Re: Max Performance - Yamaha QT50/SG50

Dirty30 Dillon /
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The biggest problem with running a large carb on small cylinder (especially on an single speed, fixed ratio transmission) is that you're really never going to get AS accurate tuning as you could with a smaller, proportionate bore, because your intake pulse/draw is weakened. Generally speaking, in flow dynamics you lose fluid speed velocity the greater your volume is. Big bore carb means air travels through it slower and has a slower reaction to throttle input changes because of this. In addition, many modern carbs are HEAVILY reliant on a strong intake pulse to properly meter

This is really true of mikuni carbs, where EVERY VM20 bike I have ever built or worked on whether for friends or Second Stroke/NYC Mopeds build, ran decently with the factory jets the VM20 comes with.

Now, I can tune it in from there, but their pulse metering is so good, they typically just work, unlike a PHBG.

Again, this can be motivated through many ways to get decent results, but in the end I will typically err to smaller carb per build.

This single post is part of a larger thread. Start from the top or view this post in context.
Subject Written By Posted
  Max Performance - Yamaha QT50/SG50Topic by: Christoffer Janner Christoffer Janner 05/03/22 04:55AM
  Re: Max Performance - Yamaha QT50/SG50Re: Dirty30 Dillon Dirty30 Dillon 05/03/22 06:01AM
  Re: Max Performance - Yamaha QT50/SG50Re: Peter v. Peter v. 05/03/22 07:36AM
  Re: Max Performance - Yamaha QT50/SG50Re: Stephen Keller Stephen Keller 05/06/22 10:16PM
  Re: Max Performance - Yamaha QT50/SG50Re: Peter v. Peter v. 05/07/22 05:44AM
  Re: Max Performance - Yamaha QT50/SG50Re: Full Tuck Full Tuck 05/03/22 07:41AM
  Re: Max Performance - Yamaha QT50/SG50Re: Graham Motzing Graham Motzing 05/03/22 01:56PM
  Re: Max Performance - Yamaha QT50/SG50Re: Dirty30 Dillon Dirty30 Dillon 05/03/22 04:43PM
  Re: Max Performance - Yamaha QT50/SG50Re: Jack Rutherford Jack Rutherford 05/03/22 02:33PM
  Re: Max Performance - Yamaha QT50/SG50Re: Jack Rutherford Jack Rutherford 05/03/22 02:40PM
  Re: Max Performance - Yamaha QT50/SG50Re: Keegan Wilhelm Keegan Wilhelm 05/03/22 02:51PM
  Re: Max Performance - Yamaha QT50/SG50Re: Jack Rutherford Jack Rutherford 05/03/22 03:23PM
  Re: Max Performance - Yamaha QT50/SG50Re: Peter v. Peter v. 05/03/22 05:04PM
  Re: Max Performance - Yamaha QT50/SG50Re: Dirty30 Dillon Dirty30 Dillon 05/03/22 06:04PM
  Re: Max Performance - Yamaha QT50/SG50Re: Peter v. Peter v. 05/04/22 09:29AM
  Re: Max Performance - Yamaha QT50/SG50Re: Dirty30 Dillon Dirty30 Dillon 05/04/22 01:12PM
  Re: Max Performance - Yamaha QT50/SG50Re: Isaiah Rolon Isaiah Rolon 05/10/22 02:47AM

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