 stroke
Post by: evo550 on January 21, 2011, 08:35:32 am
Sounds like it's running lean, checked for air leaks? changed the jetting?, fitted a different exhaust?
Title: Re: ktm600 rotax 4 stroke
Post by: LWC82PE on January 21, 2011, 08:49:27 am
Air leak between carby and cylinder or there is a blockage in the carby somewhere. I had this problem on a kawasaki quad once, the bike would not run without choke. Took the carby apart, blew it out and then it was fine.
Title: Re: ktm600 rotax 4 stroke
Post by: Slakewell on January 21, 2011, 09:32:15 am
You need the correct cam belt on these , there is a new one thats 1/2 a tooth out and gives problems.
Did you replace the belt?
Title: Re: ktm600 rotax 4 stroke
Post by: mustanggrahame on January 21, 2011, 12:18:00 pm
My TT600 had the same symptoms. It hadn't been running for 4 years and even though I had dismantled the carbys, I had to do it again and really clean the pilot jetting and tube with a sharp needle. The tube had green crusty stuff in it. Worked perfectly after that. This maybe your problem
Cheers, Grahame
Title: Re: ktm600 rotax 4 stroke
Post by: LWC82PE on January 21, 2011, 12:58:51 pm
Yeah if the bike has not been running for years, there is bound to be blockages in the carby jets and orifices due to stale fuel. Old fuel causes heaps of problems these days, especially premium because it goes stale pretty quickly. You really gotta be riding the bike almost once a week so the fuel doesnt go off in the bowl. It can actually grows a green algy stuff. I will never forget the time i stripped a set of XS750 carbs and they were full of a dark green algy growing inside them, it looked like the stuff you would see in a creek or fish pond. It was really really bad and smelt really strong and bad and the smell hung around for a few days. That was the worst one i had ever come across. Before Xmas i put a new head gasket on a Trident which had not been ridden for several months because of the head leak. Well after fixing that, the bike would not run on the middle cylinder so when i took the carbies off the middle one was all blocked up with some sort of white stuff from fuel that had gone off. Before that it was gutless and seemed to only do about 80km's but after cleaning it out it was much more like the rocket it should be like and was so much better when runnning on 3 cylinders.
Title: Re: ktm600 rotax 4 stroke
Post by: gra1961 on January 21, 2011, 02:16:09 pm
have fitted a new timing belt that i got from bert floods,might clean the carby again with my glasses on this time and less beers.thanks for your input fellas
Title: Re: ktm600 rotax 4 stroke
Post by: Canam370 on January 21, 2011, 04:21:47 pm
Alright, I'll tell you the secret. That green-hard residue can't be removed unless scraped off. Solvents, nothing. But, if you put the jets etc in boiling water it will remove it or at worst soften it some to make removal a LOT easier. Makes the experience a bit nicer. ;)
Title: Re: ktm600 rotax 4 stroke
Post by: supermotomc on January 26, 2017, 12:44:30 pm
if you do read this dump the lot in LEED lemonade and leave it for two day then smile and wipe!!
Title: Re: ktm600 rotax 4 stroke
Post by: 80-85 husky on January 26, 2017, 02:11:53 pm
if sugary acid dissolves it ...ethanol residues? I had a dr 350 that had cement in the pilot, totally unmoveable
Title: Re: ktm600 rotax 4 stroke
Post by: Tim754 on January 26, 2017, 09:52:19 pm
 "I had a dr 350 that had cement in the pilot"   Could be a story there................ :o
Title: Re: ktm600 rotax 4 stroke
Post by: gra1961 on January 27, 2017, 07:51:56 am
gee that was along time ago,it ended up being a crack in the inlet manifold rubber sucking air.
Title: Re: ktm600 rotax 4 stroke
Post by: 80-85 husky on January 27, 2017, 08:18:55 am
cement in the pilot? hmm, wonder where the jet went??
Title: Re: ktm600 rotax 4 stroke
Post by: Mick D on January 27, 2017, 10:49:02 am
cement in the pilot? hmm, wonder where the jet went??

(http://i677.photobucket.com/albums/vv132/mc125mick/lost1lg_zpsvhrlgdem.jpg~original) (http://www.imdb.com/title/tt0411008/)
Title: Re: ktm600 rotax 4 stroke
Post by: KTM47 on January 27, 2017, 01:14:53 pm
If leeds lemonaide cleans it coke a cola probably will too.  have you seen what it does to a two cent coin.