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TOPIC: Re:37.5 or 40 Pilot Jet Forum Tools Post New Topic Show latest posts Rules

#873749 MJScore (User) Platinum Boarder Posts: 1128 37.5 or 40 Pilot Jet 2 Years, 10 Months ago   What are the benefits of going to a 40 pilot from a 37.5 pilot? I right now running a K&N RC1980 filter, Freedom 4" True duals, 172.5 main, 37.5 pilot, Baron's needle 3rd clip w/spacer & 2 washers and PMS 2 1/4 turns out. I've also changed the float needle to a Grizzly for going pumpless. What would this change going to a 40 pilot? How would it effect performance or gas mileage? Right now it's running good but I've seen some people here going with the 40.   Logged     20171228_185653 by Michael Score, on Flickr   The administrator has disabled public write access. #873750 texasscott1 (User) Two of a kind Platinum Boarder Posts: 4486 Re:37.5 or 40 Pilot Jet 2 Years, 10 Months ago   I can't see the reason for changing from the 35 much less all the way to a 40. Only so much gas can be squeezed through the small pilot ports anyway. Partially blocking the air jet at the mouth of the carburetor makes for a richer idle even with a 35.   Logged     My 99 Standard Test Mule Scott B.   The administrator has disabled public write access. #873752 davej (User) Platinum Boarder Posts: 18167 Re:37.5 or 40 Pilot Jet 2 Years, 10 Months ago   Going to a 40 with your setup on a 1700 will get you closer to a proper AFR. It will give you a little quicker warm ups and take care of any low speed hesitations if you have any. It will also give a little better throttle response on the low and mid ranges. Everyone ask about MPG. All I can say is that you will get better MPG if you run lean rather than rich or in a area of AFR that is correct. Our bikes from the factory are rated to get around 36mpg and with a few mods and keeping within and around an "average" AFR of 14-14.5 on a hiway cruise you will get in the low to mid 40's at best. Anyone getting better than that is running on the lean side of the AFR, likely closer to an AFR of 15 and above. Then again if you are happy with the way yours runs leave it alone.   Logged     dave   The administrator has disabled public write access. #873759 MJScore (User) Platinum Boarder Posts: 1128 Re:37.5 or 40 Pilot Jet 2 Years, 10 Months ago   davej wrote: Going to a 40 with your setup on a 1700 will get you closer to a proper AFR. It will give you a little quicker warm ups and take care of any low speed hesitations if you have any. It will also give a little better throttle response on the low and mid ranges. Everyone ask about MPG. All I can say is that you will get better MPG if you run lean rather than rich or in a area of AFR that is correct. Our bikes from the factory are rated to get around 36mpg and with a few mods and keeping within and around an "average" AFR of 14-14.5 on a hiway cruise you will get in the low to mid 40's at best. Anyone getting better than that is running on the lean side of the AFR, likely closer to an AFR of 15 and above. Then again if you are happy with the way yours runs leave it alone. Getting a proper AFR is what it should be. I do notice a little hesitation when I get on it sometimes. Also a Harley shop should have the jet, right?   Logged     20171228_185653 by Michael Score, on Flickr   The administrator has disabled public write access. #873784 davej (User) Platinum Boarder Posts: 18167 Re:37.5 or 40 Pilot Jet 2 Years, 10 Months ago   MJScore wrote: davej wrote: Going to a 40 with your setup on a 1700 will get you closer to a proper AFR. It will give you a little quicker warm ups and take care of any low speed hesitations if you have any. It will also give a little better throttle response on the low and mid ranges. Everyone ask about MPG. All I can say is that you will get better MPG if you run lean rather than rich or in a area of AFR that is correct. Our bikes from the factory are rated to get around 36mpg and with a few mods and keeping within and around an "average" AFR of 14-14.5 on a hiway cruise you will get in the low to mid 40's at best. Anyone getting better than that is running on the lean side of the AFR, likely closer to an AFR of 15 and above. Then again if you are happy with the way yours runs leave it alone. Getting a proper AFR is what it should be. I do notice a little hesitation when I get on it sometimes. Also a Harley shop should have the jet, right? Yep a HD shop will have it. Ask for a pilot for an HSR42 carb and it will work. If you tell them it is for a Yamaha you will confuse them and they will tell you they can't help you.   Logged     dave   The administrator has disabled public write access. #873802 brianmac (User) Platinum Boarder Posts: 2180 Re:37.5 or 40 Pilot Jet 2 Years, 10 Months ago   yeah, and i wanna know how much they charge you for a 3$ jet at a harley dealer, post it!   Logged     [img size=150][/img]   The administrator has disabled public write access. #873813 davej (User) Platinum Boarder Posts: 18167 Re:37.5 or 40 Pilot Jet 2 Years, 10 Months ago   brianmac wrote: yeah, and i wanna know how much they charge you for a 3$ jet at a harley dealer, post it! I think they are about 7fiddy at a HD shop.   Logged     dave   The administrator has disabled public write access. #873829 Blackroadie (Moderator) Sometimes I wish you were a pinata ! Moderator Posts: 9480 Re:37.5 or 40 Pilot Jet 2 Years, 10 Months ago   I had to get an 'emergency' jet at a HD shop about 10 years ago.. it was 7 bucks.   Logged     Last Edit: 2015/04/05 17:45 By Blackroadie.     The administrator has disabled public write access. #873868 pangea33 (User) Gold Boarder Posts: 671 Re:37.5 or 40 Pilot Jet 2 Years, 10 Months ago   Blackroadie wrote: I had to get an 'emergency' jet at a HD shop about 10 years ago.. it was 7 bucks.   Logged     Last Edit: 2015/04/05 20:03 By pangea33.   Ben C - Cary, NC 2001 R* 1600   The administrator has disabled public write access. #873927 Blackroadie (Moderator) Sometimes I wish you were a pinata ! Moderator Posts: 9480 Re:37.5 or 40 Pilot Jet 2 Years, 10 Months ago   I switched from a 37.5 to a 40 last year. You will notice quicker warming up from a cold start, and it tends to run a little bit better all the way through the ranges. As far as gas mileage, I averaged 42 before, and I may have lost one mile a gallon now. nothing I even notice. It is less hesitant and snappier on the low end.   Logged     Last Edit: 2015/04/06 08:14 By Blackroadie.     The administrator has disabled public write access.

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