Jetting!!! Again and again and again!

[Hillclimb#42]

Sounds like a good find. I think 172 is a little fatter than my 500. 170 is what I usually run. There is a jetting chart that is found on a sub-menu on the main page that is very accurate. Also FMF has their own recommendations. If they both are the same, you really will know the answer. I think the FMF just adds a step fatter on the needle adjustment from stock and the Pro Circuit goes leaner a step. Of course, if its aint stock, it's only going to give you a starting point. It will probably sound fat in the garage idling before it gets warmed up and cleaned out. Jetting for the main is changed when its running fat Wide open. You are thinking the idle jet is fat, but I would wait to see how it acts after riding til cleaned out good.

[98kaw500rider]

OK , Thanks for your help. I paid 500.00 for it with a title , brother in law just lost intrest in it and wanted it out of his garage. I got it started after about 5 kicks  after i cleaned her up. One issue that i am having is the kick starter , seems like about 2 kicks out of 5 it goes slack. I ordered a new ratchet gear and spring for it so i hope that fixes the issue , is that hard to change out ? This might not be the right thread for this question so sorry.
Thanks

[Danger4u2]

kick starter.
http://www.kxriders.com/forums/index.php/topic,2318.0.html

[Purpletj]

I contacted Sudco to try and purchase some jets. Found out they only sell  them in a four pack. Im curious how your buying the singles?

[Friar-Tuck]

P.J.
 If there is not a bike shop in the area ( Like Myself) there are severl other options.
   Most other motosport,  Service Honda etc will sell individual jets.
  I would recommend making sure the jets are actually Keihin. (drunken star stamp)
I have had several bikes over and although the jets were the correct dimensions externally, the flow rates were questionable.   I had a crf80 one of the kids friends re-jetted and appeared to have done everything to get his kids bike to run properly.  It would start and idle great but at half throttle it wouls stumble, and die if you tried to open it up.  The culprit was an off brand main. I had a keihin, put it in and we got it to scream.
  This may have been an isolated incident, but someone else may be able to verify the same type story...
Tuck\o/
   
http://www.carbparts.com/

http://www.jetsrus.com/

http://www.motorcyclecarbs.com/index.cfm

http://www.factorypro.com/products/Jets,%20Keihin,%20buy.htm

[Purpletj]

P.J.
 If there is not a bike shop in the area ( Like Myself) there are severl other options.
   Most other motosport,  Service Honda etc will sell individual jets.
  I would recommend making sure the jets are actually Keihin. (drunken star stamp)
I have had several bikes over and although the jets were the correct dimensions externally, the flow rates were questionable.   I had a crf80 one of the kids friends re-jetted and appeared to have done everything to get his kids bike to run properly.  It would start and idle great but at half throttle it wouls stumble, and die if you tried to open it up.  The culprit was an off brand main. I had a keihin, put it in and we got it to scream.
  This may have been an isolated incident, but someone else may be able to verify the same type story...
Tuck\o/
   
http://www.carbparts.com/

http://www.jetsrus.com/

http://www.motorcyclecarbs.com/index.cfm

http://www.factorypro.com/products/Jets,%20Keihin,%20buy.htm

I understand I can buy the kleihin at any local shop. I was just trying to avoid the higher cost. Sudco has some really good pricing. If you know what i mean.,

[Purpletj]

The cheapest I have found at my local place is around $6.50 BTW.

[HammeredFlat4]

I just checked my jetting while going through my bike, I have a 172 main and a 50 pilot.    I am going to order some more jets tomorrow, I think I will start with 168/55.  99 K5, engine is stock as far as I know besides the crank being balanced, FMF Gnarly with FMF Turbine Core, 40:1 castor 927 and 91 octane.

[fatboy2k500]

Just pulled my carb apart on the 500 for the first time to do a little cleaning before heading to Oceano dunes (pacific coast in CA) tomorrow morning.  It did have a 168 Main in it, but had swapped to a 172 to try to get it to stop pinging in mid-range on 91 octane (now running 110 leaded and problem is gone).  Pulled the 172 out and exchanged for a 165 and yanked the pilot (which as 58) and replaced with a 55.  Trying to get some of the blubber out of this thing by leaning a bit (until I get some surging then coming back).  It's got a Zip Ty pipe and silencer on it, RAD valve (which I'm seriously thinking aout replacing).  Runs okay but doesn't feel like a 500.

I was thinking of getting a couple steps in either direction (from stock) to play with but don't want to spend all weekend long jacking with jets in the sand if I don't have to.  What do you think of 165/55 on 110L fuel with current mods?

[Jopiz]

My bike is not a 500, but didnt bother making a new topic to the 125/250 side. So i borrow this one.

My bike runs nice at 3/4 throttle. I did a plug test and it was perfectly tan (@ 3/4) . When i open my throttle to max, it feels like the bike stalls. Aren't main jet and needle taper only responsible for 3/4-1 throttle openings? This claims ( http://www.nsr-world.com/tuning/250-tuning/carburation%20index/jetting/images/jet-chart.gif ) that needle position makes no difference at 3/4-1 position.

Main jet is stock, Pro circuit and Boyesen recommends the stock main jet.

 Im too afraid to do a wot run and then do a plug test.

Am i too lean or what?

[Hillclimb#42]

I have seen bad spark plug caps do that. Partially clogged main. Powervalve gummed up. And of course the almighy answer of "crank seals." Reed corners gone. Contaminates like water in the gas, but then you would also have popping and probably stalling.

[sandman540]

Hey all. I got my cherry 95 K5 out after a long recovery of a broken right leg. I did a hotlap around my 15 acre woods and found that at 3/4 to wot it was flat and falling on its face. Upon removing the carb i found a tiny and i mean tiny piece of varnish on the needle jet and in main jet. A can of carb cleaner and a bit of elbow grease removed the offending goo. Reassembled,reinstalled the carb after inspecting everything, Holy Cow she is a missile now!. Back to 100% I just would like to give everyone a big thank you for having this site and all of the awesome technical info and advice. When the K5 is running great its a blast there is no comparison!!   Sandman

[Rude Riders]

Anyone here know about a DGH needle? Thats what i have in my 92 k5. I went ahead and ordered a N82M cause it seems thats what everyone is running with good results. Just didnt know about the DGH.
Thanks,
Ryan

[livenlife699]

I Have a problem getting my bike to run properly in the top end, its almost bogging out..I have a FMF exhaust,vforce3,ported n polished cylinder with a wiseco piston jetted now with a 175main 58 pilot and needle on the 2nd clip from the top. It runs much better than before with the 168main at 3clip on needle but it will not got past 3/4 throttle so im a little confused at the moment as ive been playing with it for a few days. Should I go more gas since its +1 piston or...? Any suggestions would be appreciated for sure

[jonny500]

i have no idea what jets you need to run but i can offer some carburation theory. you say the you are on a +1 piston. if the cc of an engine is increased then the volume of fuel/air pulled throught the carb is increased and as it is being drawn through the same size venturi (the carb is standard) the velocity of the fuel/air has to increase. if velocity is increased then pressure in the venturi is lower. so in theory the jets would need to be reduced in size if running a larger piston. however 1mm on and 86mm bore would not make much difference