• Welcome to the forum website of the Vincent H.R.D. Owners Club.

    Should you have any questions relating to the Vincent H.R.D. Owners Club, or Vincent H.R.D. motorcycles in general, please contact Graham Smith, Online Forum Webmaster by calling 07977 001 025 or please CLICK HERE.

    You are unrecognised, and therefore, only have VERY restricted access to the many features of this forum website.

    If you have previously registered to use this forum website, you should log in now. CLICK HERE.

    If you have never registered to use this forum website before, please CLICK HERE.

Mikuni pilot


Well Known and Active Forum Website User
VOC Member
:( OK I am stumped!
As an old Amal hand this is my first Mikuni (28mm VM) set up by Alens. It is a great improvement, my cooking Comet has never gone so well.
I can tell however that its too rich on the pilot and I understand that the pilot screw gives some adjustment but for my 8 stroking beast I have bought some smaller pilot jets 1 and two sizes down to fit (minute brass items with a small slot in end)

Thing is I have the drawing (pilot is 21 in diagram) and here is a blurred picture of the underside but for the life of me I cannot see where the pilot fits! The two obvious holes are drain pathways to the drain pipes. nowhere do I see the end of the pilot jet and the whole thing seems far to delicate to go scraping around with a electricians screwdriver

I f you know where it goes please let me know refer to a clock on the blurred picture with main jet in centre (ie my thumb is at 1/4 to nine)

Comet Rider

Well Known and Active Forum Website User
VOC Member
Pilot jet goes in the hole at 9 o'clock to the main jet as per your pic'
The mixture screw is only an air bleed for the fixed pilot jet.
When I get home I'll send you a pdf document



Well Known and Active Forum Website User
VOC Member
Found it!
replaced the pilot jet with a 25 other option is a 27.5 (I cant see what was in there I don't have a scanning electron microscope in my garage to read it :))
Out on test its much better (without any adjustment with the air bleed) its ridable now but I get an impression that the richness extends past the pilots range OK when pulling hard but 8 strokes if off load I will have to read up on what controls the next opening and mark up my twist grip to see where it actually occurs (i have never known such a light throttle -wonderful) thanks Neil
Warning! This thread is more than 8yrs ago old.
It's likely that no further discussion is required, in which case we recommend starting a new thread. If however you feel your response is required you can still do so.