Changing mix ratios and jetting

[dittohead]

So I just picked up a 09 ktm 300 and the previous owner was running opti 2 mixed at 100:1. Im not ok with this and will be going to amsoil interceptor at 50:1 like my last bike. I pulled the carb apart and found the following. Ill be at sea level to maybe 2000 ft tops and temps from the 30s to the 80s in coastal BC.

Bike has a gnarly pipe and q stealth silencer. Powervalve is screwed in a ways but unknown spring.

35 pilot

160 main

#7 slide

N2ZJ needle

Air screw 3/4t out.

After reading the 300 database I think the current jetting will work ok but I'm having major spooging and the bike feels lazy on the bottom. Plug is wet and black. Repacking the silencer tomorrow. Also the bike kicks extremely easily, like too easily I think. The top end has 60hrs on it. I'm coming off a fully trail prepped zy250 that I jetted myself and it ran very, clean and strong, so far I'm not in love with this bike. Hoping it does t need a top end but it feels like that is the way its going

Edited November 5, 2016 by dittohead

[Creeature]

I don't like the sound of 100:1 mix either.

Needle sounds rich go down on the clip or try one of the Suzuki needles the 300 guys run. NEDW maybe?

You shouldn't need a top end at 60 hours unless the po meant to say 260 just left the two out. I think the book calls for 2 turns out on the air screw.

Edited November 5, 2016 by Casing-daily

[kxrob]

40-42 pilot

NEDW Suzuki needle clip 2

And plug chop to work out the main

Google spanky's jetting guide for proper air screw setting

Edited November 5, 2016 by kxrob

[dittohead]

Forgot to add the clip is at the second from the top of the needle. Bigger pilot? It feels pig rich at idle with this 100:1 crap in it but your right I'm sure I'll have to fatten it up with the 50:1. I'm a slow trail rider 90% of the time but like to hit big gravel pit climbs once in awhile

[Creeature]

Less oil (100:1) is a richer fuel mixture. I'd listen to robs specs at 50:1.

[dittohead]

Less oil (100:1) is a richer fuel mixture. I'd listen to robs specs at 50:1.

Yup I know how it works, just noticed on the 300 jetting guide most people seem to use a 38 pilot, but ill order a couple different sizes so I can experiments. thanks for the help guys. Ill post up when I get the thing on 50:1 and the carb parts arrive.

[zilla]

For the non-believers, I have been running OPTI-II@100:1 in my bikes since 06.  Never a problem..

Edited November 5, 2016 by zilla

[dittohead]

I don't like the sound of 100:1 mix either.

Needle sounds rich go down on the clip or try one of the Suzuki needles the 300 guys run. NEDW maybe?

You shouldn't need a top end at 60 hours unless the po meant to say 260 just left the two out. I think the book calls for 2 turns out on the air screw.

The bike def has more like 200+ hrs on it but I had the reed block out and took a peek in the case and its squeeky clean and the piston looks new. The PO said he put in a new piston/rings 60hrs previous but didnt know the total hrs on the bike. It came with a new set of rings so I might just put them in if I can't get it to run clean

[dittohead]

For the non-believers, I have been running OPTI-II@100:1 in my bikes since 06.  Never a problem..

Really? I tried doing a search on people who ran this stuff in dirt bikes specifically and couldn't come up with much

[kxrob]

80:1 -100:1 can be done ( I don't know if I will ever try it) but only for slow trail riding , could be wrong

[zilla]

80:1 -100:1 can be done ( I don't know if I will ever try it) but only for slow trail riding , could be wrong

I raced dez nationals very sucessfully running this combo..    I found out about it from an ex Canadian ISDT rider  who has been running it since the late 70's or so..  

 

http://www.fmsq.net/nouvelles/profils-de-pilotes/168-helmut-speedy-clasen-81-years-old-and-still-grinding.html

[islandlife]

Do a compression test. As the compression lessens, the bike will seem to run richer and richer. With your jetting you should be pretty close to spot on for a fresh motor, maybe even a bit lean. If the bike seems to kick over super easy, and its low on power and spooging, i would bet money you need a fresh top end.

[dittohead]

I adjusted the air screw out another 1/4 turn and repacked the pipe and it feels much better and its not spooging but its still very easy to kick over so I'm also thinking that it's down on compression. If the weather holds out tomorrow ill take it for a actual ride and see how the power is and go from there. Feels ok doing passes down my 200ft driveway but that doesn't tell me much lol

[kxrob]

To set air screw correctly bike has to be warmed up completely , did you set air screw it for the highest/fastest idle ?

[dittohead]

To set air screw correctly bike has to be warmed up completely , did you set air screw it for the highest/fastest idle ?

I had it warmed up. Its got a less Blubbery sounding idle that is slightly higher rpm then before. I'm happy with where it's at now.

I got out for my first ride with it yesterday and I'm thoroughly impressed. This is hands down the easiest to ride bike I've ever ridden. I was sweating using the Manual clutch since I havent ridden a bike without a rekluse in years. This thing is nearly impossible to stall and the clutch is a one finger operation, it was like cheating compared to my yz250. The jetting in the bike now on the 100:1 works great but I'm getting a lot of blue smoke but only about a 1" long trail of spooge on the silencer after 2 hrs of riding mainly 2nd/3rd gear trails. Ill be making the switch to 50:1 in the upcoming weeks but I need to do a compression check then move on from there. The bike still feels very strong but totally manageable.

Edited November 8, 2016 by dittohead

[tcmII]

I know it's been a while since anyone posted here, but my 2 cents.  SlavensRacing.com has some information on running the amsoil at 100:1 and it seems a lot of people do it.  As far as going from 100:1 to 50:1, you already know that under normal conditions you would be leaner by the math (50%).  For the '08 300 KTM Manual says 60:1.  I run 64:1 because it's easy at the pump (2 Oz. to 1 Gal.) .  My current jetting is: 165 Main, 38 Pilot, N2ZJ on #2, AS about 1 out, about 1000ft, 40 - 80' F (Oh about 90 hours on top end).  I've only owned this bike for a few months, but so far it's been fine and I have no spooging at all.  The original owner said that's the jetting since he bought it new. (not stock)

[sbest]

Forget the new parts for now and try a switch to 50:1 Amsoil Interceptor like you planned.

IslandLife has it pegged that low compression gives the impression of overly rich jetting. 

More oil will help to seal it up, see what changes. 

 

Your 160 jet seems lean to me (I have a 2001). I don't run that even in the summer. 

Set your main by plug chops, not internet advice. 

My 2001 runs crisp and clean with 50:1 on Interceptor, Motul 800 and Ipone "strawberry". 

It still has the original piston in it and well over 250 hours on it. 

 

I ran one of my 125s on 90psi compression forever. It had swallowed dirty water and scuffed the cylinder. 

I could start it by hand  and lost some off idle torque but still had fine top end power. 

Switching from 50:1 injector oil to 40:1 premix really helped starting, idle and low end torque until I replaced the rings. 

 

Steve

Edited November 13, 2016 by sbest

[tcmII]

With mix at 100:1 the 160 main may ok.(not a jetting expert) I run at 165 main with mix at 60-64:1 (complete settings in previous reply).  The original owner told me those are teh specs he ran since new.

[sbest]

With mix at 100:1 the 160 main may ok.(not a jetting expert) I run at 165 main with mix at 60-64:1 (complete settings in previous reply).  The original owner told me those are teh specs he ran since new.

Jetting change is negligible between 50:1 vs 100:1

100:1 is great for indoor and stadium events or trail riding where you don't want to smoke out your buddies. 

Nikasil is tough stuff and chrome rings can take a lot but the bearings still need some oil. I'm not convinced. 

I still feel brave when I run 50:1 and feel safe at 40:1. 

 

Steve