Author Topic: BS200 jetting etc.  (Read 2220 times)

0 Members and 1 Guest are viewing this topic.

Offline BRT-GTR

  • Brian
  • Trade Count: (0)
  • Master Registered Bridgestone Member
  • *****
  • Posts: 566
Re: BS200 jetting etc.
« Reply #20 on: January 21, 2017, 11:05:36 AM »
        Got to ask ---- Did Mikuni use a revised numbering system on the later carbs  for mains, pilots, needles etc.

  Also found these on the UK Mikuni site  -  UFO inserts.  Not available for 26mm carbs  (yet?) but look pretty simple.  Just smooths out the bottom of the carb slide and  cuts turbulence with significant performance benefits ?????    Might interest Rod (Husker) and others including me  ;).

    http://www.motocarb.com/ufo-insert.html                                                          Brian.
« Last Edit: January 21, 2017, 02:07:32 PM by BRT-GTR »
Growing old is compulsory, Growing up is optional.

Offline OldSwartout

  • Global Moderator
  • Trade Count: (0)
  • *******
  • Posts: 936
Re: BS200 jetting etc.
« Reply #21 on: January 21, 2017, 08:29:24 PM »
       UFO inserts.  Not available for 26mm carbs  (yet?) but look pretty simple.  Just smooths out the bottom of the carb slide and  cuts turbulence with significant performance benefits ?????    Might interest Rod (Husker) and others including me  ;).
Don't do it! They completely screw up the whole jetting system.  It can be fixed with different main jet, idle jet, needle jet, and needle.  Just count on many hours of trial and error to get the job done.

It's really not quite that bad, but it will take a few new parts and quite a bit of time to get it right.

My brother put those in his CB350 just before Daytona one year, bad mistake.
Karl Swartout
Mooresville, IN
BS175 Roadracer
BS350 GTR

Offline BRT-GTR

  • Brian
  • Trade Count: (0)
  • Master Registered Bridgestone Member
  • *****
  • Posts: 566
Re: BS200 jetting etc.
« Reply #22 on: January 22, 2017, 09:29:58 AM »
     Thanks Karl, the message is clear.  Did your brother ever sort the CB ?

  Even so, as a gas flow engineer, I can see the logic. Could effectively simulate the fitting of a bigger carb !! with increased air and fuel flow, at very little expense and no engine modification. Maybe when I've got a spare GTR running and time to play, I'll give it a try. Our buried carbs won't help.                  Brian
Growing old is compulsory, Growing up is optional.

Offline OldSwartout

  • Global Moderator
  • Trade Count: (0)
  • *******
  • Posts: 936
Re: BS200 jetting etc.
« Reply #23 on: January 22, 2017, 10:41:55 AM »
He did get it mostly sorted after another race weekend or so and they may have helped a bit. He never had dyno data. He had a very aggressive camshaft that caused some valve spring problems which didn't help matters any. Trying to jet the bike with broken valve springs didn't work well.  He did have the fastest CB350 in AHRMA for a while.

The UFO inserts do sound like a good idea. The smoother flow across the needle and jet seemed to change the jetting characteristics significantly, and not proportionally across the full range, so everything had to change.  The idle and low to mid opening curves apparently change quite a bit.  Trying to get idle, low throttle and roll-on correct was the biggest problem.  They've been around long enough that there may be more data on what specific changes should be used to start with.  He was trying them in 2002/2003?, not long after they came out.
Karl Swartout
Mooresville, IN
BS175 Roadracer
BS350 GTR

Offline BRT-GTR

  • Brian
  • Trade Count: (0)
  • Master Registered Bridgestone Member
  • *****
  • Posts: 566
Re: BS200 jetting etc.
« Reply #24 on: January 23, 2017, 08:35:24 AM »
           2003?  Didn't come across them until now, maybe not quite the 'magic bullet' they had hoped for. Bit like the Wal Phillips fuel injector from the 60's but worth further consideration.                                  Brian.
Growing old is compulsory, Growing up is optional.

Offline OldSwartout

  • Global Moderator
  • Trade Count: (0)
  • *******
  • Posts: 936
Re: BS200 jetting etc.
« Reply #25 on: January 23, 2017, 08:48:24 AM »
Speaking of fuel injection, I think someone that has a decent understanding of the electronics involved could adapt a couple of the units from modern dirt bikes to an old 60's/70's bike.  The dirt bike ones don't need much power, some even work just from kickstarter speed generating enough electrical power for initial startup, so they don't need a battery.
Karl Swartout
Mooresville, IN
BS175 Roadracer
BS350 GTR

 


Gallery


Views:36
Comments (0)
By: busagsx1300

Views:27
Comments (0)
By: busagsx1300

Views:59
Comments (0)
By: AlanJohn

Views:66
Comments (0)
By: AlanJohn

Classifieds

License Plate Frame

Date: 07/18/2017 06:13 pm
Time Left: 83d 16h 35m
175/200 Gas Tank

Price: $0.00
Date: 07/13/2017 03:28 pm
Time Left: 78d 13h 50m
Seat

Price: $0.00
Date: 07/13/2017 03:24 pm
Time Left: 78d 13h 46m
Rockford 2 Cycle Oil

Price: $0.00
Date: 06/14/2017 04:29 pm
Time Left: 49d 14h 52m

Recent Downloads added

How to build a 149 mph 350GTR....
Rating: (None)
Downloads: 29
Filesize: 7154.56KB
Date: April 18, 2017, 07:25:38 AM
Comments (0)
Bridgestone 100 Sport Brochure
Rating: *****
Downloads: 55
Filesize: 937.72KB
Date: July 08, 2015, 11:58:53 AM
Comments (1)
BS 100 Sport Australian Brochure
Rating: *****
Downloads: 39
Filesize: 937.53KB
Date: June 29, 2015, 05:40:40 PM
Comments (0)
Bridgestone 350 GTO - Moto L├ęgende May 2003
Rating: *****
Downloads: 85
Filesize: 9429.41KB
Date: April 22, 2015, 03:18:43 PM
Comments (0)

Powered by EzPortal