'95 EXC-standard jetting-conflicting specs

jaluka21 · Mar 29, 2004

Could someone please confirm the standard jets on a 95 ktm exc? I have terrible plug fouling and suspect the jetting. It currently has a 185 main, idling jet a 48 and a NOZH(N02H?) needle with the clip in position 2 from the top. Air screw is at 2.5 turns out! My carb is a Keihin PWK 9 KTBC 1J.

I have found conflicting evidence on the site ktminfo.com where they list the standard carb for that bike to be a Keihin PWK 39 with a different(N85D) needle :think: , are these the same carbs/needles?

The bike came with no info from the seller, I am now running 40:1 mix after trying 50:1. The plug is wet and oily and the pipe is spoogy, I assume this to be an over-rich mixture. I wish to start jetting from standard but would like to be assured of the correct values. Also, are the following true?

1.Needle clip moved up= leaner
2.Main jet no. reduced = leaner
3.Going from 50:1 to 40:1 = leaner (less spooge)
4.Air screw turned out = leaner fuel/air ratio

This bike has fresh fuel, new muffler packing, clean and correctly oiled air filter and a BR8ECM plug. Is this the correct plug even? The bike is ridden near London so GB or European spec I presume.

Any help will be much appreciated. Thank you.

TM-Frank · Mar 29, 2004

jaluka21 said:
...My carb is a Keihin PWK 9 KTBC 1J....

...conflicting evidence...Keihin PWK 39...

That is very probably the same. What you wrote down is probably just a serial number or so. Go to www.sudco.com and have a look at the carb diagrams and try to find out what you have. The models in question could be the PJ (older model - easy to recognize because there the choke knob also works as the idle adjuster) or more probably the PWK. PWM is a rather new model.

The N85D needle is leaner than NOZD, mostly at quarter throttle. Both are triple taper needles and I got the tip from JD jetting to replace the NOZ series with a single taper CCK or DDK (available from Sudco too). Brought really good results.

1.Needle clip moved up= leaner Yes

2.Main jet no. reduced = leaner Yes

3.Going from 50:1 to 40:1 = leaner (less spooge) Yes, but I'm not sure if you'll notice that much of a difference between 1:40 and 1:50.

4.Air screw turned out = leaner fuel/air ratio Yes but this screw only has an effect at idle. As soon as you open the throttle it plays no role anymore.

jaluka21 · Mar 29, 2004

Thank you indeed for all the useful information, this is a really helpful and friendly website! Frank, in what respect would the CCK or DDK needle improve 'results' over a NOZ needle, or over the standard N85D needle? Thanks.

TM-Frank · Mar 29, 2004

My problem was as follows:
I have a TM300 with N1E-series needles. The N1E... is the same as the NOZ... that you currently have, only a half clip position richer. So a NOZH on Pos.3 would be the same as a N1EH on 3.5 (info from JD, too)
I did have an OK setup for pump fuel but then bought C12 race fuel and then the nightmare began. I had to install a 35 pilot jet (smallest available), the thickest of these N1E../NOZ.. needles and a pretty small main jet (162) and the bike was still running slightly rich with a bit of bogging at the start of throttle way and a lot of black spooge. That was in winter with temps below 0°C, so I had no more options for later in the year when temperatures will rise.
After I installed the CCK that JD recommended I was able to run a 42 pilot and a 172 main, so I have enough "flesh" to lean out when summer comes. Also the bike runs very clean now, no bogs, no sputtering, nearly no spooge (only after extended low rpm woods riding).
So I think it might be worth a try for you, too. It wasn't extremely expensive too. I paid 6,- € for the needle at the German Keihin importer (who gets the stuff from Sudco).

jaluka21 · Mar 29, 2004

I will try the CCK, thank you for all your help. Cherio!

supermike · Mar 30, 2004

do you have compression? bad rings???

'95 EXC-standard jetting-conflicting specs

jaluka21

TM-Frank

jaluka21

TM-Frank

jaluka21

supermike

Similar Topics

Privacy & Transparency

Privacy & Transparency