MossyRock125 Posted October 13, 2018 Report Share Posted October 13, 2018 Hello everyone, I have significant carb issues on my Beta Rev-3 at the moment, the problem started a few days ago when i went to start my bike and noticed petrol dripping from the bike from the overflow pipe, this is fairly normal before it is started as most rev-3s do this before the engine is running. However once the bike had started, I took another look at the overflow pipe and petrol was still running like a river. I waited a minute or two to see if it stopped and it didn't. So i took off the car and bent the brass tab that controls the fuel inlet valve so the valve would shut off the flow off the fuel before it overflows the carb. I then put the carb back on and the problem persists. I have looked through millions of guide by others on this forum and just want a straight forward answer to fix it because it means i can't run the bike. All help, advice and answers are greatly appreciated. Thanks, James. Quote Link to comment Share on other sites More sharing options...
heffergm Posted October 13, 2018 Report Share Posted October 13, 2018 Sounds typical of a stuck float. Quote Link to comment Share on other sites More sharing options...
oni nou Posted October 13, 2018 Report Share Posted October 13, 2018 (edited) 1 hour ago, MossyRock125 said: Hello everyone, I have significant carb issues on my Beta Rev-3 at the moment, the problem started a few days ago when i went to start my bike and noticed petrol dripping from the bike from the overflow pipe, this is fairly normal before it is started as most rev-3s do this before the engine is running. However once the bike had started, I took another look at the overflow pipe and petrol was still running like a river. I waited a minute or two to see if it stopped and it didn't. So i took off the car and bent the brass tab that controls the fuel inlet valve so the valve would shut off the flow off the fuel before it overflows the carb. I then put the carb back on and the problem persists. I have looked through millions of guide by others on this forum and just want a straight forward answer to fix it because it means i can't run the bike. All help, advice and answers are greatly appreciated. Thanks, James. What you are asking of people is impossible as they cannot see your carburettor so that they can come up with a definitive answer on how to fix your problem ...bending the brass tab was not the thing to do really.What you need to do is make sure the floats float in petrol,and that the float valve tip is in good condition and there is no dirt between it and where it seats.If it worked ok before then there is a simple problem that lies in the fuel shut off valve parts of the carb.....Floats, Float arm and pivot pin and the fuel shut off valve that consists of two parts and the important float height .that completes the operation Edited October 13, 2018 by oni nou 2 Quote Link to comment Share on other sites More sharing options...
MossyRock125 Posted October 13, 2018 Author Report Share Posted October 13, 2018 Thanks for the comments. Sorry I hadn't posted any pictures, the floats have been checked and they do go up as they should. The valve needle looks nice and clean however it hasn't been taken apart so that's something I will check. Should have mentioned that at the start. There is also marking on the brass pin from where the floats have been pushing the brass pin. Quote Link to comment Share on other sites More sharing options...
island rich Posted October 13, 2018 Report Share Posted October 13, 2018 (edited) Hi Check out the Billy T how to set up your rev3 carb. Brilliant ... do the breather pipe conversion and do the set up on the float levels and you will have a sweet running engine and No petrol leaking . I used to drain my carb after every trial and didn’t have any problems with it as it’s a pain to take the carb off a rev 3 compaired to the evo’s . Edited October 13, 2018 by island rich Quote Link to comment Share on other sites More sharing options...
billyt Posted October 13, 2018 Report Share Posted October 13, 2018 Hi Mossyrock. As Island Rich says check out my post from many years ago on this issue. This adjustment works as several can attest too. I agree with Oni nou in that you should not be ramdomly bending tabs if you don't understand all the functions of the brass tabs. Check out my Mikuni article pinned on this site somewhere. Good luck BillyT Quote Link to comment Share on other sites More sharing options...
lineaway Posted October 14, 2018 Report Share Posted October 14, 2018 http://trialsport.com.au/beta/Manuals/mikuni/ 1 Quote Link to comment Share on other sites More sharing options...
lineaway Posted October 14, 2018 Report Share Posted October 14, 2018 This section that Billy T. Wrote saved me at the UTE CUP this year. I have read this dozens of times. My Keihin had stuck the floats which caused me to run out of fuel. I needed a real fix to not happen again. I could not believe I remembered this while in a panic not to DNF. `We will now set the little tab that sticks out perpendicular on the brass tangs. The purpose of this tab is to stop the actual travel of the tangs downwards. This is important, as it will alleviate many anomalies once set correctly. One must know that the small pointed plunger that the brass tangs pushes up acts like a light switch. The gas is either on or off. With this in mind one need only have this plunger move enough to allow the gas to flow freely and then close when the tangs act upon it pushing up. Think of this! When you land off a large rock the weight of the floats push quite rapidly down inside the float bowl. This is known as gravity. The extended movement of the floats downwards tends to do two things. It moves the floats way down inside the float bowl allowing more gas than needed and it also causes some of the excess gas to be pushed up into the jets and into the engine. It also if not set correctly allows the float tangs to travel down to far. It is kind of like being inside a fast moving elevator and when it reaches this bottom it kind of makes you bend your knees. In other words the elevator has stopped but you are still going downwards. So how do you set this travel tab? Adjusting the travel tab on the carb will not stop the floats from going down but it will stop the float level tangs from travelling all the way down. This is important as the further they travel the more they are likely to stick.` Thanks Billy! Quote Link to comment Share on other sites More sharing options...
billyt Posted October 14, 2018 Report Share Posted October 14, 2018 Glad to be of help Bob. When you coming through to ride with us in AZ? Quote Link to comment Share on other sites More sharing options...
MossyRock125 Posted October 14, 2018 Author Report Share Posted October 14, 2018 Great. Thanks for the guide, I'll have a crack at it today. Quote Link to comment Share on other sites More sharing options...
lineaway Posted October 14, 2018 Report Share Posted October 14, 2018 Maybe December at Oak Flat`s if I can talk my son into it. Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.