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I finally found the time to get my bike back together and took it out in the rain for a few hours which I feel is so underrated, especially in the wood, tons of fun…. I am running the rb carb with Rons baseline settings. 40 pilot, cek/dek needle 3rd clip (to be honest I forget which one I put in). I’m seeing a good amount fairly thick light blue smoke above 1/4 throttle. There are some hiccups off idle idle especially after short shifting around. If I’m not consuming any trans fluid, I may need to go down on the needle and main check. I may check the jet block gasket because I had it apart and reused it, it had a handful of hours when I did so. I will be rechecking the sight glass tonight once it settles on the stand to confirm that there isn’t any trans fluid consumption. The leak down test result was excellent after addressing a few air leaks so I’m doubting the trans loss but I’ll still check again.

Ok I just put a new one in again. Coincidentally I had received one within a kit on Amazon recently. If not I am going to have to lean things out. Don’t see a loss of trans oil. If it’s not the jet block or jetting, I think I will have narrowed it down to rings. But I would be very confused why the rings have prematurely lost their seal with so few engine hours. I’ll get to that. And if I do get to that point then why would the rings be failing so quickly? I feel I should be real close with the jetting already.

It could just be the clip position. If mine is one clip too rich it’ll smoke over 1/4 throttle. Too rich on the needle will also cause hiccups after cruising around. The clip position is a quick 5 minute swap. Try 3, 2 and 1 and take it for short rides rolling on the throttle. The correct one should be very obvious.

John_S wrote: 09:07 am May 21 2023 It could just be the clip position. If mine is one clip too rich it’ll smoke over 1/4 throttle. Too rich on the needle will also cause hiccups after cruising around. The clip position is a quick 5 minute swap. Try 3, 2 and 1 and take it for short rides rolling on the throttle. The correct one should be very obvious.

I went to 2 and it cleared a lot of hesitation. Still lots of smoke and slightly blubbery and less responsive when mashing the gas or going 1/2 to full throttle. It’s only smoking when I decide to push it harder. For example I’m trail riding for awhile and coming to a field and banging through the gears. When I look behind me I can see lots of smoke. I’m jetting based off feel and alittle worried that going down to the 145-148 main will be too little. Maybe the porting has added a lot more velocity through the carb and I’m sucking down too much fuel. Still having fun out there but definitely not gonna stop here. Also here’s a pic of the fender, and end cap. (Yes I know I need to drill it out and reseal with new rivets.) Thanks !

I also pulled the plug with about 3 hours on it and it wasn’t looking great. I’m so confused, I really don’t understand this situation. Ron’s baselines settings should be close but I keep seeing this ugly spark plug. Leak down test was great, carbs sealed up nicely. What the heck. I’m gonna order a coolant temp cap and take it out for a ride when I find the chance.

What's your float height set at? Are you loosing any transmission oil?

SS109 wrote: 06:59 am May 22 2023 What's your float height set at? Are you loosing any transmission oil?

I set it for 16-17mm. Also I don’t think the transmission oil level is changing. I have it on the stand and it’s still a hair above the window.

Try setting your float to 18mm. I have found on every KDX I've owned that the stock float height is too high and makes them run rich.

SS109 wrote: 08:14 am May 22 2023 Try setting your float to 18mm. I have found on every KDX I've owned that the stock float height is too high and makes them run rich.

I’ll give that a shot. The plugs looks like it’s getting real hot but I don’t see a problem with running the br8es. My 1991 looks and runs perfect with 4 hours. And it shows. Nice mocha color gradually getting dark toward the base. I can’t say the same about the 220. Look at this plug though. Couldn’t get it to focus

IIRC RBs baseline is for a stock KDX with the modded carb. Change pipes, reeds, porting, etc will require changes away from the baseline. The only reliable way I've ever had results with is the published jetting method you can find on here. Change one thing at a time, and do the pulg chops. Yes it sucks, Yes its boring, Yes it works.

With your #40 pilot jet, how many turns out is your highest idle? Like Bufftester said, it's time to follow the jetting guide.

Molly's 70 wrote: 05:00 pm May 22 2023 With your #40 pilot jet, how many turns out is your highest idle? Like Bufftester said, it's time to follow the jetting guide.

I will go through the process. I have followed the jetting guid in the past but I copped out on doing a plug chop

I tried my best to follow the jetting guide the past hour. Started with pilot jet. Follow the procedure to a t. I ended up around 3 turns out with the fast idle with a 40 pilot. I went to a 38 pilot and was still around the same area. Basically the further I turned the air screw out the higher the idle would get. I then attempted to fine tune it but I couldn’t get a good feel. I really think the porting has robbed alot of off idle response. I then went back to the needle on the throes groove. Went from 1/4 to 3/4 throttle several times and it didn’t hesitate but didn’t sound right and was still blowing smoke from part throttle to full. I got fed up and skipped straight to the plug chop. I wasn’t even able to fully rev through 6th as the bike started to feel off like it was losing power when going through the gears and being that hard on the gas the whole time. That’s where I am at. I still looked at the plug and this is it but I’m talking on 250 -300 feet of full throttle

From what I know engine power increases with cylinder pressure. So porting adds power therefore there is an increase of cylinder pressure due to more air being compressed. With the RB head which I requested to be safe on 93 octane and later on I went forward with Jeff Fredettes porting, is there a chance it’s just too much? I read an old post about someone suspecting too much squish on a different 2 stroke engine. “ Theory: too much squish space is leaving fuel/air laying around where the flame front doesnt propagate well, leads to rich bottom end and finiky decel pinging/ low load knocking due to remaining fuel lighting off later in stroke.” -https://dirtrider.net/forums3/threads/h ... 237/?amp=1

I have the RB carb & head with Fredette porting. Best running bike I ever had. Keep working it.

Molly's 70 wrote: 03:03 am May 23 2023 I have the RB carb & head with Fredette porting. Best running bike I ever had. Keep working it.

I don’t know what’s with the bike bogging while going through the gears for a plug chop. It just seemed to hate that and felt even worse when doing. I the smoke says to go leaner but the plug and the bogging during the plug test says otherwise. What a pain in the butt. I want to take a look at the top of the piston and see if that can give me any ideas then continue on with jetting.

If your leak down test & compression test are good move on. I don't know what fuel/oil ratio you are using & it shouldn't matter if jetted close.

For example, I am using VP VPR fuel w/ Amsoil Dominator 50:1 oil. 38 pilot, CEK middle position, 152 main.

FMF pipe has been Jet Hot coated to look stock. Airbox lid removed. I could probably go down to a 150 on the main jet, but I haven't... yet.

I’ll keep going with it. There is still a part of me that thinks something else is going on. I had no issue getting the 91 jetted nearly perfect. I’m making myself sound like a turd with all these posts about this 220. It really wasn’t until I got the porting done that I started experiencing this kind of trouble with the engine. I am envious that you’re able to have such success with jetting, Slick Nick also as you both have the same/similar mods done.

Never try to jet by the amount of smoke you see. Only go by what the bike is telling you by how it runs and doing plug chops.