Leaking Carb

Fired the motor up for the first time today and noticed fuel leaking out of the throat on the filter side of the #2 carb. Do I have a stuck slide or is it in the float, don't know much about carbs obviously. Also could anyone tell me the float height for a BS34. What jets should I be using for a stock CSR 1000 with aftermarket exhaust and pods.

You don't say if the bike has been stood for sometime or the carbs rebuilt/cleaned...

If they are BS34's and you have pods fitted, remove the pod and push the slide up with your finger. Let go and the slide should return in one smooth movement. A mirror might help to see what's going on. As far as float height goes for the B34's, mine are 18.6mm +/- 1mm. This is for a KZ1100 ltd though, so check out the web for your bike. There may be a difference. Here's a link to a pdf by Ed Ness regarding the rebuild of Mikuni Carbs. Although it's aimed at Suzuki owners, it's very informative and features B34 CV carbs. Well worth downloading... COPY AND PASTE THE WHOLE LINK

www.mtsac.edu/~cliff/storage/gs/Mikuni_B...Rebuild_Tutorial.pdf

Re-jetting for exhaust and pods, the concensus of opinion seems to be an uprating of the main jet and "sometimes" the pilot jet, along with re-clipping the needle. I've actually gone the other way with my bike and returned to the stock air box and stock exhaust. Main 120 to stock 117.5 with stock pilot of 37.5 This is a subject which in my opinion requires a degree of experimentation with jetting and needle height, and there are many on this forum with far more practice than I have regarding uprating carbs, hopefully someone will come along...

I bought the cards from my local salvage yard, he sonic cleaned them for me but they have not been rebuilt. I assume they have been sitting for quite a while as I have had them for a year and who knows how long he had them before I bought them but for 100.00 cleaned I thought it was a pretty good deal. He sold me a complete motor minus carbs and exhaust for 400.00 and when I took the valve cover off to look at the cams for wear and changed the oil the thing was spotless so I trust him and what he sells, I just am not sure what bike theese carbs came off of and want to set them up properly for my bike before I can do any damage.Thanks for the info, I will tear into them and check the slides first.

kool4kawis wrote: Fired the motor up for the first time today and noticed fuel leaking out of the throat on the filter side of the #2 carb. Do I have a stuck slide or is it in the float, don't know much about carbs obviously. Also could anyone tell me the float height for a BS34. What jets should I be using for a stock CSR 1000 with aftermarket exhaust and pods.

Fuel may have also entered the crankcase and contaminated the oil.

Fuel rising high enough to enter the carb throat typically results from a leaking float valve (for whatever reason) and thereafter getting past the overflow circuit (where so equipped).

The proper float height is whatever produces the correct fuel level.

Good Fortune!

saxonpirate wrote: You don't say if the bike has been stood for sometime or the carbs rebuilt/cleaned...

If they are BS34's and you have pods fitted, remove the pod and push the slide up with your finger. Let go and the slide should return in one smooth movement. A mirror might help to see what's going on. As far as float height goes for the B34's, mine are 18.6mm +/- 1mm. This is for a KZ1100 ltd though, so check out the web for your bike. There may be a difference. Here's a link to a pdf by Ed Ness regarding the rebuild of Mikuni Carbs. Although it's aimed at Suzuki owners, it's very informative and features B34 CV carbs. Well worth downloading... COPY AND PASTE THE WHOLE LINK

www.mtsac.edu/~cliff/storage/gs/Mikuni_B...Rebuild_Tutorial.pdf

Re-jetting for exhaust and pods, the concensus of opinion seems to be an uprating of the main jet and "sometimes" the pilot jet, along with re-clipping the needle. I've actually gone the other way with my bike and returned to the stock air box and stock exhaust. Main 120 to stock 117.5 with stock pilot of 37.5 This is a subject which in my opinion requires a degree of experimentation with jetting and needle height, and there are many on this forum with far more practice than I have regarding uprating carbs, hopefully someone will come along...

That link is a good guide but one thing I find odd is the float height reference. My Kawi Service Manual says for my year 82 and up should be 18mm for BS34's whereas this guide says to use 22mm.

I don't recall my float or valve looking any different so why such a big variance?

My system is totally stock. How will changing my height to 22mm effect performance?

the higher the fuel level in the bowl , the easier it is for it to be drawn up the jets. (think, more pressure). so a higher level will make it run richer.

the dif in levels from 1 model to another would be related to the amount of vacuum the bike has available, to pull the fuel from the bowl. A bike with a smaller intake track, will have a higher vacuum signal..

mark1122 wrote: the higher the fuel level in the bowl , the easier it is for it to be drawn up the jets. (think, more pressure). so a higher level will make it run richer.

the dif in levels from 1 model to another would be related to the amount of vacuum the bike has available, to pull the fuel from the bowl. A bike with a smaller intake track, will have a higher vacuum signal..

Therein lies the problem with my understanding. If you can get past my shoddy paint graphic dumb this down for me.



If you are set at 22mm and change it to 18mm doesn't the level of fuel in the bowl get higher (closer to the jet) thus making it easier to pick up and run richer? Moving it from 18 to 22 would shut the flow off sooner, lowering the level and lean it out? So why recommend a measurement of 22mm?

that is correct. but its actualy further from the jet. the fuel must pass through the main jet, wich is lower in the bowl, near the bottom.

when u look at it like this :silly: its easier.