Advice on jetting please: Change needle height or mains?

[ironsheik]

Hello y'all,
I've got an 83 gs1100ed with a Yosh race pipe and K&N filter in the stock air box with lid on. I just got the bike running ok but it is still lean from 1/8 throttle to wide open. I still need to do a half throttle plug chop. I started with a 117.5 main and the needles at 4th clip from the top and was popping all over the place on decel. I then moved the needles to the 5th notch and opened the mixture screws a 1/4 turn to about 3 turns out.

It's much better but probably slightly lean on all circuits still. It pops slightly on decel from high rpm and the plugs could definitely be darker at WOT. Should I go to 120s and leave the clips for now or should I move the needles one more space? The plugs looks the same at 1/8-1/4 throttle and wide open. I get a tiny bit of pinging when opening the throttle wide in high gear from 2k rpm. Thanks for any advice!

Josh

[7981GS]

I answered this question in your other thread. Try it.

Daniel

[ironsheik]

Thanks! Really though, jump from 117s to 125s? It's just a bit lean. But I guess you're assuming I'm making up for too small mains by moving my needle so far up? I guess I'll get them on order. Sheesh. This stuff can take forever the first time you do it! So many GD variables!

[7981GS]

Thanks! Really though, jump from 117s to 125s? It's just a bit lean. But I guess you're assuming I'm making up for too small mains by moving my needle so far up? I guess I'll get them on order. Sheesh. This stuff can take forever the first time you do it! So many GD variables!

You are trying to make up for the smaller pilot jet (40) and mains.
A friend with the same bike and the same mods, is running 130 mains and the other recommendations on his. Start there (125's) and check your results.

Daniel

[ironsheik]

Except I'm pretty sure I've got stock 45 pilot jets. Did you mean the pilot AIR jet? I've got DJ 132s so maybe I'll try them before I order the 125s. They're pretty close.

[7981GS]

You are correct on the 45 pilot jet, my bad.
I believe that we went TO a 47.5. <Checked with him yesterday. (Edit)
Try the jets that you have as they come close to a Mikunl 123/124 size.

Daniel

[ironsheik]

So I put in the DJ 132s and with the needles clipped on the 3rd position it was lean at 1/8, 1/2 and full throttle and hesitating from 2-4k or so and popping a lot. I raised the needles one position to the 4th clip from the top. It's better but still lean on the pilot and surging a bit at 1/8 throttle. At 1/2 throttle the plugs look perfect so I'm going to keep the needles at 4 for now. At WOT it doesn't pull as smoothly as it did with the 117.5 mains and the needles at the 5th position and it's showing just a hair lean even! I think the air screws are at about 3 turns out for highest idle.

I hope I'm doing the chops right. I've been doing WOT from 2k up in 4th gear for about 6 seconds. New York city is a hard place to do these things!

So it seems like I might need 47.5 pilots regardless? Or should I wait to get the mains/needles right? I don't get why I would be just as lean at WOT with the DJ 132s (needles at 4) as with the Mikuni 117s (needles at 5). I'm getting there. It's time consuming but kind of interesting at least.

Thanks for any help.

Josh

[Tom R]

47.5 pilot jets are standard fare for a stage 3.
Not sure what brand of needles you have, but with factory pro needles 4 clips from the top I ended up at 47.5 pilots, 142.5 mains, and fuel screws 3 turns out.
It's pretty close.

[ironsheik]

Well I shouldn't be up at stage 3 with the stock airbox and a K&N drop in filter. I think I'll go back down to 120s and see where I'm at. I took it out last night and tried to look at the plugs but it was dark. WOT to redline in 1st or 2nd is great in the midrange and then stumbles/surges at 7k and 8k and does not pull as strong as with the 117s.

I'm at a bit of a loss. Maybe my floats are causing some of this? If I could hardly get the bike to rev with 117.5s and the needles at the 3rd position and then moved to them to the 5th position and got the bike to move well above 3.5k rpm, a tiny bit of popping on decel and decent/slightly lean looking plugs throughout except at 1/8th throttle, maybe I need to raise the floats slightly? They've all been meticulously set at 22.4mm and have nice stock needle valves.

Any more tips? I guess I'm just confused as it seems like no one ever changes pilots until they've moved to pods but maybe I should experiment with them as well? I'll dial in the mains first and continue from there so we'll see.

Thanks!

Josh

[posplayr]

Well I shouldn't be up at stage 3 with the stock airbox and a K&N drop in filter. I think I'll go back down to 120s and see where I'm at. I took it out last night and tried to look at the plugs but it was dark. WOT to redline in 1st or 2nd is great in the midrange and then stumbles/surges at 7k and 8k and does not pull as strong as with the 117s.

I'm at a bit of a loss. Maybe my floats are causing some of this? If I could hardly get the bike to rev with 117.5s and the needles at the 3rd position and then moved to them to the 5th position and got the bike to move well above 3.5k rpm, a tiny bit of popping on decel and decent/slightly lean looking plugs throughout except at 1/8th throttle, maybe I need to raise the floats slightly? They've all been meticulously set at 22.4mm and have nice stock needle valves.

Any more tips? I guess I'm just confused as it seems like no one ever changes pilots until they've moved to pods but maybe I should experiment with them as well? I'll dial in the mains first and continue from there so we'll see.

Thanks!

Josh

I was gonna post before, but assumed someone knew your configuration but with your bike and K&N pods (not the k&N dropin), a DJ kit , 138's ,3rd clip, DJ needle of course, 47.5's on the pilots will have you running well.

[Rudeman]

There's a particular order or progression to follow when jetting CV carbs that differs from VM carbs. I think you're supposed to get the mains right first then the needles and then the pilots. I think it is because (except for the enrichening circuit), all fuel normally passes first through the main jets regardless of which circuit you're running on. If you get the pilots right then resize the mains it will throw things off for the idle circuit.

I would leave the floats alone on a stock motor; set them to factory spec and leave them be.

[Tom R]

I didn't read your post too carefully - but even without pods, 47.5's shouldn't be ruled out for your setup. From what I've seen, Canadian spec models came from the factory with 47.5's.

[Tom R]

Without getting into the Bernoulli principle - and of course I could be wrong, but I don't think the idle or pilot circuits actually stop spraying gas at wot, they just pale in comparison to what sprays out of the needle jet. With that in mind, I'd think you'd want to have your pilot jet settled before you select your main jet.