Shimming CV carb needles – never fails to amaze…

[Nessism]

Ed's at Sea level that's one thing....

Also I believe that motor is made up from Parts, the head is not the original & neither are the Cams & I don't think the carbs are off an S model so I guess it's possible that could also require a slightly different setup. The exhaust is also off a 781000 from memory, all things that could have some effect.

I agree with Ed though, lifting the needle by a couple of washers does seem to make a good bit of difference round here on the couple of stock bikes that I have played with.

Dan

Thanks for defending me Dan but no need. The head on this bike is from a 1000G, which is identical (same part number) as the 1000E and 1000S head for 1980. The cams are likewise from a 1000G, which again are identical to the 1000S parts. The only thing on this bike that is not 100% stock is the carb jets which I think are K&L parts and the exhaust pipes which are regular C/N/E pipes. The jet could have something to do with the issue but I doubt it.

Keith's memory is foggy, or maybe he's never ridden a bone stock 1000 with CV carbs on a cold morning.

[tfb]

What a glorious-looking machine!

[posplayr]

Ed,
Real nice. I have not see this machine close up but if it is anything like that GS750 you did then I know it is immaculate. I know enough now that this kind of detail only comes from the experience of the other builds you under your belt. Also I don't think you sent a ton of money on PC, so most all of this was refinished DIY but with professional results.
Congrats
Jim.

P.S. I have been planning to shim the CV's on my bone stock Ca 81 GS750. It runs a little lean as well.

[KEITH KRAUSE]

Ed, like I said, I'm not trying to argue. Nothing to defend against. Nothing intended as an attack on your knowledge.
I simply find it hard to believe Suzuki sold all those bikes and eveyone had to go through what you said you do just to get them rolling. Their jetting could be off but not so much as you believe. Nobody would buy the bikes. I certainly wouldn't.
I still think there's other factors involved here that worsen the existing condition and create the need for your suggested change, that's all.
See?? Lots of smilies.

[Nessism]

Ed,
Real nice. I have not see this machine close up but if it is anything like that GS750 you did then I know it is immaculate. I know enough now that this kind of detail only comes from the experience of the other builds you under your belt. Also I don't think you sent a ton of money on PC, so most all of this was refinished DIY but with professional results.
Congrats
Jim.

P.S. I have been planning to shim the CV's on my bone stock Ca 81 GS750. It runs a little lean as well.

Thanks Jim. Shim those needles, you will be amazed what 1 mm will do.

Something to keep in mind regarding this mod is that the needle height is dictated by the spacer on top of the needle clip. This is contrary to what some might think but you have to realize that there is a spring under the needle clip that pushes up so how far up the needle goes depends on what's above the clip, not what's below.

Radio Shack sells a bag of washers that are the proper size from what people have said. What I did was take some washers with the proper ID and stack them on a small screw with a nut, and then chuck up the assembly in a drill motor to spin them so the OD can be reduced with a file. Works great if you are too lazy to drive to Radio Shack.

Regarding my bike, I used POR-15 paints on most parts after bead blasting in my ebay procured blast cabinet (great purchase). The paint seems pretty tough, particularly the Hardnose stuff which is two part catalyzed. One other great purchase which made this restoration easier was a Caswell Plating zinc home plating kit. This kit was not cheap but it's really nice to have nice shiny hardware to use when bolting everything back together.

[renobruce]

Beautiful job, Ed. Is there some paint missing on the "I" on the tank, or is that just the pic?

[salty_monk]

Unless Ed's had an accident with it them that's just the picture.
I have seen this bike in the flesh and it's about as perfect as could possibly be done DIY.
Ed would be able to point out some tiny flaws in the paint or whatever I'm sure but it's remarkable considering it was painted outside. Ed has a very critical eye, you have to look hard to see things he picks up on!

[doctorgonzo]

Unless Ed's had an accident with it them that's just the picture.
I have seen this bike in the flesh and it's about as perfect as could be done DIY.
Ed would be able to point out some tiny flaws in the paint I'm sure but it's remarkable considering it was painted outside. Ed has a very critical eye, you have to look hard to see things he picks up on!

I think Ed was potty trained at gunpoint, as all good engineers should be.

[Dave8338]

The bikes a turd!

Yes the needle mod is a must especially if you ride early or late in the season.















I LOVE the bike, ED!

[82Shafty]

I'm going to have to check out one of mine because my '82 can be fully off choke in about 30 seconds on a 35 degree morning, yet doesn't run rich when it is warm. Float heights were set to spec. All stock as far as I could tell.

I'll have to see if one of the three before me has done this mod already.

[Don-lo]

In 82 or 83, one of the magazines (Cycle, I think) had a mid-size sportbike shootout featuring the GPZ550, Seca 550, VFR500, and Katana 650. The Katana finished near the bottom of the comparison because of its poor carburation. At the end of the article, there was a small side box explaining that they shimmed the needles afterwards and it completely transformed the bike, so much so that it may have won the shootout in that form. I will try and find the article and scan it.

I think perhaps Suzuki designed the carburation to the ragged edge of lean, and then machining tolerances were enough to leave it running poorly.

I'm also still trying to figure out why they designed such poor cam degree numbers for my GS1000.

[jimfj]

Kudo's to you and your bike Ed.

I too, shim the needles on every CV carb I encounter and the results never cease to amaze. I buy nylon washers at the local hardware. I belive they are #4 size metric. It takes 3 of those to make up the thickness of the stock spacer. I usually put two on the post so I'm shimming down 1/3 of stock. My 850 and 1100 both responded very well to the change. The 1100 might do better with one more washer removed. I haven't tried it though. Too darn cold here to shovel snow, much less ride.

Jim

[renobruce]

I'm not doubting anyone's results, but how would shimming the needle affect the choke and/or pilot circuit?

[Steve]

I'm not doubting anyone's results, but how would shimming the needle effect the choke and/or pilot circuit?

OK, I just have to ask ... do you mean Effect or Affect?

Yes, there's a difference.

Shimming the needle might Affect the "choke" and/or pilot circuits only in that you will not need to use them as long before you can safely ride the bike after starting it. You will richen up the mixture enough that you can turn the "choke" off sooner and it will still run well. It won't really Affect the actual circuits, just ease the leanness of the transition into the needle circuit.

On the other hand, there is no way that shimming the needle can Effect the "choke" circuit.
Used as a verb, "Effect" means "to make it happen", so there is no way that shimming the needle will cause the "choke" to be ON.

English lesson over.

.

[renobruce]

I meant affect. The choke bypasses all other circuits. With the choke off and the bike at idle to about 1/8th throttle, the needle does not come into play.

I can see how richening the needle might make it run better when the carbs are on that circuit and when in transition from the pilot and to the main, but no other time. If we are to use the logic that the bikes are set lean from the factory and are cold blooded, then richening the pilot circuit would be the logical fix I would think. But then again, doesn't lean = hotter and rich = colder?