washers on needles

[rahlo1]

 the washers on the carb needles is a great mod. i put 2 #3 washers on them this weekend and the throttle response is better from 3000 rpm to 7000 so it gets to the sweet spot faster. i also have a 14t sprocket on it so that helps. if anyone is thinking of doing this mod do it its simple and takes under an hour 

[The Buddha]

Yea ... but please post more details, like what year etc etc (I know yours is 01+ ... but those that dont know ...)
Yea #3's the shnitz ... but 89-00 #4 needed ... 
Cool.
Buddha.

[rahlo1]

oh yeah sorry about that. its a 05 all stock except for the sprocket which i put on a month ago.

[Ry_Guy]

Did the plugs look any darker from your mod?

[nascarkeith]

Yeah I put them on my 06.  It helped a lot.  My K&N drop in and 15 tooth sprocket came in today.  I look forward to trying those out.

[The Buddha]

You 2 kids have the right idea. 1 small mod at a time and I guess you're keeping proper notes no ... well, gstwin is a online note pad, I know what you did, and so do you.
Cool.
Buddha.

[respite]

Ill bite. What exactly is a #3 washer? Is there an sae or metric size which equals a "#3"?

[rahlo1]

"Ill bite. What exactly is a #3 washer? Is there an sae or metric size which equals a "#3"?"
just go to any hardware store and ask for #3 washers they will know what your talking about, they are very small stainless washers.

"Did the plugs look any darker from your mod?"
i have not checked the plugs yet, i will in a week or two.

"Yeah I put them on my 06.  It helped a lot.  My K&N drop in and 15 tooth sprocket came in today.  I look forward to trying those out."
let us know how the k&n works. will you be removing the restrictor?

[pkhoff]

I'm curious about why the 3 jet carbs need #3 washers and the 2 jet carbs need #4 washers.

I have a '94 and the Buddha sent me 40 pilots, 125 and 127.5 mains and washers, (not sure on the size).

I put in the 40/125 with one washer until I got my K&N drop in, then I added switched the 125's for the 127.5's.  I went to the local hardware store for #4 washers, (I wanted to add 1 more).

I checked two different hardware stores and they both had #4 washers in brass only, and they were smaller than the ones the Buddha sent to me, (Buddha's were stainless). So I put in two of the brass #4's.

I am still having problems, bike is not running right.

I have a '94 with stock pipe, K&N drop in (no restrictor), 127.5 mains, 140 pilots, 2 #4 brass washers under each needle. I have disassembled the carbs completely and cleaned them thoroughly, replaced all Orings. Idle screws are 3 turns out.

The bike starts easily and runs well at all throttle positions and rpm's up to ~40 mph. Starting at ~50 mph up to about ~70mph it surges (bucks and jerks is a better description)

This happens only if I try to hold a steady speed, if I am accelerating it runs fine. If I run 75 mph or faster there is also no problem.

I am going to try adding another washer under each needle, as it seems to me that it is lean at part throttle. I am thinking that it is only slightly lean since it is fine at low speeds but at higher speed where I'm using more fuel this problems occurs.

I have not sync'd my carbs yet as I have a broken nipple on one of my carb tops, but visually the throttle blades appear to be close to the same.

I've been pulling the plugs about every 50 miles and they always appear a little lean.

Has anyone else had a problem like this?

[rahlo1]

sorry cant help on that one maybe buddha can

[quiktaco]

The bike starts easily and runs well at all throttle positions and rpm's up to ~40 mph. Starting at ~50 mph up to about ~70mph it surges (bucks and jerks is a better description)
This happens only if I try to hold a steady speed, if I am accelerating it runs fine. If I run 75 mph or faster there is also no problem.

I'm pretty sure this is due to a lean condition.  At higher speeds, the throttle is open more at a given rpm than at lower speeds (correct me if I'm wrong), so I'd say it may be your main that needs to be upped a size.  If it were at lower speeds doing this, then you may have needed to raise the needle slightly more.

Hopefully this helps.  Can anyone else confirm this?

[theUBS]

Yea ... but please post more details, like what year etc etc (I know yours is 01+ ... but those that dont know ...)
Yea #3's the shnitz ... but 89-00 #4 needed ... 
Cool.
Buddha.

I have a 2000.   What would you recommend for it?  40's and 125's?  One #4 for each needle?   I know that's not really the ultimate in performance for the GS, but all I'm really looking for is smooth throttle response and fewer idle issues.  I'll keep SOME of my economy.  Thoughts and recommendations?

[pkhoff]

quicktaco, thanks for the input. I'm pretty sure it is a lean condition.

Throttle response is excellent, smooth at any throttle position, can cruise steady at any speed up to ~40.  Say, for instance, 1/2 throttle in 3rd gear is 40mph, I shift up to 5th, I have to reduce throttle slightly to maintain 40 mph, shift to 6th, reduce throttle a little more to maintain 40 mph.  Now I speed up to 65 mph, I increase throttle up to around 1/2 throttle and try to maintain 65 mph, bike begins to buck and jerk. I open throttle to around 3/4, bike accelerates up to ~75 mph, I reduce throttle slightly to maintain 75 mph and have no bucking or jerking.

So my line of thinking is at the higher speed, same throttle position, the load is higher due to wind resistance, so I need more fuel.  Seems as if there is not enough fuel at part throttle, but at nearly full throttle I have enough fuel.

I don't know if a larger main jet will give me more part throttle fuel or if that is a function only of the needles.



I added a third washer under each needle and went for a test ride. Symptoms were reduced somewhat but still there. I pulled over and put the K&N filter restrictor on.  Part throttle cruise was almost perfect. I haven't pulled the plugs to check them yet.

I don't want the air filter restrictor to be part of the final solution, so I have two choices, as I see it: add another washer for a total of 4 (seems to be getting excessive) or go up a size on the mains (as you suggest).

In the jetting wiki and from other posts, my intake and exhaust combo should take the 127.5 main, so i have resisted going up another size. I think I'm going to do it anyway as I seem to be running out of options.

Oh, and it started harder this morning (I did the testing last night). Usually I choke it and it goes to 4k in about 10 seconds. This morning it didn't start right away on full choke, I gave it half choke and blipped the throttle a few times, it idled up to about 4k after about 30 seconds.

[quiktaco]

A larger main will give you more fuel at part throttle, say above 1/2 throttle or so, but it doesn't have as much of a change as the height of the needle.

You may have it perfect with one size large main, and 2 washers on the needle.  I have the lunchbox filter, so I don't know first hand, but I think the K&N drop in is still a pretty high flowing filter...especially compared to the stock drop in.  Also, if you are at or near sea level, then the air pressure is higher which would cause the need for a little more fuel.

I'd try one size larger on the main if you just want to test it that way.  If you want to do a plug chop at full throttle, then that would tell you for sure.  If you don't know how, do a search, cause there's a lot of posts about it.

Remember that the matrix is only personal experience.  It's not going to be 100% right every time.  And some peoples' thoughts of right on, might be broader than other's, so some information on there may be slightly off.  It's always a trial and error thing when rejetting.  I'm still working on mine to get it perfect (partly because I keep making new exhausts for it)

Hard starting can be attributed to a lot of things.  It could have just been a damp morning, and the moisture in the air caused it.  It also could be that your plugs are sooty and need a few turns of the starter to heat up enough to get and adequate spark.  Also could be that your float level is really low.  I'd say that if it doesn't happen often after this, then it was probably just a damp morning.  If it's continually happening, then your plugs might be to blame.  If anyone know of some other reasons, please add.

[pkhoff]

I am going to go ahead and try a 4th washer on each needle, and take the filter restrictor out, for testing purposes. I'll order a set of 130 mains as well, then do more testing with those in and different washer configurations.

I am at ~700ft above sea level. I see your point about different people's idea of "right on" could be different. I still haven't synced my carbs yet, not sure how much of an issue that is. My valves are all in spec. I do have an ignition advancer by Bob.

I read your muffler building thread with great interest, I don't have a welder of my own and it's been a while since I did any welding. I would like to put duals on my bike at some point and utilize mufflers similar to the one's you've built.

The morning that it started hard was similar to the previous morning, it also started hard that afternoon when I was leaving work, and then this morning as well. I last looked at the plugs ~50 miles ago. They looked a little on the lean side at that time. They have ~250 miles total on them.

[quiktaco]

4 washers is a bit much, might make you very rich in the middle.  I have 2 washers and have a lunchbox and exhaust.  Good for testing though.  700 feet isn't too high, so I'd say that you're getting a descent amount of air in, which might be contributing to your problems.

What kind of plugs do you have?  Champions?  If you do, trash them and get NGK's, I had Champions for about 5 days until they started giving me all sorts of problems.  Don't know for sure if it's the plugs that are causing the hard starting, but it's worth a shot to pull them and take a look after all this adjusting of the carbs.

[pkhoff]

I agree, 4 washers sounds like a lot. I'm wondering if I have something plugged causing the midrange lean condition. Since adding a washer helped, and then adding the restrictor helped even more, I'm sure I need more fuel in the midrange.

I'm hoping the 130 jets with a washer or two under the needles will fix the midrange leanness without making me too rich on the top end.

I forgot to mention that my floats are right on, as tested with the clear tubing method.

I am running splitfire plugs at the moment, I do have a set of the stock NGK's.

[quiktaco]

When you get the 130's, I'd start with those and 2 washers to see where you're at.  1 washer would be too drastic, since you're saying it's better with more and the 127.5's.

For sure, if adding the restrictor helped, then that means that you're getting too much air and not enough fuel.  The bigger mains should help for sure.

Haven't heard anything about splitfires with these bikes, but I'm sure they're good.  Just check them to see if they're sooty or not.

[The Buddha]

Holee cow ... I totally missed this ...
I'll read it and get back to you Pkhoff ... sorry ...
Cool.
Buddha.

[The Buddha]

OK you have a broken vacuum spigot. You have to close it before doing anything, that is letting in air making it lean.
If you fix that, then washers, no more than 3, start checking float level and more of the fundamentals.
Trying to cruise and you have issues, but open throttle and it behaves = lean. Its called lean surge. Maybe toss a sock in the filter with the cuff wrapped around the restrictor.
I am thinking we need to cut down your air flow a shade to compensate for the lack of outflow. The mismatch in airflow capacity can do this dual nature thing ... its rich in 1 spot and lean elsewhere ... and goes right back to rich when you get past that ... which is atleast 1 reason I hate stock pipe with WFO filters. My eliminator totally misbehaved like that till I put a pipe on ...
Cool.
Buddha.