When the Mikuni leaks, it's usually due to a float level which is out of adjustment. When the float levers are not set at the proper level (24/32" to 21/32"), too much gas can flow into the carburetor bowl. thepiniongear shows here how to check the height of the float levers. That's the title of the video. It's not easy to segment videos into detailed instruction and still give a comprehensive solution. This isn't a repair video -- that's another segment to the whole. Lighten up. I benefited from this video and I thank thepiniongear for posting it.
My manual tries and tell me to make each tang on the arm parallel to the bowl, vs trying to measure. It is a VM34 in my instance.. but the larger VM on my old Yamaha is set the same and she purrs... I hope the floats are all the same as previous person swapped floats from a VM36 into mine.. old ones not with rest of carb so must have been soaking gas.. I see they make round and oval cut-aways for VM series.. hope they have same settings..
if you know the height of the gasket lip you can simply measure the height and subtract the thousandth of an inch without the razor blade routine. Besides, if your ruler is in 32nds then measuring to thousandths accurately is not going to work. Or did I miss something...I have never worked on carbs but am trying to learn.
Sorry, but float valves don't leak because the float level is slightly out! Think about it. They leak because they are worn or there is dirt on the needle / seat which stops the valve sealing. The reason we set float heights (or fuel level) is to provide the fuel at the correct height in the needle jet for the intake suction to pull it through in the correct ratio, If the fuel level is too low, it will make the engine run lean, if it's too high it will run rich. Leaking valves have nothing to do with small adjustments to float heights or fuel levels! I rebuild Mikunis all day 5 days a week! Get yourself a short length of flat steel bar 3mm thick, lay it across the gasket face and use a vernier to measure up to the float arm (half way along) The measurement for the VM38 is 17mm - 19mm so deduct 3mm (thickness of the steel bar) and your vernier should read 15mm when the float arm is adjusted correctly. Simple!
+Steve Motocarb How the hell do you rebuild them 5 days a week? They don't even make rebuild kits for them anymore as far as I can tell....Been looking for two days for a rebuild kit for some VM-40's for a 97 Formula Z and as far as I can tell it is a paperweight.
And when you set them up, are the float arms parallel to gasket surface after you use measurement method? I have this repair manual claiming all VM are set that way, my IT250 and 400 ended up parallel or dang close to after measurement method,, so hadn't any reason to question that method.. sure would make things easier..
I would of just layed the knife blade down and then just subtracted the thickness of the blade off the measurement , ur way u gotta hold the ruler at the bottom of the blade which is a pain in the ass.
i have been looking all over for this info on this carb with dog leg float lever. Thanks very much.
arnold ososki same
When the Mikuni leaks, it's usually due to a float level which is out of adjustment. When the float levers are not set at the proper level (24/32" to 21/32"), too much gas can flow into the carburetor bowl. thepiniongear shows here how to check the height of the float levers. That's the title of the video. It's not easy to segment videos into detailed instruction and still give a comprehensive solution. This isn't a repair video -- that's another segment to the whole. Lighten up. I benefited from this video and I thank thepiniongear for posting it.
Thanks for the Great Video & your time . Very helpful
great detail and common sense tips. It's helped me. thanks for posting.
thanks for posting.
My manual tries and tell me to make each tang on the arm parallel to the bowl, vs trying to measure. It is a VM34 in my instance.. but the larger VM on my old Yamaha is set the same and she purrs... I hope the floats are all the same as previous person swapped floats from a VM36 into mine.. old ones not with rest of carb so must have been soaking gas.. I see they make round and oval cut-aways for VM series.. hope they have same settings..
if you know the height of the gasket lip you can simply measure the height and subtract the thousandth of an inch without the razor blade routine. Besides, if your ruler is in 32nds then measuring to thousandths accurately is not going to work. Or did I miss something...I have never worked on carbs but am trying to learn.
I just wondering what bike are you putting that VM 38 on.
Sorry, but float valves don't leak because the float level is slightly out! Think about it.
They leak because they are worn or there is dirt on the needle / seat which stops the valve sealing. The reason we set float heights (or fuel level) is to provide the fuel at the correct height in the needle jet for the intake suction to pull it through in the correct ratio,
If the fuel level is too low, it will make the engine run lean, if it's too high it will run rich.
Leaking valves have nothing to do with small adjustments to float heights or fuel levels!
I rebuild Mikunis all day 5 days a week!
Get yourself a short length of flat steel bar 3mm thick, lay it across the gasket face and use a vernier to measure up to the float arm (half way along) The measurement for the VM38 is 17mm - 19mm so deduct 3mm (thickness of the steel bar) and your vernier should read 15mm when the float arm is adjusted correctly. Simple!
+Steve Motocarb How the hell do you rebuild them 5 days a week? They don't even make rebuild kits for them anymore as far as I can tell....Been looking for two days for a rebuild kit for some VM-40's for a 97 Formula Z and as far as I can tell it is a paperweight.
Steve motocarb i have a question on th tm 36mm mikuni carb flost levels?
And when you set them up, are the float arms parallel to gasket surface after you use measurement method? I have this repair manual claiming all VM are set that way, my IT250 and 400 ended up parallel or dang close to after measurement method,, so hadn't any reason to question that method.. sure would make things easier..
this sucks with hover strength. its great your float doesnt leak what a waste of 8 mins for those of us with a float problem
I would of just layed the knife blade down and then just subtracted the thickness of the blade off the measurement , ur way u gotta hold the ruler at the bottom of the blade which is a pain in the ass.