Mikuni again

MrNorton · May 10, 2010

Hi fellows,i have still problem with my VM36 Mikuni:needle 6DH4 and main jet between 225-280 does not work.
Maybe that needle is wrong.I tryed bigger main jet(350)needle was lowest position and every time when i opened throtle engine was "shooting"-mixture was too leak.Next time i will take so thin needle as possible and checking how it works.

Good pages:http://www.cyclewareables.com/pages/mikuni_vm_jet_needles/mikunivmjetneedles.htm

pete.v · May 10, 2010

I have a 750 with Combat head, BigBore exhaust and 36mm VM. Although I have gone to a Flatside TM, it ran great with a 6DH3 needle, a #159 Series Q2 needle jet, 300 main and the clip in the middle. I would think my configuration, with the head and pipes, should be fairly close to your needs, possibly going a little smaller on the main(280).

pelican · May 10, 2010

you using stock throttle with that 36mm?

pete.v · May 10, 2010

pelican said:
you using stock throttle with that 36mm?

I am. No issues what so ever. It does, however, require 45 bend at the carb top for clearance. Do you concur, MrNorton?

twinshocker · May 10, 2010

I have another carb question.

I am planning to replace my Amals , so which is the way to go ?
Two Mikunis, one single Mikuni ? Flatslide, Roundslide ?
I have a brandnew 38mm Dellorto from a Husky Fourstroke liying around has someone tried one of these ?
I know that this was discussed before but what are your opinions ?

Commando75 · May 10, 2010

What are you running for your ignition? It was my experience that until I stepped up to a Trispark, I needed to mess with the carbs more than I wanted to. After Trispark installation, setting up my Amals was a breeze. Near perfect idle etc. My Amals are new manufacture. So, before deciding to convert to Mikuni I would consider buying a new set of Amals or having yours rebuilt. I also cannot say enough about Trispark. I was running a Boyer prior to the Trispark and the difference is huge. Good luck!

twinshocker · May 10, 2010

Commando75 said:
What are you running for your ignition? ......

I have the bike since 4 weeks and am new to commandos. I have dismantled everything fo a rebuild.
All i see is that it says "SPARX" on the ignition plate ? Is that a good one ? :roll:

MrNorton · May 10, 2010

I bought that throttle(cabel)from Old Britts some years ago,if you mean that.I don´t know what is wrong but that concept:needle 6DH3/6DH4 and main jets between 225-280 does not working.
The best result was main jet 225 and needle 6DH4,second clip from top,but still fourth gear and after 5000 rpm engine lost power.If you look that Mikuni web pages,these 6DH3 and four needles are quite thick...

jseng1 · May 11, 2010

The best carb and the best deal by far is a pair of Keihin/PWK 32mm flat slides.

They are available tuned specifically for Norton twins by yours truly for only $150 each. Thats unbeatable and they work perfectly - already setup for Commandos.

contact

Jim@jsengineering.net

Photo below is a set installed on a cafe featherbed. Additional options include curved intake manifolds and cone shaped K&N style aircleaners for Commandos.