• 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.

Setting up shadow carbs

Rob H

Well Known and Active Forum Website User
VOC Member
Bike does not seem to pull on full throttle and wondered if the main jet was too small (currently running 180's and 3.1/2 slides and K&N filters) seems to run better when backing it off.

What size mains are members using these days with the 1.1/8" carbs on modern fuel?

Would also like to try and set up the bike on a rolling road / dyno to make sure the carburation is spot on throughout the range.

can anyone recommend who to do to?


Vincent Brake

Well Known and Active Forum Website User
VOC Member
its to rich on the end when if a little less throttle runs better, so a smaller yet is better, the plug might see black also


Well Known and Active Forum Website User
VOC Member
I am using 170 main jets, 34º advance (new BT-H), K&N filters and a fairly quiet silencer. 7.3:1 compression and 3 1/2 slides. At times I think it
is a tiny bit rich but overall performance is excellent so leave well enough alone. When I did the recent strip down there was a little bit of
carbon at the top of the bore but hone marks were still visible and valves were good. Probably only 15-20,000 miles though since a major
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.