Pilot jet rules and regulations

bulitnv · Post by **bulitnv** » February 23rd, 2009, 2:49 pm

Any situation where a 58 pilot jet might be a good idea?

Can't seem to get my AF running quite right.

Tried every combo with 170/175, 48-55, needle 2nd to 4th clip.

(PJ) by the way. On a 2001 motor built new 1 month ago by SH.

Don't want to dwell to much on idle, but it needs to be better.

Idle adj knob tries to get the bike to idle at at "all the way open", but then the bike surges at chop of throttle (lean?)

Same results pilot 48-55. Could a 58 fix this?

Doesn't seam to have an air leak.

Carb is clean, nothing plugged.

I am almost at the "throw money at it fix" (buying a new carb) thinking my carb parts (slide etc) might just be warn out.

Thanks for any insight. This is the first CR500 I have had(3rd overall) that has given me fits tuning.

Chris

Post by **AlisoBob** » February 23rd, 2009, 2:52 pm

If its still pretty cold out, and your at low elevations... you very well may need a bigger pilot.

bulitnv · Post by **bulitnv** » February 23rd, 2009, 2:59 pm

Thanks Bob, I am at sea level here in good ole Whittier CA. Not too cold, but I will give it a run.

bulitnv · Post by **bulitnv** » February 23rd, 2009, 3:18 pm

...not sure what a pilto jet is, can someone transform that to pilot?

bulitnv · Post by **bulitnv** » February 23rd, 2009, 3:22 pm

........I have my throttle cable adjusted so that there is 1/8" or so free play and the slide is bottomed out. Is it still possible to get the bike to idle with such a configuration..............?

iggys-amsoil · Post by **iggys-amsoil** » February 23rd, 2009, 5:58 pm

Yep go 58. I had mine ported/with the PJ and at sea level a 62 at a 1/4 turn out and its still not big enough until I get to 3000'.

bulitnv · Post by **bulitnv** » February 23rd, 2009, 7:29 pm

Much thanks! I am heading towards Lucerne or Stoddard Wells this weekend, I will try it out.

dannygraves · Post by **dannygraves** » February 24th, 2009, 9:37 am

first off, you say its a PJ, well, the PJs like a fatter pilot. the '80s motors came with a 60 pilot stock.
where is your air screw? the air screw and pilot jet directly relate to each other. if it runs better when you turn the air screw in, then you need a richer pilot jet. you should try to target a pilot that keeps it running good at around 1 1/2 turns out.
that low elevation you are at combined with some delatively low temps will probably require more fuel anyway.

mega491 · Post by **mega491** » February 24th, 2009, 11:53 am

Surging? The first thing I would do is a leakdown test.

dannygraves · Post by **dannygraves** » February 24th, 2009, 11:56 am

I'm gonna agree with mega here, unless your air screw is out too far, I'd be looking for vacuum leaks. check the trans oil level, look for smoke while running and check the bottom of the cases where there could be some cracks. also the stator side seal.
the most common though is a slipped out base gasket. the paper ones get pushed out, the cometic base gaskets are the only ones I'll run because they are a metal shim design.

dannygraves · Post by **dannygraves** » February 24th, 2009, 11:57 am

oh, and cracks in a pipe, or leaky header seal will also cause a lean condition.

Ported&Polished · February 24th, 2009, 12:04 pm

Raise the needle and turn the screw so it's at 1 turn out. Now if it still surges, it's a leak somewhere.

Post by **AlisoBob** » February 24th, 2009, 12:17 pm

dannygraves wrote:oh, and cracks in a pipe, or leaky header seal will also cause a lean condition.

mega491 · Post by **mega491** » February 24th, 2009, 1:05 pm

Overtightened base bolts will pull those "ears" down in the area at the respective corners and let air in inbetween the base bolts in the area of the transfers. Seen that many times. Reed cage does the same thing if overtorqued. Snug is better than tight. Factory torque recommendation in all cases for me.

ISBB · Post by **ISBB** » February 24th, 2009, 2:24 pm

41mm PWK owner here and lovin life..

MUCH MUCH MUCH better of my PJ that i fought with all the time.. It was never just right.. Right now my PWK is a little fat can i can tell ( tiny bit of spooogage )

even being a tiny bit on the fat side it runs like a raped ape and pulls hard all the way till BOOM!!!

mega491 · Post by **mega491** » February 24th, 2009, 3:10 pm

Have a PWK Airsrtryker on mine. INSTANT throttle response off idle (250 ignition also). Can only imagine the over-rev that 41 delivers. Since I only MX will stay with the 38 though.

Mega491

GenIII CR5
84 CR5
Yamaha
Maicos
Triumphs
Harley
69 El Camino

bulitnv · Post by **bulitnv** » February 24th, 2009, 3:24 pm

My air screw is at 1.5, seems to run best there. The surging only happens when the idle adj knob (choke) is opened way up(about 75% or more). As long as that idle adj knob is opened way up it surges with every jetting config I have tried (only surges when throttle is cut) otherwise, with the idle adj knob turned in a little it runs pretty good. Just won't idle.

Been checking for leaks, nothing on the outside, sprayed the thing down with wd40 and carb cleaner. Engine is basically brand new, just had the cases split and replaced by SH. Unless I have a main seal between the tranny and the crank unseat itself(since all seals were new), It should be fine on the inside. No moisture inside the stator area.

Pipe is new, no leaks. RTV around the head gasket so don't really have much blow by as typical by these bikes.

The first time I drained the tranny oil I only drained .450l, down about .150l from full. But I can't say for certain it was full when I started. Every other time it has had about .650l or so put in, about the same amount drained. I will check again this weekend as I pretty much change my tranny fluid after every day of riding.

Gonna try the 58 pilot this weekend, if I still can't get it to idle right I will do a leak down test.

Thanks for all your help fellas!

Chris

hagendog · Post by **hagendog** » February 24th, 2009, 4:09 pm

Have you taken the choke out and inspected it. I've seen more than one of them fail, sometimes they spin and actually don't do anything.

bulitnv · Post by **bulitnv** » February 24th, 2009, 7:41 pm

Yes, the choke is in great shape. It works perfectly.

Thanks though!

Chris

BannedCR500Riders.com

Pilot jet rules and regulations

Pilot jet rules and regulations