Questions on mikuni and wiring

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Are you guys getting sick of my questions yet? I hope not. Does anyone know of an on-line resource for rebuilding mikuni carbs? My bike has a sigle mikuni conversion on it, but the bike didn't come with any manuals/paperwork on the carb. The downstream side (the side that goes to the head) is 34mm in diameter, this is the right place to measure right? I can't find any model numbers on the carb, is there more than one model of 34mm mikuni used on commandos? It seems to be in very good shape but has sat for 4 years full of fuel from a unlined fiberglass tank so I am sure it needs a good cleaning. Here are some photos of the carb in case they help.

Questions on mikuni and wiring


Questions on mikuni and wiring


Questions on mikuni and wiring


Next question. My wiring looks as if someone rewired the the bike with random bits of salvaged wire or maybe adapted a harness from another bike. The bike supposedly ran fine before it was parked so in theory the wiring works, but is on the list of things to replace for sure. So here is the question, Why do I need a battery on a kick start bike? As long as I am going to be rewiring I would just as soon lose the weight.
Here are some shots of the wiring just for comic relief

Questions on mikuni and wiring


Questions on mikuni and wiring


Notice all the wires that are not connected to anything.

Questions on mikuni and wiring
 
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Jun 17, 2009
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A Boyer needs a battery kept charged.
An alternative to a battery is a, and I can't spell it but I fitted one, a "typatium" or something like that
 
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Looks like the orginal harness, the extra wires are for the Interpol model for the Police who had extra horns and other goodies.
 
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As far as rebuilding a Mikuni almost anyplace can do it. They are used on snowmobiles and various other equipment as well as bikes.
 

ML

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You have a Mikuni VN 34 carb. They are common and popular on Commandos. The typical jetting spec is shown here. You can also download a PDF file called Mikuni VM Carburetor Super Tuning Manual. Google that and you'll find it. Also, your wiring harness is shot. For about $150 you can get a new stock harness. My only advice is to flick the puny fuse terminals and fit some solid brass / copper types with strong solder.

SUITS 850 Commando VM34:

Main Jet 240

Needle Jet P2 or P4

Needle 6DH3 or 6DH4

Pilot Jet 30-35

Air Jet 1.0

Slide 3
 

Ron L

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Also, your wiring harness is shot. For about $150 you can get a new stock harness. My only advice is to flick the puny fuse terminals and fit some solid brass / copper types with strong solder.

I've seen a lot worse harnesses. I would hesitate to buy a new one. The added on wire was done for the re-located switch. If you buy a new harness you will need to add wire again to reach your switch. You won't be gaining much. The fuse holder needs to have a proper splice rather than the wire nut. The big multi-connector under the main tube looks bad. I would replace that with single bullet connectors.

If there is more splicing or relocated electrical parts the other alternative is to make your own harness using just the wires you need. Plenty of threads on how on this forum.

I would also not recommend running without a battery. You have the blue capacitor, but it is doubtful it works anymore. The stock alternators put out marginal power and the battery helps to feed a sufficient voltage at low rpm. A small AGM battery will save more aggravation than the weight you save by eliminating it.
 
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