Shimming CV34 needles?

These CV34's are off an 1982 750-4. I'm not sure if the needles are the adjustable type or not, and I'm not even sure this is something I want to do, but is there a website somewhere that details the process?

Why do you want to shim them? Did you modify the engine?

I'm not sure I want to, but I've been considering going to pods and drilling out the back of the mufflers. I asked around about similar setups to what I'm considering and this came up. One person said to just go to 135 jets (from my stock 125 jets) and screw the pilot needle in 1 turn. Another said to do the same thing, but to shim the needles up by .030" I'm not sure either of these will work, so I'm approaching them as ballpark ideas. But I don't know much about shimming needles, if I even decide to do so.

If you go to pods you will have to do a lot more than that to the carbs. They are set up for use with the vacuum resistance of the air box and the lifting diaphragms will not work right with out some other carburetor modifications. In 1982 in the US none of these carburetors had adjustable needles. The stock jet size on these was 110. On CV carbs you have to go up three sizes just for the pods, and one more for a relieved exhaust system. Plus the mods to the slides and so forth. If you have no experience with this than you can do some major damage.

Damn dream killer. If you need to raise your needles you can get really small washers at hardware stores. They are tough to find. You have to go to like an ace hardware. You might have to go 140 on the mains. I am not sure as to the slide mods otakar speaks of. I assume its drilling out the slides. which you could over do but I'm sure someone would have some answers.

If you are going to use washers and not shims, than you better measure Exactly how much you are raising each needle. They must be within .002 of each other otherwise each carb will run differently once you go past about 2500rpm. I have built a lot of these carbs. Even though they are quite forgiving and they can be better than smooth bores on the street, it is also quite easy to make them into nothing more than scrap metal if you don't know what you are doing. When I build them I run them on a vacuum table to make sure they are synchronized threw the entire power band.

I've done a lot of work on car carbs, but I realize of course that these Keihen CV34's are different, that's why I'm asking so many questions. Just trying to learn. And I do appreciate the responses!

By the way, I checked my secondary main jets and they are 125's. The primaries are 62's. The book says this is right.

So are we saying that pods simply won't work on these carbs with jetting changes alone? I've read posts where people disagree, but I can't seem to get any ballpark jet numbers.

Polkat,

You've got your heart set on cutting this bike up... How does it run now with stock air box and exhaust?

My 2 cents:
Drilling the exhaust and jets will set you back. A good 4-1 exhaust with performance baffle and pods might be worth some decent top end power. You'll need a stage 3 jet kit with adjustable needles and proper size jets. Will cost a few hundered bucks and will take a lot of test and tune to get it right. Anything short of this will likely yeild sub-stock performance.

I've been down the road of jet and exhast drilling in my younger days and no one was going to talk me out of it...

davel wrote:

...Will cost a few hundred bucks....

That's so unfair, hitting Polkat right square in the wallet! :laugh: :laugh: :laugh:

Good Fortune!

Well, I can't see paying a few hundred bucks for a handfull of jets and needles, even if they are gold plated. But I'm getting the picture here, so I'll fall back on my airbox mod idea.

polkat wrote:

Well, I can't see paying a few hundred bucks for a handfull of jets and needles, even if they are gold plated.

The few hundred bucks inclueds a good 4-1 exhaust with performance baffle. This item will be responsible for most of your power gains IF the carbs are retuned correctly.

More importantly - How is the bike running now? That bike should get-up-and-go in stock form if it's in a proper state of tune.

Often, when an engine falls out of tune, guys start modifying parts rather than concentrating on re-tuning of the stock engine. This leads to all sorts of problems. Ask me how I know...

The cheapest route with the best result would be to figure out what's wrong with its current state of tune. This might cost nothing and you'll get considerable performance gains.

First of all, In 1982 Kawasaki made the E3, H3, L2, R1, models of 750/4s They had different carburetors and different jetting. It would help out so much if we did not have to guess at what we were trying to fix. Heck, they did not even have the same BRAND of carburetors. Some had Mikuni single butterfly single jet carbs (the good ones), some had dual butterfly, dual jet carbs (the worst ones), and some had Keihin's (eh- So-So). This is sort of like calling up A doctor (not your doctor) on the phone and saying Hay doctor I have stomach cramps, what can I take for it. What the heck, the doctor wont even know if your'e man or woman. If you are pregnant or you were shot in the stomach. Sometimes, JUST sometimes, full information would help since we do not have a profile on the bike. :blink: There is nothing in the signature block to go by. So all I can say is this, "Take two antacids try to have a really good fart, and call us in the morning" :silly: Until we can see the full picture and have a clear idea of what we are dealing with.