Why Do We Mikuni? or, Did I Drink The Koolaid too?

[Swagger]

The unfortunate truth is that I've yet to hear of a presented pair of carbs working right the first time out. There's just too many variables. Your bike is stock, right? Are you running stock pipes too? Even a pair of slip on mufflers will have a effect, then there's engine wear to consider. How hot is your ignition sparking.....and is it in time? Are your valves free and seating well? Are the adjusted correctly?

Heh.....nothing is simple, the toughest is often the most rewarding in the end though.....

 

[Rocan]

200 main is far too big....

heres ballpark figures I got (that I have yet to test) for jets that PJ helped me figure out....

176 P-2 Needle jet
4/042 #145 Main Jet
VM22/210 #25 Pilot Jet
BS30/97 #2.0 Air Bleed jet (if im not mistaken

these are figures for MY CB350 with VM30s, and I have a 1.5mm overbore which was calculated into these. either way, these will bring you closer then "pre-jetted"
really though, jetting carbs from scratch will probably leave you with 60 bucks of leftover jets.

 

[djelliott]

Hi. I recently fitted some pre-jetted Mikuni 30s on my cb350 from dimecitycyles (Jet size: 25 Pilot, 200 Main, 6F4 Needle, 2.0 Air Jet, P-5 needle) and switched to uniflow pods. I understood they were specifically 'pre-jetted' for cb350s with pod filters (stock everything else) - a simple switch - back on the road in no time.

I'm having trouble even getting the bike idling well (let alone actually rev without serious spluttering or cutting out) and have begun to wonder whether buying 'pre-jetted' carbs was worth it or whether I'm going to have to pay out more $ to embark on a long tunning process, which makes the whole notion of buying pre-jetted carbs kinda redundant...

Ah, hindsight...

Now, pass me that Koolaid.

Exact set up mine cam with, wicked stupid rich. I finally ended up down to a 150 and put in the proper bleed style emulsion tube and it still was never right IMHO. I'm having awesome luck with the stock CV carbs that I rebuilt. I might just stay with what seems to be working great.


Update on the SL Carbs. Got them, they were crazy filthy so I'm in the process of soaking and cleaning. Rebuild kits are on the way. They do indeed have a fascinating looking bore. I'll shoot some pics tonight and get the discussion rolling. The bore has a slight figure 8 look to it on the inside and opens up to 26 horizontal 27 vertical. Stand by for pics and measurements.


BTW, they look freaking hilarious sitting next to the VM30's on the bench.

 

[djelliott]

Aw crap, mission fail. One of the carbs is FUBAR. Totally pitted on the inside. Sucks I already ordered the kits. Hopefully I can sell them at mid ohio next week and get my dough back. Oh well, move along, nothing else to see here.