mikuni carb By bcgreatness (Read 764 times)

[bcgreatness]

IeDon't know where to post this but anyway, my buddy over heard me talking about my carb's diaphram needle almost breaking so while he was at work today at the local junk/ salvage yard, they had an old scooter that was about to be crushed so he managed to snatch the carb from it before it was scrapped. He does not know anything about scoots so he wasn't sure if it would work on my scoot or not. Was pretty cool of him to do that.i can already tell that it won't work because the carb is awfully big. I can't find any numbers on it to look it up and so far I've searched for a couple of hours trying to atleast find a pic of it so i can see what type of bike it goes too but for some reason i can't find it any where. All i need to do is find out if the diaphram needle from the mikuni will fit in my stock case carb. I believe that it was for a250 scoot due to it looking like it has a spot for a coolant hose i know, you want me to Take pictures so that way you know what I'm talking about i will do so later on in the day. Another thing is the auto enricher is located at the very bottom of the carb.

[Bashan]

Sorry, it won't fit. Mikunis are specific unto themselves and none of the parts are interchangeable with other carbs. That was pretty cool of your friend to do that. Rich

[bcgreatness]

Darn oh well. Maybe somebody else can get more use out of it then me. I know it can be used on my scoot if it were just a little shorter. I might take some measurements and see if i can't cram it in there lol. I guess I'm going to get to cleaning it out.

[jct842]

A 250 carb on a 150 WIL run like sh!t. Too much air, it will not have any or little vacuum to run your fuel pump. Many many threads here and other forums about TRYING to get a larger carb working properly. It can be done but must include opening up the exhaust, re-jetting, cam, big bore, etc. Best fix is replace carb with same or there are some parts available including needle and diaphragm from some of the parts houses. A new needle could be made on a lathe but if your time is worth more than 50 cents an hour is best to buy it. I have a lathe and milling machine in my shop and would still buy the parts.

[Bashan]

Great point about the vacuum John. Also, the vacuum has to pull a certain amount of fuel out of the jet and work the vacuum slide. They sell a lot of bigger carbs that are made for 150s and they still make them run like crap. It's a racket if you ask me. Rich

[sprocket]

We used to turn custom needles with different profiles...you can get some pretty funky throttle responses... TAIG Tools..micro lathes...

www.leevalley.com/en/wood/page.aspx?p=43104&cat=1,330,50260&ap=1

also
www.sherline.com/

[bcgreatness]

[bcgreatness]

would have to study this carb to see what goes where because nothing is marked at all, most of it should be common sense though just a quick note, i measured the size of the intake port and the intake manifold port, the intake manifold on my bike will fit on it and my intake tube will fit on it as well. also my carb that i have on it now, the petcock works off of the intake manifold. too bad this carb wont fit in my scoot without major modifications there is a peice of frame that it hits, thats the only thing preventing it from fitting, also i would have to change the plug for the enricher so that it would plug into my bike, or i could do a bypass on this one if its possible.

[bcgreatness]

went on a ride earlier today, made it almost home and the pin finally broke in half, had to push my scoot the rest of the way home. took the needle from the mikuni carb and measured it out. compared measurements to the stock needle, and its a match! i switched out the needles and she runs better then the other needle had it running ( before the needle started to break ) still trying to find out any info about this carb so that way i can either hook it up or sell it, maybe trade it. while it was apart, i took notice that its a very very well built carb and its very clean on the inside.