Witch Mikuni carb.shoud I get.

[GinoCasino]

I have a 1972 Six Day 125 cc. I am tried of messing with this bing carburetor. I want to put a Mikuni on it but im not sure what size or where to buy it? Any info would be helpful.

[Rick Bennett]

I will trade you a Mikuni for the Bing.
Rick 440-417-8094

[GinoCasino]

No Thanks ,I am trying to keep all the original parts I take off and pass them on to the new owner when I eventually sell.
Originally posted by Rick Bennett[/i]

I will trade you a Mikuni for the Bing.
Rick 440-417-8094

[Larry Perkins]

The Bing is a better carb. Most of the time when someone hates it it is because it is not set up right, they did not put in a NEW Needlejet, or slide is worn.  The Bing flows more gas in the same size carb as the Mikuni.  What is the Bing doing to give you trouble?

Larry P

[GinoCasino]

It starts and runs for 10 seconds then goes lean (Big Time) and quits. I did a total rebuild about 4 years ago including a carb cleaner soak. it was better but not right. Both the needle and seat were changed at that time. I didn't change the slide and will do that next. Also, does someone make block off plates to pressure check the engine for air leaks?

[firstturn]

Dont know  anyone who makes block  off plates, but easy to make.

Ron Carbaugh

[KJDonovan]

Gino,


Just get rubber pool plugs to do a leak down test.  They are available at any pool store or online.

Thanks,

Kevin

[Larry Perkins]

Also replace the needle jet with a new one.

Larry P

[gooddirt]

use clear  fuel line and check gas flow from petcocks...

[firstturn]

Have you  tried leaving the fuel cap off?


Ron Carbaugh

[Daniel P. McEntee]

quote:Originally posted by firstturn

Have you  tried leaving the fuel cap off?


Ron Carbaugh

    You don't know how many times I have come across this on motorcycles and lawn equipment like mowers and string trimmers. I had a guy where I work give me a like new Troy Built lawnmower because it would start, run for a few minutes and then die. Wait a bit and it would start right up and do the same thing again and again. He claimed to have taken it to several places and no one could figure it out. It did the same thing to me right off the bat. First thing I did was loosen the gas cap so the tank could breathe, and cut my entire front lawn with it. The cap is defective in some way, so I cut a groove across the flat where it seats against the tank so it can vent and all is well. I offered to give it back to him, no charge or anything, but he said he had just bought a new Honda mower and moved on! It is one fo those simple things that is easy to over look and forget about on a vintage bike much less something that is almost brand new. That is what bites you in the butt most often is the simple stuff. And that is what this issue sounds like to me also, the gas cap or the petcocks not flowing.
   Type at you later,
  Dan McEntee

[JP Morgen]

If you buy a Mikuni, I would suggest a 30mm because it shares parts and jets with the 30-34mm carbs, easier to find and more selection. Use a 6F5 needle, I may have other specs if you need. Good luck.

[Paul Danik]

Does the carb have a tickler on it? Does holding it down with both petcocks open allow fuel to run out of the carb when the bowl gets full, as it should ? If so, when you start the bike and it nears the point where it always starts to run lean, push down on the tickler and see if doing so makes a difference.

If it is a fuel flow problem be sure to pull the petcocks and make sure the screens inside the tank are not partially covered over with crud.

Is there plenty enough fuel in the tank to allow the petcocks to be in the normal open position and not in the reserve position as the lower portion of the screens inside the tank might be blocked.

If all else fails be sure to check the float setting.

Paul

[GinoCasino]

I would like to thank everyone for all of their help, support, and suggestions. I will definitely try them all until I get this mystery solved. It's great to get suggestions from experienced individuals that give me direction of where to go next. This is a great website to be able to learn from experiences from other members. I will keep everyone posted on what worked in my case.

[fischercycle]

hello out there i just pulled out my old 1968 400 husky to go to the vintage races this weekend at reynlow park , kicked it over a few times it almost took my right foot off, so i got my son to get it started it had the same problem running lean and up and down , so i took the mag, cover off and the bosch mag,off. just what i thought the mag seal hard as a rock replaced it runs like a old husky, so we are headed for the races,javascript:insertsmilie(':D') so check your engine seal the dry sidejavascript:insertsmilie('[]')ok, jake