Thanks David. I'm definitely clear on the vacuum leak front - all is nice and snug with no sucking. You advice confuses me a bit though. I thought if you had a slow decent back to idle it indicated a bit of a lean run-on.

I am not questioning you, just trying to understand. I tested it out and when I went half a turn out she died, but half a turn in it was fairly similar with high revs for several seconds, followed by the bike eventually slowing till it died.

I also tried to put the needle clip down 1 slot (so raised the needle 1 slot), but when I hold the throttle open about a quarter the bike seems to be bogging a bit. So I need to drop the needle again I think.

LOL. Coz she isn't dialed in yet I haven't tried to do much "performance testing". The direct slide carb certainly makes the bike more instantly responsive though, of that there is no doubt.

 

Now you are down to 1/4 turn at a time then One hour or 1/12 turn. FINE tune it.

I make small adjustments then ride to see how it is under normal riding conditions.

How many turns is the pilot screw now? (from all the way in)

David

 

So, it's Australia Day today so I have the day off to dedicate to trying to sort my bike out.

Riding it on Monday and Tuesday I noticed there is a thick soot in my pipe now, and when idling there is a strong smell of fuel around the bike, so am convince I was running too rich at idle. I decided to check my fuel screw setting again after chatting with a mate and realising I probably hadn't screwed it all the way in before setting it (for fear I would strip the threads). I only screwed it in till I felt decent resistance rather than till there was no more give in the spring. Silly mistake to make.

Needless to say, screwing it in properly I realised I had it set at about 4.5 turns out rather than the 1 or 2 I though I had it at. So after seating the screw properly I went to 1.5 turns out and tested. SO MUCH BETTER! I had to turn my idle down a fair bit to have it sitting on around 2000rpm, and she idles a lot better, but still suddenly dropped revs after 10-15 seconds.

I now have the screw set at just 1 turn out, and although I am not sure it is 100% correct, I am a lot happier with it. I am not really worried about it stalling anymore when idling. Now I need to spend the next couple of days riding it to see whether I need to drop a jet again and try reset my screw properly, or whether the setting I am on now is the best I will get. I am going dirt riding on Saturday, so will get to test it in anger offroad too which will be a good barometer on how close I am.

Now that I am this close, I am also debating the merits of sticking it on a dyno to get a read on the a/f mixture at different throttle positions (and also an idea of what sort of power I am developing now). Comments?

 

Only one turn out would indicate to large a pilot jet in my opinion........

Have you set it using the correct method? Correct me if I am wrong but to set correctly… run the bike up to operating temperature, then while at idle screw the fuel screw in until the idle changes (lean) then screw it out while counting the number of turns until the idle speed changes (rich).

best idle should be half way between i.e. if you screw out 3 turns and the idle changes then back it off 1.5 turns and you should be at your best idle. If you’re best idle is at 1 turn or less than full seated the jet is to rich and if it is best at 2.5 – 3 turns or greater out from seated then it is two lean.

This is how I set my TM36-68 and the idle is perfect and runs spot on. I had to play around with jet sizes to get the idle to change when screw-out though.

 

You are right Neil, my pilot jet is too rich. That frustrates me because I had the #52 in before I went to the current #55 jet. I can only assume the seal I had on the spigot adapter was allowing some air to be sucked in and make me think I was too lean. Now that I have sealed it properly and am down to 1 turn on the #55, maybe the #52 will work better? It's just too hot for me to be bothered trying today

As for the method you describe to find the ideal a/f screw setting, I know of this method but cannot do it as there is not enough space under the carb to get to the a/f screw. There isn't even enough space for one of those nice aftermarket screws . So the only option available is to make small adjustments by removing the carb, making the change, and refitting it. Painful to say the least!

Thank you for your post though.

 

Now that you have the bike running, how does the throttle respond? You are describing a too rich situation that could be the pilot jet or even the needle jet.

Pilot jet should be between 1 and 3 turns out with the bike idling PERFECT. at the correct speed with no changes. I shoot for 1250 to 1500. Also once you crack the throttle open to about 1/8 or even 1/4 the pilot jet still has an effect. The mixture screw works mostly AT idle then the pilot jet takes over. It would be worth going back to the smaller jet. If this is what you need, it will help with fuel economy too. 1/4 throttle is where we run the bikes most.

A small screw driver bit and a 1/4 wrench with some tape or something and a mirror makes it so I can adjust my carb on the bike.

You need to get the pilot jet perfect before moving on to the rest of the jetting.

David

 

Enjoyed reading all the threads...I've gone thru almost all the same issues 10 years ago on my 331....from the fcr fitment and then rideabilty to a sloppy tm36. As a noob to this forum, it's good to see people still playing with the klx. I was surprised to find that the klx can be so modded that it winds up being a totally different bike.

 

With the a/f screw at 1 turn out, even though it's probably still a bit rich, the throttle response is much better. There is no doubt the slider carb has better response, even if it's not jetted properly yet. I think my tyres are taking a bit more of a beating on the blacktop now with the FCR as they are fighting for grip a little more when accelerating out of corners. Although it is better though, the FCR has suddenly "invented" more engine power. So it's not like I am fighting to keep the front wheel down now - far from it. Doing a wheelie is still going to require a bit of tecnique rather than relying on engine brute force.

On the fuel economy side of things, I was staggered on Tuesday when I had to switch to reserve after doing just 75km's! On my CV carb I was doing closer to 110km's before needing to switch to reserve. Granted, there was a bit of fuel spillage when I kept removing the tank, and I have been giving the throttle a good workout "testing" the carb, but still. Hopefully it will improve a bit from here.

 

That sounds like terrible fuel economy even on the CVK carb….. I did 120klms last weekend (on the stock Speedo which is out by about 10% so around 108 actual klms), mostly on black-top but a little trails, we weren’t exactly going slow either…. Filled up after wards and squeezed in 4.5 litres so had about 2.3 – 3 litres left. This leads me to believe I could get around 180klms per tank.

This is on a stock bore and properly jetted TM36-68 carb. Fuel was a little better with the CVK and if I remember I think I could get around 220klms to a tank (this would be Black-top riding only though).

 

At the last enduro my klx, with an fcr, went dry at 42 miles. I was actually making a circle around the gas truck and it ran out. When I ran the 36 mik, it made it right around the same. The cvk will put up about 50 miles. My 2stroke yz250 gets a little better mileage than my fcr equipped klx.