kz1300 banner

Welcome, Guest
Username: Password: Remember me

TOPIC:

Another Carburetor Project. 4 months 2 weeks ago #30458

  • biltonjim
  • biltonjim's Avatar
  • Offline
  • Platinum Member
  • Platinum Member
  • Posts: 830
  • Thank you received: 206
Interesting, Bill. Looking forward to hearing about the outcome.

Please Log in or Create an account to join the conversation.

Another Carburetor Project. 4 months 2 weeks ago #30460

  • scotch
  • scotch's Avatar
  • Offline
  • Sustaining Member
  • Sustaining Member
  • Posts: 1817
  • Thank you received: 795
I am compelled make the following corrections:

"......and supposedly blocks off a passage that adds fuel....."
The Enrichment system does not ADD fuel.  It cuts off the supplemental mixing-air which in turn makes the fuel/air ratio, richer.

".........the fit between the plunger and the hole in the carb body is that it's way too loose....."
The diaphragm-piston to bore fit is not a high-tolerance fit.  It is intentionally loose to ensure freedom of movement.

".........was to plug up the holes in the carb throat that admit the fuel for this enrichment system. I know that others have chosen to defeat this system by interrupting the vacuum signal to the enrichment diaphragm but doing so does not address the loose fit I found between the plunger and the carb body.  I'm thinking that even when closed off that loose fit allows excess fuel into the carb throat......."
The enricher system does not deliver fuel.  From the vacuum port in the carb throat (1 per carb and on the left side of each - total of 3)  to the diaphragm, there is only vacuum.  On the piston side of the diaphragm there is only ambient /static air.   The piston starts to move (cut-off air) @ approx.. 10"Hg  and is closed at approx. 20"Hg.  When "closed" the piston does not fully cut-off this air.  The small screw in the end of the diaphragm cover is a piston travel limit adjustment dealt with at the factory to allow a predetermined amount of air to still pass into the fuel/air delivery galleries.
And yes, I know the "Manual" says this screw is to adjust the spring tension.  IT DOES NOT have anything to do with spring tension.  Consider the  # of coils,  wire gauge diameter and total unwound length and additionally  the .5? pitch and overall length of this screw and common sense should prevail, with this detail.

Hope this helps clarify






 


 
1980 KZ 1300 sr# KZT30A-009997
Always High - Know Fear !
The following user(s) said Thank You: PaulD

Please Log in or Create an account to join the conversation.

Another Carburetor Project. 4 months 2 weeks ago #30461

  • KZQ
  • KZQ's Avatar Topic Author
  • Offline
  • Administrator
  • Administrator
  • Lifelong Rider Suffering Through MBD
  • Posts: 1003
  • Thank you received: 250

I am compelled make the following corrections:

"......and supposedly blocks off a passage that adds fuel....."
The Enrichment system does not ADD fuel.  It cuts off the supplemental mixing-air which in turn makes the fuel/air ratio, richer.

".........the fit between the plunger and the hole in the carb body is that it's way too loose....."
The diaphragm-piston to bore fit is not a high-tolerance fit.  It is intentionally loose to ensure freedom of movement.

".........was to plug up the holes in the carb throat that admit the fuel for this enrichment system. I know that others have chosen to defeat this system by interrupting the vacuum signal to the enrichment diaphragm but doing so does not address the loose fit I found between the plunger and the carb body.  I'm thinking that even when closed off that loose fit allows excess fuel into the carb throat......."
The enricher system does not deliver fuel.  From the vacuum port in the carb throat (1 per carb and on the left side of each - total of 3)  to the diaphragm, there is only vacuum.  On the piston side of the diaphragm there is only ambient /static air.   The piston starts to move (cut-off air) @ approx.. 10"Hg  and is closed at approx. 20"Hg.  When "closed" the piston does not fully cut-off this air.  The small screw in the end of the diaphragm cover is a piston travel limit adjustment dealt with at the factory to allow a predetermined amount of air to still pass into the fuel/air delivery galleries.
And yes, I know the "Manual" says this screw is to adjust the spring tension.  IT DOES NOT have anything to do with spring tension.  Consider the  # of coils,  wire gauge diameter and total unwound length and additionally  the .5? pitch and overall length of this screw and common sense should prevail, with this detail.

Hope this helps clarify






 


 

 

Hi Scotch,
Thanks for those corrections. So if the deceleration enricher diaphragm does not move the air continues to flow. I guess I understand why the plunger fit is less important, when it's function is not to stop all flow.
In an earlier thread you described how you had defeated the enricher system. Would you please describe it once more?
Thanks
Bill
1947 Indian Chief, 1968 BSA Shooting Star, 1970 BSA 650 Lightning, 1974 Kawasaki W3, 1976 KZ900 A4, 1979 KZ750 B4, 1979 KZ750 B4 Trike, 1980 KZ550, 1981 KZ1300, 1982 KZ1100 Spectre, 1985 Kawasaki ZN1300, 1987 Yamaha Trail Way, 2000 Honda Valkyrie Tourer, 1981 GL 1100, 2009 Yamaha RoadLiner S

Please Log in or Create an account to join the conversation.

Another Carburetor Project. 4 months 2 weeks ago #30462

  • scotch
  • scotch's Avatar
  • Offline
  • Sustaining Member
  • Sustaining Member
  • Posts: 1817
  • Thank you received: 795
Simply remove the piston/diaphragm and spring - make a solid gasket (replaces the diaphragm) and seals the vacuum side of the cover.
1980 KZ 1300 sr# KZT30A-009997
Always High - Know Fear !

Please Log in or Create an account to join the conversation.

Another Carburetor Project. 4 months 2 weeks ago #30464

  • PaulD
  • PaulD's Avatar
  • Offline
  • Premium Member
  • Premium Member
  • Posts: 90
  • Thank you received: 18

Simply remove the piston/diaphragm and spring - make a solid gasket (replaces the diaphragm) and seals the vacuum side of the cover.

I’ve done this mod on my bike and it’s made no difference to the running BUT it has increased the MPG figure to 45mpg from 30mpg average 
well worth doing in my opinion 
 

Please Log in or Create an account to join the conversation.

Another Carburetor Project. 4 months 2 weeks ago #30465

  • scotch
  • scotch's Avatar
  • Offline
  • Sustaining Member
  • Sustaining Member
  • Posts: 1817
  • Thank you received: 795
thanks  Paul 

Although I won't dispute your claim about your increase in mileage I would suggest to others that  a 50% increase should not be anticipated or expected as typical.

It would be great  to hear from others who have done this simple mod. and after some diligent and consistent riding (At least 3 fills) could objectively report their results so a base-line could be established.  Doing this mod PLUS re-syncing, "Color Tuning, adjusting the ignition timing, bringing your tires up to the correct pressure, new plugs, etc., ALL at the same time would not be subjective and will merely mask the true result.

 
1980 KZ 1300 sr# KZT30A-009997
Always High - Know Fear !
The following user(s) said Thank You: PaulD

Please Log in or Create an account to join the conversation.

Time to create page: 0.070 seconds
Powered by Kunena Forum