Mikuni carbs

[Guy Wilson]

Off the bat, my question relates to running a Mikuni carb on Triumph TR6P and therefore is not BSA related...however, t is a general carb question, so forgive me for a moment, or imagine its running on a A10
I cannot get the engine to run without the choke on. Its running very lean. I'm at 6000ft about sea level and I have the needle at the highest position and the airscrew out at the maximum.  When I stop the engine, there's a lot of petrol vapor/mist that appears from the pilot intake at the base of the intake of the carb. The carb is super clean inside an out.  Would jetting down alleviate the need for the choke to be open or is there something else in play?
The last time I rode the bike on a long run, the engine locked up at speed. Would that suggest its not just the pilot/air screw setting?
I've no idea and may go back the erratic idle of the Amal...
Any thoughts?
thank you,
Guy

[Triton Thrasher]

Did it ever run right with this Mikuni?

[Guy Wilson]

I think it did, ALthough I mostly rode around town. I bought the Mikuni from Phil Ried originally,
It locked the engine up on a long run while riding hard. I'm assuming the carb was to blame.

[Guy Wilson]

you're probably right, I should throw the thing away and go back to the Amal

[Ted_Flash]

I have never swapped my Amals for Mikuni or any other type of carb.

However my wife always said that I'm Amal Retentive.

[muskrat]

If it only runs with the choke on it needs more fuel. Check the float height, might be low. A richer pilot will also richen the other jets.
At altitude it would need to be a bit leaner than at sea level but it might have gone too far.

" Amal Retentive" Ha, and also deef
Cheers

[chaterlea25]

HI Guy,

the airscrew out at the maximum

This is the leanest setting  which is NOT what you want !!!

You need to up the jetting, bigger main jet,  richer needle or needle jet, bigger pilot  ??????

Contact Sudco in California or Allens Performance in the UK
http://www.sudco.com/mikuni.html
http://www.allensperformance.com/

They will advise basic settings for your TR6

I find the Mikuni brilliant on my SR  and on several other bikes I have fitted them to

HTH
John

[duTch]

 My A10 had been running rich (389 Mono ), changed pilot & plugs-no change, but went down a size on the needle jet and made a huge difference so maybe look at that...?

[Scrambler]

This may be helpful information to compare you current jetting to.

http://www.braigasen.com/Mikuni_jetting_chart_four_stroke.htm

[Guy Wilson]

As always, thank you all.... I have plenty to go on.
Float level, needle height and jets,
BSA next weekend!
Guy

[Guy Wilson]

and air screw..