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Jetting?

Posted: 07:51 pm May 23 2011
by rbates9
I had my carb done over the winter and have had a hard time getting the jetting to stay consistent. It seems that one day to the next needs playing with to get it to run good. I have checked for leaks and what not, the only leak I have is the air screw seems to get damp.
I have heard that the RB'D carb gets jetted "differently" than a stock carb. What is meant by that???
I keep checking the plug and it seems to stay dark even with leaner jetting?

Any thoughts?

After some screwing with it it rips, but I'm not looking forward to a test and tune with jetting before each ride.

Posted: 02:17 pm Jun 18 2011
by Brian
I had my head and carb RB'd over a year and a half ago and although I love it I've had trouble getting the jetting just right. Mostly I am having trouble getting it to run clean an very small throttle openings. Anything over 1/4 throttle and it pulls clean. I also installed the 607 reeds and I wonder if some of the poor running with the throttle just barely open is from them. I just went to a 35 pilot and adjusted the fuel level in the float bowl. I rode it around the yard and it feels a lilttle better just off idle but a real trail ride will let me know if that fixed it. BTW my riding elevation is about 1000 ft.

Posted: 05:15 pm Jun 18 2011
by Mr. Wibbens
Only adjusting I ever do is with the air screw, just to get the SSS at it's best spot

It's usually only a c*nt hair of movement though

How many turns out are you on the air screw?

I'm usually 2.5 - 2.75

Posted: 09:04 pm Jun 18 2011
by rbates9
I would have to check but I think around 1 to 1.5. I will check in the morning.

Re: Jetting?

Posted: 09:42 pm Jun 18 2011
by TWMOODY
>|<>QBB<
rbates9 wrote:I had my carb done over the winter and have had a hard time getting the jetting to stay consistent. It seems that one day to the next needs playing with to get it to run good. I have checked for leaks and what not, the only leak I have is the air screw seems to get damp.
I have heard that the RB'D carb gets jetted "differently" than a stock carb. What is meant by that???
I keep checking the plug and it seems to stay dark even with leaner jetting?

Any thoughts?

After some screwing with it it rips, but I'm not looking forward to a test and tune with jetting before each ride.

You keep checking your plug and it stays dark.
Is this checking your doing on a plug chop or after
you have been riding ?

I spent the time and jetted my bike once and never
have to touch anything except the air screw unless
I go to WV and then lean out the main 1 size.

Posted: 11:56 pm Jun 18 2011
by Mr. Wibbens
My plug usually stays black, we ride so much singltrack and never get much of a chance to clean it out, even when my piston stuck the other day the plug was black

Posted: 08:16 pm Jun 19 2011
by rbates9
I ride mostly lower rpms and have been checking the plug after riding. I have done the plug chop at wot and it seems to be good there.

The air screw is about 1 turn out. 40 pilot.

Another thing that has happened to me the last few rides is I will get into a tight spot usually at the bottom of a hill and it seems to run right out of power, almost like I'm a gear too high. I tend to end up stalling it and when it starts back up (first kick) it seems to bog when I try to take off and then it will just clear right up and run fine.???

Posted: 09:12 pm Jun 19 2011
by TWMOODY
That sounds more like a float sticking or something along those lines.

You have a 40 pilot and a main of what ? 150/152 ?
What needle DEK/CEK and where is the clip ?
What altitude you riding at 600 or so ?

Posted: 09:15 pm Jun 19 2011
by Mr. Wibbens
Need to find the SSS

Won't have that problem

Last time I went riding we had snow on the ground. I went out today, it was in the high 80's, same jetting same air screw setting. Bike pulled forever on the bottom, no bog at all

Posted: 09:45 pm Jun 20 2011
by rbates9
I do need to look into that sss. Haven't had much time to play so the time I get I tend to just ride. I figure if I'm dark on the plug I'm safe but I would like to get the most out of it that I can. I ride with a few guys with the KTM 300's so they tend to think less of the KDX by nature but they don't get away in the woods!

Posted: 10:03 pm Jun 20 2011
by Mr. Wibbens
just go 2.5 turns out and see how you like it

From there it just takes very very tiny turns, like a 1/16" or less

You will know when you are there

2nd or 3rd gear with the motor under some pretty good stress, it will sound like it is going to bog, but it does not and it'll pull out of it

Posted: 10:08 pm Jun 20 2011
by rbates9
Good to know, Thanks. I have read about it but once the riding season started so did everything else.

Posted: 12:41 am Jun 23 2011
by Mr. Wibbens
I get into the SSS about :34

3rd gear

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Posted: 01:00 am Jun 23 2011
by Mr. Wibbens
Here's that rut I got hung up in :mrgreen:

[youtube][/youtube]

Posted: 01:00 pm Jun 23 2011
by Mr. Wibbens
I only had to touch my air screw once. Moved it out about 1/32"

Posted: 08:29 am Jul 13 2012
by Kaveman
Mr. Wibbens wrote:Need to find the SSS

Won't have that problem

Last time I went riding we had snow on the ground. I went out today, it was in the high 80's, same jetting same air screw setting. Bike pulled forever on the bottom, no bog at all

Alright, I am a noob. What is the "SSS"?

Jetting?

Posted: 08:53 am Jul 13 2012
by scheckaet
second sweet spot or super sweet spot