Forum

[Enfield enthusiast]

Has anyone out there fitted a Mikuni VM30 to their bikes? I have a 2004 Bullet 65, had the inlet port taken out to 32mm and Hitchcocks 90052 competition valves fitted, and I am struggling to get the jetting set up correctly.
I currently have a 145 main jet in, having reduced this from a 190 as supplied by Allen's Performance, but still it is running rich, even with the air screw unscrewed as far as it will go. Any suggestions will be gratefully received.
Unfortunately, Mikuni, Mikarb, and Amal jet sizes do not co-relate, so no joy there.

[Gwilly]

Sounds like your way too rich on the pilot jet to start with, air screw should be no more than two turns out with the correct jet..

What sort of exhaust and air filter do you have on...

Have a look Here for some ideas courtesy of our friends across the pond..

[Enfield enthusiast]

Hi Gwilly, thanks for that info, I will have a good look at the website that you recommend, and once I get it sorted I will post you the settings that I finally use. I have a Hitchcocks free flowing exhaust 91007, and the air cleaner is a K & N RU-0600 High Flow Filter.

[ric]

Mikuni/Amal jet comparison chart

http://www.ozebook.com/compendium/t500_files/mikuni.pdf

[Enfield enthusiast]

Cheers ric, much appreciated.

[Creaky45]

It will be interesting to see how you get on as I have had the same problem. My 2006 Bullet is stock standard except for the 32mm Mikuni round slide carby I put on as I had problems with the Mikcarb. It came stock with a 200 main and 30 pilot but I was sold a jetting kit of 230,240 and 250 mains, a 35 pilot and another needle and needle jet. After hours of experimenting I nearly gave up. I had borrowed an oxygen sensor so I could see the mixture while riding and it was always too rich and ran badly. In the end I put the carby back to standard, (200 and 30 and original needle and needle jet) and, although it is running well it is still too rich on the oxygen sensor. I have even gone as low as 160 main and 25 pilot. (same pilot as Mikcarb uses) I no longer use the O2 sensor, just look at the plug which still shows a bit rich. Re the air screw, I can screw it right out and the motor still runs but when I screw it in it cuts out at one turn out which sounds ok. Maybe I need a leaner slide but with so many variables I have given it a miss for now. Runs good enough for me. If you want details of my needle and needle jet let me know. I've bored you enough for now.

[Enfield enthusiast]

On the contrary, I would be very interested to receive your settings. I have various main jets and a couple of pilot jets as supplied by Allens Performance, my problem with these pilot jets is that I cannot read what value these jets are, the markings are so small. Even tried a magnifying glass but no joy. Will be going back to the RE as soon as I have got my Jawa through the MOT!!

[Creaky45]

Your choice of a VM30 is a better one than my VM32 as my head has not been ported. I don't know what difference the competition valves would make. I'm not much into performance on this bike. I have a Triumph for that. I have a friend with a 2005 Bullet. It has a 34mm Mikuni, free flow muffler, 535 alloy barrel and high compression piston. It runs very well and the carby set up is as follows: Main 190, pilot 42.5, slide 2.5, needle jet 159Q2, needle 6DH2 and clip in middle slot. The plug always looks rich to me but he is happy with it. My Mikuni is as follows: Main 200, pilot 25, slide 3, needle jet Q6, needle 6DP17 and clip in second leanest slot. I only have the standard exhaust with the cat?? thingo removed from the engine pipe (muffler end). The bike revs out better and has more top speed but still feels a bit lumpy down low and I use more fuel than I did. It could no doubt be better tuned but there are so many combinations of jets etc. I think a dyno and endless time would be needed and I'm not getting any younger. Not sure if any of this helps but at least I can sympathize with you. My carby has been on and off so many times I only have to say, "Carby off" and next thing it's on the bench by itself.

[scotty]

Hi try t d hattrick townsville aust on www.mikunioz.com they have a free downloadable tuning manual, they are aust distributors for mikuni carbs, found it very helpful. Translator not required lol.

[Enfield enthusiast]

Thanks, Creaky 45 and scotty, I'm collating all the info that forum members have sent to me and hopefully I will finally get it set up right. Friends say they are brilliant carbs, but a swine to get set up correctly in the first place!! So, so true.