help with jetting, please

[bildough]

I have a six day which runs a main jet of 130. I live at 4000 feet elevation. Last weekend i went down to 1000 feet elevation and my bike that always starts first kick wouldnt start unless it was pushed. when I got home boom first kick. what jet do you think i should change to at that elevation change.

Bill Cappel
74 six day
77 berkie
73 jackpiner
74 mettco replica

[hrbay]

Bill, you may just need to raise the needle one clik, to compensate for heavier air. Less air ( home ) less gas, more air( -3000 ft ) more gas. Try to keep your air mix the same, but I would carry a 5# richer pilot jet just in case.

GC

[firstturn]

Bill,
  How did the bike perform after you got it started?

Ron Carbaugh

[bildough]

actually once the bike was running it ran tather well after it cleared. but it was impossible to get started. If it died during the moto I would have been through and I cant always rely on a BIG push from people on the line. It took a hell of a push to clear .

[bildough]

i was hoping going to a 125 main jet would be the correct course of action. The plug looks fine also. What is the prognosis?

[firstturn]

Bill,
  This is just a shot in the dark,it is difficult not looking at the bike in person, but if the bike is  hard to start I would be looking at the quality of fire.  I would check all the plugs to the coil and be sure that you have no problems there.  Also you can just do a OHM check to be sure you have good ground from the ignition to the coil.  What type of ignition do you have?  If we need to talk I will be at home after 3PM Central........830.895.958.

Ron Carbaugh

[bildough]

ron the coil connection is fine and spark is great. its just the elevation change from 4k to 1k. starts fine now back at 4k feet but wont start at 1k. i was also thinking that the pilot jet is 45 and i could go down to a 40 or 35 if you think that would help. once it runs it cleansd out and runs fine

[hrbay]

Bill, you may just need to raise the needle one clik, to compensate for heavier air. Less air ( home ) less gas, more air( -3000 ft ) more gas. Try to keep your air mix the same, but I would carry a 5# richer pilot jet just in case.

GC

[firstturn]

Bill,
  How did the bike perform after you got it started?

Ron Carbaugh

[bildough]

actually once the bike was running it ran tather well after it cleared. but it was impossible to get started. If it died during the moto I would have been through and I cant always rely on a BIG push from people on the line. It took a hell of a push to clear .

[bildough]

i was hoping going to a 125 main jet would be the correct course of action. The plug looks fine also. What is the prognosis?

[firstturn]

Bill,
  This is just a shot in the dark,it is difficult not looking at the bike in person, but if the bike is  hard to start I would be looking at the quality of fire.  I would check all the plugs to the coil and be sure that you have no problems there.  Also you can just do a OHM check to be sure you have good ground from the ignition to the coil.  What type of ignition do you have?  If we need to talk I will be at home after 3PM Central........830.895.958.

Ron Carbaugh

[bildough]

ron the coil connection is fine and spark is great. its just the elevation change from 4k to 1k. starts fine now back at 4k feet but wont start at 1k. i was also thinking that the pilot jet is 45 and i could go down to a 40 or 35 if you think that would help. once it runs it cleansd out and runs fine

[Larry Perkins]

My guess is that it will start well at that elevation with a 35 pilot jet and a 270 or 273 needlejet.  The main sounds lean for there but a plug check will tell.  Be sure the slide is not worn also.  

Larry

[firstturn]

Bill,
  My problem with this entire situation is that it won't start and the plug looks fine.  I raced at sea level and moved around the state to venues that were as high as 3000 ft.(same difference as your=3000ft) and never had to do anything other than possibly change the needle setting.  I was probably always running larger bore than yours, but not encountered the same problem with good plug readings.
  I was fishing for a ignition related problem(won't be the first time I am wrong via long distance problem solving).  If you have a MotoPlat the RPM that the engine has to turn over to start is much greater than that of a PLV by as much as 300 to 400 RPMs(this is Danes area sooo I could be off on RPM).  You can try what you suggested on the jets, but I am just not convinced.  I hope I am wrong[8D].

Ron Carbaugh