S&S GAL jetting help

S&S carburetor isues
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CasaPan
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S&S GAL jetting help

#1

Post by CasaPan » Wed Feb 11, 2015 11:29 am

Hello everyone,

At first , let me thank the Admins, Moderators, and everyone on this great forum...even I registered since a while, I never posted because I found every answer to my questions without asking, so....
Second, let me apologize in advance for my english, because it's not my native language (I'm French)...ok for reading, more difficult for writing :oops:
I own a Panhead since 2012 that I bought in New Mexico and then imported to France, then to Morroco where I live since 14 years...planning to move to Switzerland this year. She has been sold to me as a 48FL, but in facts, it is a 63' motor with external oilers, feeded by a 48' cam cover, Andrews mild cams, stock manual advance, suicide rocker clutch and stock hand shift, solid lifters, 1-1/2" , 132t primary belt 40/62t sprockets, OEM 4 speed tranny with 26t sprocket, stock rear & front wheel star hubs, with drum brakes, early 49' rigid frame (round, not flattened legs with square corners horn tabs), 48' offset springer frond end...The bike came with a 38 Mikuni carb; I ran the bike as it was during 2 years with no major problem except hard cold start due to ESOVL (Evil Shut Off Valve Leak) and not EML (Evil Manifold Leak) !! Beginning of last year, I imported the bike to Morroco, have put a S&S GAL Carb (bought on ebay from ABCGang)....wow...so nice look ! The carb came with a .070 main jet(.072 as spare), and .031 idle tube. Set it with 1-1/2 turns out, and made it my daily driver the whole 2014 year, almost 8.000 miles...she starts, runs very good...except a small cough at 55-60mph (only one cough, not more, everyday) that never disturbed me. I made a trip of 1600 miles/7 days in May in Morroco, with friends on old bikes as well, even on tracks, altitude, and some bad conditions sometimes...the old lady starts every morning and hits the road with no complain !!!
Last September, a changed a tappet (front Intake) as the roller needles broke...no damage at all, the needles remained in the roller...I pulled the cam cover out to check...everything is in order inside.
In November, I pulled the motor out of the frame, put a new sprocket shaft seal, pulled the heads out to check the pistons and cylinders... .010 over, nice shape...everything's ok. I payed attention when putting the heads back, and, of course, made a bubble test during and after installing the manifold..., and re-performed a leak test before putting the motor in the frame: no leak at all. I have put the Viton O-rings this time, as the previous ones, regular black, weren't in a good shape. So far...so good.
I have not run so much in December and January, due to lot of rain this year (not common in Morroco, but...global weather changing I presume :roll: ) and work.
Last week end, I took the bike for a run with friends...started good, ran good as usual, but during the run, after the a good 50 miles (motor at final heat), we went back home on a portion of highway, then running a bit faster than usual (65-70 mph)...the small "cough" that I know since I have the GAL went into several, successive cough, at a specific speed 60-65mph, but as soon as I give more gas, the cough disappear and the power is good (just before coughing, I feel a power loss)....
"EML !!!" :evil: ... I told myself !!! but once at home, I performed a vacuum leak test...but nothing...absolutely nothing, even a small tiny bubble :shock: the plugs were a bit white to me, not really white, rather creamy brown, but not as brown as I like them to be (poor gas quality :roll: )
Well, I've pull the carb out, cleaned the jets (main and idle tube), checked the float level and re-set it a very small bit, but nothing real convincing to me...ah...I have a moon filter, but the foam inside is in bad shape due to backfires (mostly at starting if the manual advance isn't set properly...that means it's rather an air horn than an air filter :lol: but it has been all the time like this, so nothing really new...
Yesterday, I took the bike to go to work...30 miles, and I went to the same Highway to test...same thing...cough at specific speed...nothing really disturbing actually, but...you know that guys, we always want our baby to run perfectly !!!
So I started to ask myself if I should be a bit more serious, and do a jetting work with this carb.... I really would appreciate any experience on jetting the GAL...
Of course, I've read and re-read the S&S GAL/GBL owner's manual, but still little confused on the role of the main jet and idle tube...they say main jet is only for final speed at final rpm....and idle jet is for idle rpm, even it has an influence on mid range rpm...
I am going to put my .072 main jet, as I found the plugs a bit white to me, as the run was at 65-70mph, which is a pretty high speed I guess...but as I gave more gas, and the bike pulled hard...I am not sure that the main jet is the culprit...what about the idle tube??? Any clue?
Help would be much appreciated...
Oliver



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Re: S&S GAL jetting help

#2

Post by 58flh » Wed Feb 11, 2015 2:19 pm

Oliver--Welcome abourd---Leave the main jet as is-(you said it pulled very nice with more throttle).---An ideal color PER/SAY is a tan or COCO-Brown on plug insulater.I keep mine slightly Rich so the color is Dark brown/Black!-More on the black side.I would find out what size is the intermiediate jet?-(As obviously the carb. has been played with because of X-tra jets in the package.BUT before you dig into it & risk getting a EML--just try opening the MIX a little at a time until you get a good COLOR on the plugs!--If you see white -then its NOT RIGHT!.Also The bike starts easy & runs good,So just try richening it for now.There is anotherway to determine if you need intermiediate jetting by shutting-off the Accel.-pump!-(To much to type here but S&S has a download on thir site how to do it!.I think we have a pdf on this site as well.Remember S&S carbs. are inherent with a sneeze/They all do it!-Until you FINE-TUNE THEM!/& there not hard to do.Make-sure all the easy stuff is right like points gap,& INDEX your plugs is a good thing so do that also.---The CV-Mikuni can be made to run REAL GOOD & no sneezes.-----Respectfully---RICHIE

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Re: S&S GAL jetting help

#3

Post by CasaPan » Wed Feb 11, 2015 4:01 pm

Thanks Richie,

concerning not changing the main jet, it makes sense because beyond the sneeze, she pulls pretty hard (so hard, that a friend with 103CI 09' Roadking with cams & injection map tuned shames each time I almost leave him at the green light :lol: ) !!! You tend to think in the same direction as my guesses...main jet is probably not the culprit...
The GAL hasn't an accel pump, it's a basic pipe with a bowl attached...the idle tube (or intermediate jet) is a 0.031
You're right, I didn't mention that the points are good & checked anyway, and the plugs Champion J12YC, in good shape (changed a month ago after a flooded situation that made them dying -poor plugs quality nowadays- :roll: ), set at proper gap (.028)
I totally agree about the right color of them, that's how I try to keep them as well...
I also tried to turn the richness screw a quarter out more (you know, the position where she almost dies at idle, on the rich side)...but got a lot of pain to cold start it...turned the screw back to its position since ever...and she fired up like hell !
S&S manual says: "larger tubes will richen the mixture in the intermediate range (...)"...which looks like my situation...probably I should order one .033

If someone has another experience, idea...you're welcome :wink:
Thanks again
Oliver

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Re: S&S GAL jetting help

#4

Post by VPH-D » Wed Feb 11, 2015 7:37 pm

I ran 031 idle tube and 72 main at sea level with good results on a stock sized motor back in the 70s.
VPH-D

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Re: S&S GAL jetting help

#5

Post by CasaPan » Thu Feb 12, 2015 12:47 pm

VPH-D wrote:I ran 031 idle tube and 72 main at sea level with good results on a stock sized motor back in the 70s.
VPH-D
Thanks for the info...I'm going to try with the .072, as I have it available right now...
I also found this, which helps: this is for the MGAL...but very similar to the GAL.
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Re: S&S GAL jetting help

#6

Post by 58bob » Fri Feb 13, 2015 12:32 am

CasaPan, not being an expert by any means, but your condition sounds a lot like the transition between pilot jet (0.031) and main jet (70). S&S went some way to rectify this by putting an adjustable intermediate jet in the later carbs for this reason. Mainly to help with larger capacity motors.....which I believe yours isnt.
Maybe others more wiser than I could help along this line, cheers.

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Re: S&S GAL jetting help

#7

Post by VPH-D » Fri Feb 13, 2015 7:41 pm

IIRC,the MGAL had an intermediate jet/tube. The GAL/GBL has only a main jet and an idle tube.
VPH-D

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Re: S&S GAL jetting help

#8

Post by CasaPan » Sun Mar 08, 2015 6:35 pm

Hi to all,

well, after getting a bigger idle tube (.033), I have put it in the carb, and everything's ok now ! No more sneeze at all ! The bike starts and runs like a charm 8)
I have put some Bosch +4 spark plugs as well, as recommended by Richie, and for sure they give a spark like lightning !!!
Thanks to all of you.

Cheers,
Oliver

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