dan williams Posted May 8, 2017 Report Share Posted May 8, 2017 Ok that's a lot closer to correct though the travel is a bit less than optimum. Perhaps it's time to look elsewhere than the floats. Is your float bowl gasket in good shape? Quote Link to comment Share on other sites More sharing options...
betabell Posted May 8, 2017 Author Report Share Posted May 8, 2017 (edited) Hello Dan. I am glad I am getting closer to how it should be set up. Should I have more or less travel? I have put an new gasket on the float bowl but it did not make any difference. Should I buy some new floats? Edited May 8, 2017 by betabell Spelling Quote Link to comment Share on other sites More sharing options...
guy53 Posted May 8, 2017 Report Share Posted May 8, 2017 I'm no expert but, it almost seems like the gas is '' force '' out of the carb. Does it leak when the motor is not running ? Guy Quote Link to comment Share on other sites More sharing options...
betabell Posted May 8, 2017 Author Report Share Posted May 8, 2017 Hello Guy, no I have not noticed it leaking when the bike stands when not in use but I always have the fuel tap turned off. Quote Link to comment Share on other sites More sharing options...
lineaway Posted May 9, 2017 Report Share Posted May 9, 2017 Two things. you never spray carb cleaner in a bike carb.( I know every one does it) So look at the gasket of the needle and seat. It will swell three times the size with carb cleaner. Also you have never shown your vent hoses. ps I only use contact cleaner on my bikes. Quote Link to comment Share on other sites More sharing options...
betabell Posted May 9, 2017 Author Report Share Posted May 9, 2017 Hello lineaway I did not know that you should not use carb cleaner in a bike carb. Having said that the float needle, the needle itself the needle gasket and the float bowl gasket where not sprayed with carb cleaner because they where all new parts. It does make me wounded about the carb drain bolt gasket, that would have had carb cleaner on it so I shall replace it. I will photograph the vents when I get a min. Quote Link to comment Share on other sites More sharing options...
dan williams Posted May 10, 2017 Report Share Posted May 10, 2017 On 5/8/2017 at 1:17 PM, betabell said: Hello Dan. I am glad I am getting closer to how it should be set up. Should I have more or less travel? I have put an new gasket on the float bowl but it did not make any difference. Should I buy some new floats? No I think you checked your floats and they were good so not the floats. Your float level is pretty good now too. Only happening at 3/4 throttle is the odd thing that still points to vibration in my mind. Possibly a casting defect. This is a tricky one. I will give you credit for being persistent and patient with this. It's the hallmark of a good mechanic. Quote Link to comment Share on other sites More sharing options...
billyt Posted May 10, 2017 Report Share Posted May 10, 2017 The top arrow adjustment does not set the float travel but rather the needle seat travel. The floats do what they want to do independently from the perpendicular tang. If the floats go down hard from a drop off the small tang will always limit the needle travel. Quote Link to comment Share on other sites More sharing options...
feetupfun Posted May 10, 2017 Report Share Posted May 10, 2017 Is the (brass) overflow pipe secure in its hole in the bowl? If it can move in its hole from vibration, fuel can get to the overflow hose Quote Link to comment Share on other sites More sharing options...
feetupfun Posted May 10, 2017 Report Share Posted May 10, 2017 I've just looked at you photo of the float bowl and can't even see an overflow standpipe Quote Link to comment Share on other sites More sharing options...
dan williams Posted May 10, 2017 Report Share Posted May 10, 2017 10 hours ago, billyt said: The top arrow adjustment does not set the float travel but rather the needle seat travel. The floats do what they want to do independently from the perpendicular tang. If the floats go down hard from a drop off the small tang will always limit the needle travel. Fair enough. Wanted to keep it simple in practice. Quote Link to comment Share on other sites More sharing options...
dan williams Posted May 10, 2017 Report Share Posted May 10, 2017 I don't believe the Mikuni uses a stand pipe like the Keihin. If I remember correctly a bore in the float bowl lines up with a hole in the bottom of the carb body and there is an overflow hole into the top of the float chamber. Quote Link to comment Share on other sites More sharing options...
billyt Posted May 11, 2017 Report Share Posted May 11, 2017 Betabill In looking in more detail at your float bowl. Specifically the part where my pen is pointing to the marks/gouge is witness mark that at some point in time there was an issue with the pin that holds the brass tangs to the float carb body. This heavy gouge mark means that the pin was not in securely when the carb was placed back on the float bowl. After working with this carb for many many years I had seen one of these gouges before where it put a hair line crack in one of the posts and caused all sorts of flooding issues. The pin can and will float about from left to right however this is not on the side but rather a mark that has been forced into the top due to poor fitment. Can you get take a better more detailed picture of this area on the float bowl? Quote Link to comment Share on other sites More sharing options...
betabell Posted May 11, 2017 Author Report Share Posted May 11, 2017 Hello feetup my cab does not have an overflow standpipe. It is exactly as dan described, it is built into the castings of the carb body and float bowl. Interesting point billyt about the mark in the float bowl. I completely missed that, well spotted. The pin has always been in place when I have taken the carb apart many times, but as you say it there has clearly been some kind of problem in the past. I will take a better photo of this, it will probably be not for a couple of days. So I had some time yesterday so was messing around with the bike, I remember people mentioning about the floats catching on the gasket. So I had a look and noticed two things. Firstly the gasket did sick out one side a tiny amount we are talking 0.5-1mm. So I carefully trimmed this down but it made no difference. Secondly the casting of the carb where the gasket sits was not square. I will again take a picture of it. It may just be how they are all made, I don’t know? To describe where it is - there is a cut out where the gasket has a tab on that locates into the carb. It looks a bit like someone has hit it with a hammer. By that I mean that it is punched in a tiny bit, there are no signs of damage. As I say I will take a picture of it. The other thing I was thinking about that you guys mentioned is the whole vibration thing. Specifically about the carb hitting the exhaust. So I removed the silencer and the middle section and ran the bike but this did not make any difference. The fuel lines on the bike do touch the cylinder wall and a bit of the exhaust. I was wondering if they are a bit old and have gone hard could this be enough to disturbed the carb? I should say that I have ran the bike with one hand on the carb to see if that stabilizes it or if in some way that dampens the carb, but again it made no difference. I have a question about a flat piece of metal in the carb that the needle seat bolts through. What is its function and can I remove it. The reason I ask is that I have noticed that it does not sit squarely in the carb. I could take it out completely or I could try and file it down to make it sit squarely. Again I will take a photo of this. Thanks again for all the advice guys. Quote Link to comment Share on other sites More sharing options...
betabell Posted May 11, 2017 Author Report Share Posted May 11, 2017 This is not a new picture but show a couple of the things I mentioned. I will be taking better photos when I can tale the carb of in a couple of days time, Quote Link to comment Share on other sites More sharing options...
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