Another jetting thread

[wastedyouth02]

So i bought my 500 back from my friend for $200 after he tore the bike down and got it all powder coated . He said he couldn't get it to start, the ground wire on the coil was disconnected. So now it starts but does not idle, holding the throttle just slightly open it stays running, then pulls alrite through mid range but just as its about hit the power band it falls on its face and makes almost a rev limiter sound. Cleaned the carb thoroughly found that the air screw's o-ring had disintegrated so i replaced with one that was almost the same size (same I.D. slightly larger O.D.) I will be ordering a OEM one but funds are tight and they want you to order the screw also. How critical is that o-ring? Adjustments on the screw do nothing but could be an effect of the o-ring? Im running 32:1 castor, good compression, haven't done a leak down test, reeds are about one ride old and look perfect. The choke also seems to make no difference. Im not real good with this jetting nonsense so any ideas are appreciated.

[maddog1927]

try cleaning the carb again. With the little red straw on a can of carb cleaner spray it through all jets, passage ways etc. Make sure nothing is blocked.

[wastedyouth02]

I cleaned it once and put it back, and it acted the same. So i pulled it again cleaned it normally with the can and straw then took air to it then carb dip then air again, im 99% sure its completely clean.

[qkenuf4u]

are you running the stock carb ? what jets are in it now (pilot, needle, main)

you def. need the correct o-ring on the pilot screw or youll have an AIR LEAK which is a bad thing. get the correct o-ring and jet accordingly..

sounds like its RICH on top.. (main to big) as long as i understand what youre saying about how its acting.. cutting out/blubbering = RICH ,, lays over and wont rev = LEAN (careful ya dont burn it up-its really cool up there right now) start bringing your main size down a little at a time..
there are more than enough threads about jetting on here that you should be able to get it close.... i had to upgrade to a PWK to get mine to idle correctly. sorting the other jetting now..

[plynn41]

Check out the sticky threads on jetting in this forum. You'll be far less mystified by the jetting process.

[wastedyouth02]

Ok so:

Started with god knows what i couldnt read the jets, no idle top end falls on its face

Picked up a 58 slow 170 main, was told this was stock as i didnt have a manual at the time. Same results as before no idle top end falls on face choke has no change air screw gives no change

Got a manual and says stock is a 55 slow so i went to that and a very slight change still no idle still no top end still no choke change but the airscrew seems to make a slight difference in the bottom. To me the top end sounds starved of fuel or something so i moved the needle to the most rich setting clip on bottom groove. Air screw 3 turns out still gave no idle.

Got a 50 slow (the next size down they had in stock) and a 175 main (next size up in stock) still no idle BUT will start without giving it some throttle eg. I kick it it goes ding ding ding and dies, choke still seems to make no difference air screw seems to make no difference now and the top end is still fubar. And thats where Im at today im starting to believe i have an issue somewhere else.

This video is of the latest changes when i get on the back straight its full throttle non stop thru 3rd gear. And sorry for the wind interference but it comes with living in northern AZ


Reeds are clean and seal good, FMF gnarly pipe FMF muffler, other then that i believe its stock. It has a boyseen stator cover with a yellow wire coming out of it. Im assuming this is a lighting coil and is now giving me suspicion to believe something is fubar ignition wise. Any ideas guys?

[kdizzle]

your close enough on the jetting that it should rap out better than that. You are way rich for some reason. Check the float valve and level, then try the needle clip all the way to the top.

If you got a couple bucks maybe spring for a complete carb rebuild kit or possibly even a PWK if you got the loot.

For what its worth, my bike ran very similar to that when the main jet fell out and was laying in the bottom of the float bowl.

Rule of thumb on the 500 is that if it blubbers like that its rich (as stated above)

[wastedyouth02]

So i went the wrong way with the main, i believed it was lean. I see the spec for the float level but whats that measurement to.

[scooter5002]

I will risk sounding like a dumbass here, but did you check to see where the idle setting is? I assume you know it is in the choke knob and if you didn't well..... turn it to see if it makes a difference. As well, yes that o-ring is very important, as mentioned previously. Since I don't know I will ask. What's the elevation where you live? Is that compounding your problems with jetting to rich for higher altitudes?

[wastedyouth02]

yea the idle adjustment nor choke setting effects its idle, is that a good indication that my pilot is still too rich? And yes im at 5000ft.

[scooter5002]

Ouchie! That makes a difference. When I lived in Calgary at 3500ft the rule of thumb was down 10% on jetting, I would think probably 15% for your elevation. If the stock main is 170 then try a 150 or whatever is closest and you can adjust from there. Same thing on the pilot. Probably set your clip back to stock setting for baseline testing and try it. Its been 10 years but I think I ran a 155 and a 45 pilot and I'm gettin' old. Memory ain't what it used to be. So you should be down a little bit from those jets.

[scooter5002]

Oopsy, I forgot. Throw in a new plug and make sure the gap is right as well. Eliminate that part of the equation for potential trouble and you will be able to get a good read on your jetting.

[100hp honda]

im similar elevation with 50/170 if i recall. if that video is recent then your temps are still fairly hot. might have to drop into the 160ish range. not idling is the first indicator pilot is too big. drop a step at a time until you get desired results. if you been riding for a while with it super rich then you may have it really loaded up. might have the correct main in there but it will give you a false reading because you have buildup of fuel. make 3 or 4 blasts through the gears to get any excess fuel out, if it still wont clean out then drop main. if float is wrong either of 2 things will happen
1- shit will be pouring out the overflow
2- it will close the needle before bowl is full. youll never know this condition unless you ride long wfo runs and bowl will go dry.

do not put a 150 in there anybody that knows anything about a 2stroke never drops 20 sizes in a single leap then works their way up. get handful of jets and work down.

[wastedyouth02]

Yea that video was today and were still in the mid 70s high, and i havent riden it due to the lack of it runing. Tomorrow ill go get a 165 and down another pilot and see what happens

[qkenuf4u]

im just gonna say that if youre running the stock PJ carb youre gonna chase your tail trying to get an idle... did all the stuff youre doing and got a 10second idle on my PJ.. got the PWK and within 10seconds had a nice clean idle... just need to get the right needle now (dgn,dgj,dgl) and im thinking that will clean up my mid-throttle/cruise..

as stated, put your needle back on #3 and change one thing at a time... youll know real quick when you go lean on the pilot.... i need to bump mine back up to a 48-52 to get rid of the lean BINGS at cruise....
good luck

[scooter5002]

I've owned a CR500 and never had any trouble getting a decent idle or overall jetting problems. Whether I was at high altitude or where I'm at now which is about 550 ft above sea level. Everyone else modded the shit out of their motors that switches over to a PWK? Sorry for the hijack but this is rather interesting

[qkenuf4u]

I've owned a CR500 and never had any trouble getting a decent idle or overall jetting problems. Whether I was at high altitude or where I'm at now which is about 550 ft above sea level. Everyone else modded the shit out of their motors that switches over to a PWK? Sorry for the hijack but this is rather interesting

the cr is the ONLY bike ive EVER not been able to get to idle all day long on the stock carb.... some others have had the same experience as you scooter...lots have not..

[scooter5002]

Wow Thats pretty friggin amazing cuz I've owned 2 Honda big-bores and they both ran like a charm ( and 1 piece of shit KX500 but we ain't goin there) and if you knew MY history thats AMAZING to have that kind of luck. And no doubt I'll start havin troubles now that I've talked about it. Lol

[wastedyouth02]

Thanks to all for the feed back. I stepped down to a 48 and a 165 and it got ALOT better stepped down to a 45 and 160 and now the thing frekkin flys. Gonna wait for my new airscrew assembly to show up and ill start fine tuning some more so itll hopefully idle