Pilot air jet - 650g

[JTsGS650]

I've been chasing a rich condition for awhile now which I seem to have made better by raising the floats by 1mm. See here:

http://www.thegsresources.com/_forum/showthread.php?t=123857

When I removed the carbs last weekend I checked over the jets and noticed that the pilot air jets were 150 instead of the 160 that the suzuki manual indicates. Since this jet meters air at low speed, I was wondering if it could be part of my problem? Thoughts?

Alternatively, I got the bike with < 6K miles on it and thought the carbs were completely stock. Could someone else with a 650 G confirm that they have 160 pilot air jets? As always, thanks in advance for your help guys.

 

[maro]

to be honest, I never measured. sorry. But I'd be curious to know. Okay, my post is useless. move along. :-k

 

[Steve]

Have you looked in the carb 'sticky' that is the first post of this forum? :-k

I did, and here is what I found in post #13:

Hello folks!

I took this from my SUZUKI GS 650 G SERVICE MANUAL
I hope this could help....


GS 650 GZ/GLZ (82)

idle r/min 1100-+/-100r/min
carb mik bs32ss (4 seprate carbs)
id no 34300
bore size 32 (1.26)
float height 22.4.+/-1.0 (0.88 +/-0.04)
fuel level 5.0+/-0.5 (0.20 +/-0.04)
main jet #110
main air jet 2.0
jet needle 5C45
needle jet Y-7
pilot jet #42.5
throttle valve #135
by pass 0.8, 0.7, 0.8
pilot outlet 0.7
valve seat 2.0
starter jet #45
pilot screw pre-set (1.5 turns back (mixture screw))
pilot air jet #160
throttle cable play 0.5-1.0 (0.02-0.04)
choke cable play 0.5-1.0 (0.02-0.04)

 

[GQROD]

I've been chasing a rich condition for awhile now which I seem to have made better by raising the floats by 1mm. See here:

http://www.thegsresources.com/_forum/showthread.php?t=123857

When I removed the carbs last weekend I checked over the jets and noticed that the pilot air jets were 150 instead of the 160 that the suzuki manual indicates. Since this jet meters air at low speed, I was wondering if it could be part of my problem? Thoughts?

Alternatively, I got the bike with < 6K miles on it and thought the carbs were completely stock. Could someone else with a 650 G confirm that they have 160 pilot air jets? As always, thanks in advance for your help guys.

I don't ahve a 650 but battled this on my 83GS550E, my pilot air jets were the wrong size, bike would not idle right. I replaced all jets including the air jets to stock with the help of MElodicMetalGod on this site since he has the same bike, and i got it to run less lean. However i had to go higher on my pilots to cure the lean problem.

1-So just use the jets you have in your bike to start before buying anything. Once you get it running then you can start changing air jets and other jets to get the mixture right. It will save you a lot of headaches to just clean the jets you have and test from there.

2-Going smaller or larger is weird on the air jets becasue i had #150's on mine originally ( not stock ), then i went to stock air jets but the rear diameter of the smaller jets is BIGGER than the higher number jets which show a smaller orifice. So don't go by just numbers, go by plug chops. Chances are if you go to stock pilot air jets all the jets will have to be stock numbers so it could run too lean.

Hope this helps.

 

[Steve]

I've been chasing a rich condition for awhile now which I seem to have made better by raising the floats by 1mm.

Just want to make sure we're talking about the same thing here. If you raise the floats, the carbs will tend to run richer.

Did you really raise the floats or did you add 1mm to your measurement? Since the floats are measured upside down, adding 1mm to the measurement will actually lower the floats when they are back in the normal, upright position. :-k

The best way to determine jetting is to do plug chops. You can find detail on how to do that on BassCliff's 'little' website.

.

 

[JTsGS650]

Just want to make sure we're talking about the same thing here. If you raise the floats, the carbs will tend to run richer.

Did you really raise the floats or did you add 1mm to your measurement? Since the floats are measured upside down, adding 1mm to the measurement will actually lower the floats when they are back in the normal, upright position. :-k

The best way to determine jetting is to do plug chops. You can find detail on how to do that on BassCliff's 'little' website.

.

Sorry Steve, I guess I meant to say that I lowered the float by adding 1mm to the measurement, which seems to have helped quite a bit.

Regarding the pilot air jet, my problem is that the Suzuki manual says that the stock jet should be a 160, however the ones in my carbs are 150. I wanted to know if this could be part of the cause my rich condition. Based on what GQROD said above I guess maybe not. I was also wondering what size pilot air jet others had in their 650 carbs.

 

[carey]

I just recently (couple of weeks ago) purchased an 82 650G to build a cafe bike and have taken apart the carbs to clean. The carbs on it (do not think that they are original to bike) had 150's in them, the bike also came with a spare set of carbs in really bad shape (someone had dipped them in something fairly caustic without taking them apart) I think that these were the ones from the bike. I am not sure what size is in them, but also the PO came me carb rebuild kits which also have 150's in the kit.

Carey

 

[GQROD]

I just recently (couple of weeks ago) purchased an 82 650G to build a cafe bike and have taken apart the carbs to clean. The carbs on it (do not think that they are original to bike) had 150's in them, the bike also came with a spare set of carbs in really bad shape (someone had dipped them in something fairly caustic without taking them apart) I think that these were the ones from the bike. I am not sure what size is in them, but also the PO came me carb rebuild kits which also have 150's in the kit.

Carey

1-Check your main and pilot jet sizes to see what they are.

2-Tune your mixture using plug chops after you clean the carbs and put them back in.

3-Then depending on which part of the circuit is rich either adjust the mix screws to correct the rich/lean condition or you may have to go to smaller jets.

4-You could go to 160 air jets but this may or may not make enough of a difference. By all means however only install the 160 air jets then do plug chops in order to see if it runs a little leaner, then you can take it from there.

5-Get a 1.5 amp trickle charger and a box fan this will take a while to get right.

6-I know that i'm not as experienced as other members on this site so i would definetly take everyone's advice and be methodical and see what works and what does not. That is what i did. Don't let me or anyone else stop you from trying something you feel may solve the problem, there is nothing like trial and error to teach you what will work best for YOUR bike. I know we all are here for the same reasons to get our bikes running right and help each other. I had a lot of advice that did not work for me but did indeed work for others, although time consuming and at times frustrating it taught me a lot to know what did not work on my bike and hopefully my bad experiences and my good ones can help others save a lot of money time and headaches and get back on there bikes. Check out my thread on "pilot jets to cure no idle " it might clear things up and show you how i got my bike running well with help from the knowledgable members on this site.

Hope this helps

 

[Steve]

Sorry Steve, I guess I meant to say that I lowered the float by adding 1mm to the measurement, which seems to have helped quite a bit.

Regarding the pilot air jet, my problem is that the Suzuki manual says that the stock jet should be a 160, however the ones in my carbs are 150. I wanted to know if this could be part of the cause my rich condition. Based on what GQROD said above I guess maybe not. I was also wondering what size pilot air jet others had in their 650 carbs.

OK that clears that up.

If you have 150 air jets, they will admit less air than 160s, so yes, they will richen the mixture. Can't say what is in the carbs on my son's 650, but it might not matter anyway ... the bike has pods and a pipe, and I presume it's jetted to match, as it runs quite well.

.