pilot jet sizes

[george.361]

I am building a set of cards out of two different set from what I believe to be from a 750 and a 650 for a 1981 GS650L. I have all the parts to make them meet service manual specs except the pilot jet. OEM calls for 42.5, I have two 42.5 one 37.5 one 45 and one 32.5 Everything one the bike is stock, nothing fancy I just want to get it up and running good and smooth. It is possible to do this with odd sized pilot jets. I know the pilot jets and air screw settings control fuel from idle to about 1/4 throttle as well as play a role in continuing to deliver fuel else were throughout the throttle range. Do you think it will be possible to comp instate by adjusting the air screw. My guess is that more turns out the larger the number as in the 45 and less turns out for the 37.5 or 32.5. Is this right and will this work? If not any idea if you can just buy the pilot jet and were from. I also have larger needle jets(Y4) instead of (Y7) I could put in but I don't think this will help out any

[chuckycheese]

Can be done

Sure, you could do it and maybe make it run fairly well. Personally, I wouldn't do it. OEM (Mikuni) pilot jets aren't very expensive and they'll last as long as your bike does as long as you don't wreck them getting them in and out.

If you do it right, I think you'll be glad you did!:-D (Most especially since everything else on the bike is stock.)

[george.361]

yeah Im gona go ahead and buy new pilot jets. Do you think that upping the size from a 42.5 to a 44 would be a good idea, to help with the running lean characteristics of gs models or should I just account for this with the air screw

[chuckycheese]

Specs

I'd use the factory specified jets. Since you're running stock, you shouldn't have any trouble making it run great. Good luck!:-D