bs34 carb mods

keep reading about having to modify bs34 carbs if you're running pod filters..this is news to me..anyone done these mods as of yet..just tore my carbs down and cleaned and jetted them..haven't fired it up yet so would like to know what to expect..thanx in advance..

apparently there is a fellow trying to stur up business with these claims of insufficient vacuum on the older bikes to pull the diaphragms up high enuff..you send him your carbs ,pay and he does the secret mod ...:lol: you will need to increase the jet size to eliminate running lean

As much as I do not agree with WG on much we do agree on the mods. With 160 mains you might be able to hit 100mph on a bike which was able to do 120mph with an airbox and 127.5 mains before. Ive been doing this for thirty plus years and have learned the long way and hard way. the FACT that a stock BS carb will not run properly without an airbox is no secret. Knowing what to do to make them run right is the trick. You wont do any damage by not modifying the carbs,you will just loose about 15-25% performance.

I've seen this too. Otakar, could you outline what mods have to be done to the carbs?

T_Dub wrote:

I've seen this too. Otakar, could you outline what mods have to be done to the carbs?

it is pretty simple really. you just have to connect all of the carb inlets to a large box and put a filter in there. that is the secret mod to make the carbs work well:P

Total Re-Jetting including Needles, Shimming of certain components, and some Machining. This also includes complete and I mean COMPLETE disassembly, and cleaning. I dip all components dependent on material from which they are made in custom solvents which I blend myself. I also polish the outside float boles and diaphragm covers (If they are not Chromed). If you prefer the boles and covers black, gold, or Titanium colored that is $25 extra. No I do not use a spray can to pain them i use "Polane-B" Industrial Polly-Urethane out of a spray gun and it than is baked on. The Paint is impervious to all non Chlorinated solvents, and can withstand short term exposure to those also.
Here is the set I did for my bike. The VM33SBs are for sale on eBay right now because I actually prefer the BS33cv carb over them.

What 88alltrac stated is also true. But than you just have the factory performance and no more.

Just you have an idea, here is a picture of the two custom jet needles I use in my mods. The one on the left is the stock needle, the one in the middle is the one for better cruising economy but still a hi top end and the one on the right is for "to hell with the gas millage give it all shes got". :silly:

I'm not sure What I did but here is the picture.

So basically a jets and needles and a good cleanup and she'll be good to go? Where do you get those nutty needles? Sounds like I'll want the middle one on my KZ650-810. Could you recommend a setup for that? I'm good at fixing carbs, but I have no experience at all with jetting things. She'll have gpz cams, pods and a pipe.

Yup tat's all plus the machining. I have the needles custom ground from a 3mm, 8 series Harley needle. I have no idea what it will act like on a motor as small as a 800. Never tried it. These are calculated for engines 1000-1200. Like DynoJet, I do not sell the needles.

i've contacted jeff at z1 and he told me to just remove a little of the rubber around the inside of the filter body as it blocks an air passage..and was also told that k&n's do not have this problem..