question about carb slide springs

[79XS11F]

Fair enough... so as said the "velocity of the air going past the fuel opening is controlled by the position of the carb slides". This is the point that I'm trying to make. They should all rise and fall at the same rate or the fuel / air delivery to the engine will be affected. Different cylinders will be running at different fuel / air mixtures until all the slides are at the top of their travel. I just don't think stretching out the springs to be all the same length will correct the spring rate. I think spring rate is a very important factor if the intention is to make all the carbs function the same and provide a smooth and consistent fuel / air delivery across all 4 cylinders. There's no doubt that having all the carbs operate the same is a good place to start when fine tuning. 30 year old springs that have been under a load all that time are not likely to delver the same spring rate as when new or the same spring rate as each other. Of course when it's all said and done it is likely a moot issue unless all the cylinders are also demanding the same amount of draw through the carbs which would be dependent on ring condition and valve condition / adjustment and for that matter exhaust system condition etc. In my mind , as twisted as it is, those springs and the resistance they are designed to delver to the slide are an important element in the whole fine tuning scenario. If their only job was to return the slides to the bottom position we wouldn't be having this conversation... would we?
Rob

[latexeses]

I think this discussion is "Phase"ing back and forth with a discussion started by 3Phase about clutch springs..."I see lots of noodles"...

Wow, if this discussion is about the diaphragm springs in the carbs, mine have to be way out.

I measured the diaphragm springs in my 79SF just a bit ago..
#1. 3.65"
#2. 3.61"
#3. 3.64"
#4. 3.57"

That is measured relaxed, on their sides.

I thought that was pretty close until I read Ivan's post about the 5.75" spring length.

3Phase mentioned his spring length varried between 4.93" - 4.97".

Are mine that shot??
Guess this means another trip to the checkout counter.
Is there a different spring rate for the standard vs. specials?

Rodger

[bikerphil]

Guess this means another trip to the checkout counter.


Rodger

Good luck finding them anywhere.

[3Phase]

I think this discussion is "Phase"ing back and forth with a discussion started by 3Phase about clutch springs..."I see lots of noodles"...

Coincidentally, Ivan and I seem to have stumbled upon the same acorn at the same time.


I had been searching high and low for spring and clutch specs and Aurthur Godfrey's Lipton Soup pitch and his search for any trace of chicken in the soup came to mind.

Regards,

Scott "Maybe a chicken once walked around the pot."

[Ivan]

I think this discussion is "Phase"ing back and forth with a discussion started by 3Phase about clutch springs..."I see lots of noodles"...

Wow, if this discussion is about the diaphragm springs in the carbs, mine have to be way out.

I measured the diaphragm springs in my 79SF just a bit ago..
#1. 3.65"
#2. 3.61"
#3. 3.64"
#4. 3.57"

That is measured relaxed, on their sides.

I thought that was pretty close until I read Ivan's post about the 5.75" spring length.

3Phase mentioned his spring length varried between 4.93" - 4.97".

Are mine that shot??
Guess this means another trip to the checkout counter.
Is there a different spring rate for the standard vs. specials?

Rodger

Mine is an 81 and the resting length was right at 5" before the stretch. They extended rather easily to 5 3/4", which I suspect was pretty close to the original length. I gave it the extra 1/4" since I imagine they will relax again rather soon.

In my mind , as twisted as it is, those springs and the resistance they are designed to delver to the slide are an important element in the whole fine tuning scenario.

I am with you there. Thus I stretched them to see what kind of difference it would make. My accuracy probably isn't up to snuff, but it is just to see if it will help. Ideally one would make a loaded adjustment, as they do with valve springs. Not knowing the actual rate intended for these springs makes it kind of a crap shoot, but placing a heavy washer on them or something would up the accuracy. Somewhere it was suggested to use a weight hanging from them to make them equal, which should work as well. The next day it is decent for riding and I can get the bike fully warmed up without freezing my gall bladder solid, I intend to find out whether or not the stumble has changed. If so, I can pull the carbs in about 4 minutes so it won't be a big deal to equalize the springs, and resynch the carbs.

[latexeses]

Ivan, 3Phase...

I counted the number of coils on my springs ----27 coils with closed ends. Spring dia.=.645. Wire dia.=.032. How does that stand with your springs? I know, it is hard to tell when they are installed. Sorry.

They look as though they are made of nothing more special than music wire. Probably made from a 1952 Buick. A magnet really likes them.

bikerphill...

Man, you are right about that. I ran across a outfit that specializes in small runs of springs. I am going to check to see if they consider a "small run" as anything under a ton.

Rodger

[TopCatGr58]

Hey Latex,

Slow down, the springs for the 78-79 ARE different than the 80-81 series, the slides are a different diameter as well, etc.!! I don't have any specs on the springs either, but they are a different size in diameter, and possibly also in length, so perhaps some other folks with the early model carbs can measure theirs. I have a set out in the garage, but it's late here, and SWMBO is calling me, so I can check them out tomorrow and let you know what I find for them!
T.C.

[3Phase]

1980G Slides and Slide Springs

Ivan, 3Phase...

I counted the number of coils on my springs ----27 coils with closed ends. Spring dia.=.645. Wire dia.=.032. How does that stand with your springs? I know, it is hard to tell when they are installed. Sorry.

They look as though they are made of nothing more special than music wire. Probably made from a 1952 Buick. A magnet really likes them.

Here you go: 1980 XS1100G carburetors with SG slide needles

Slide Spring Length : 4.97" 126.238mm
Slide Spring OD : 0.9285" 23.5839mm
Slide Spring ID : 0.845" 21.463mm
Slide Spring Wire Diameter : 0.040" 1.016mm
Slide Spring Number of Coils: 35

Slide Length: 2.149" 54.5846mm
Slide OD : 1.139" 28.9306mm
Slide ID : 0.945" 24.003mm


Some pictures



Regards,

Scott

[latexeses]

TC...

I'll pull in the clutch. Caught me off guard with some of the measurements. I guess I was under the assumption that the carb internals were the same. I should have known better. Don't assume....

BEWARE OF SWMBO durring the hollidays. VERY testy. For any number of reasons. You need two jobs to afford all of the paraphernalia that makes XS1100 riding possible----Like jewels and furs....

Mine has her Christmas lights up here, so I am out from under the gun. For the moment anyway. The house looks much like the Grisdwald house-- at least on the inside. Outside, got a ways to go.

Thanks,

Rodger

[jrplumber1]

Where?

Where is a good place to get these springs?
Im thinking of doing a carb job and what better time to do them then when I have them apart!

[TopCatGr58]

Hey Latex,

I just measured ONE of my springs, didn't measure them all because the guy I had loaned them to torqued the caps/screws down so tight, took me 5 minutes to get just the ones for 1 loose!! But your measurements are right in line with what I found, about 3.5" long. Yes, they are shorter than the 80-81 series, but that's just the way it is!

As for sourcing them, I don't know IF they are still available, etc.!?
T.C.

[Yahman]

Spring part number 2H7-14933-00-00 fits all 78 and 79 XS1100 at $4.80 each (powersedge.com).

Spring part number 3H5-14933-00-00 fits all 80 to 82 XS1100 and XJ1100 at $18.11 each (powersedge.com). Also fits 88 to 90 FZR400 models.

Larry

[Dan Hodges]

Carb Slide Springs & Needles

As you folks might recall I had mucho problems during my dyno test with my A/F ratio going fat at 2500 rpm causing a bad stumble untill it reached about 3,000 rpm after which it got better but went fat again at 4500 rpm, cleared up at 5500 rpm and remained at a 13 to one ratio to 9,000 rpm where it was shut off. When riding it you could whack it WOT at 2,000 rpm and it would pull like a truck in 5th. gear untill it reached 2500 rpm where it gagged untill it reached 3,000 rpm and then it bolted. Bone stock with the stock jetting I had none of these problems however when I did my build up which consisted of the 1179 kit, Megacycle cams, ported head and a Super/Trapp header with a 2.5 inch muffler core the thing ran like crap at 2500 rpm when you whacked it but ran like a champ after it passed the 3,000 rpm zone. To make a long story short, I tried several spring combos including a set of V-Max springs which are two inches longer and much stiffer and this cured the problems with the stumbles but cost some hp in the mid range because the slides were not opening quick enough. The stock vacum holes in the slides are .093 in diameter and reducing the diameter of these holes has the same effect as using stiffer springs and I tried this too but wasn't satisfied with the results. I also tried shortening the plastic donuts by shaving them .025 to lower the needles and this also cured the low end stumble but caused it to go lean from 3,000 rpm to about 4500 rpm. Yes, the floats are set correctly. Adding a high flowing pipe, pod filters, cams with more overlap and more cubic inches all cause the slides to open more quickly raising the needles causing it to go fat down low. The needles in the 81 Specials are too short with a steep taper and the Standards are almost as bad. Ultimately I bought a dyno-jet kit which contain needles that are longer and have a longer more gradual taper. I bought new Yamaha OEM slides and a new set of slide springs and installed the kit per stage II recommendations, #190 air pilot jet and # 128 main jets and it's dead nut on with no stumbles and it picked up two more horsepower on the top end. Mention is made that the DJ jets do not correspond to Mikuni jets as the DJ jets are listed by hole size whereas the Mikuni's are listed by flow size. A #128 DJ jet is comparable to a Mikuni # 120 jet. If your combination is stock, the stock jetting and needles will work but even in stock form the Dyno-Jet stage I kit will make it run better especially down low and in the mid range and the DJ needles are adjustable. Maximan's friend built a 1196 with a Web intake cam and using the stock pipes made 85 horsepower using the DJ stage I kit and it was dead nut on with no dips anywhere in the power curve. Of course there is always several ways to come up a combination but in my case the DJ kit was the best $125.00 I ever spent and I wished I had used it from the git go as I almost went back to drinking and smoking again messing with them carburetors. The DJ kit is no longer available for the 78-79 carburetors. Attached are pictures of the stock vs V-Max springs and the stock needles vs the DJ needles.

[79XS11F]

Hey Dan .. How much of a roll, if any at all, do you think having new springs played in the final fixing of the issue? I happen to have DJ jetting for my 1179 bike that came with the K&N pod filter kit. I pretty much bough the kit for the jets.
Rob

[Ivan]

Thanks for the input Dan.

After getting a chance to put 100 miles on the scoot last week, the spring lengthening did help, but not as I had hoped.

Before, the bike used to fall on its face when I would get under 3k rpm. It had nothing. Then I put some bigger pilot jets in and retuned. It was mildly better, and wouldn't die if I got out of the clutch early, but it wouldn't pull either. Now with the springs lengthened, it pulls. Still, when I hit 3k, it feels like afterburners kick in.

From what you are saying about the Dynojet kits, I probably need to get one.