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Re: Single carb on Mastiff AGAIN!

PostPosted: Tue May 26, 2020 11:58 am
by AIRMANBEAR
THANKS FOR THE TIP.... YOU MUST BE FROM CORNWALL OR DEVON... WHERE MY FAMILYS FROM IN 1620s..... IVE RIDDEN THERE OFF ROAD ..
I HATE THOSE 2 CARB SET UPS AND MINE AND G STARTED STICKING THE THROTTLE PLATE … AND HAD TO BUY ANOTHER SET WISH I AHD SEEN THIS ARTICLE FIRST .. TO WIND UP WITH ONE CARB … NOW IM HAVING TROUBLE WITH LOOSING SPARK OVER 2500 RPMS...……….? A MYSTERY SO FAR...on my SCORPION.. 1996…...ANY SUGGESTIONS..???
ED N.Y. USA …...

Re: Single carb on Mastiff AGAIN!

PostPosted: Wed May 27, 2020 6:11 pm
by breakwellmz
As good as it performs, I feel i must be missing out on upper rpm power by so crudely reducing inlet breathing as well as reducing total carb area. The airbox is now much more `open` as well.
I`m thinking of possibly re-utilising the blanked-off  LH head port adding a small (24-26mm) CV carb., actuated  only by vacuum from the left hand port.  (a slave carb?)
No butterfly, cable, choke and maybe even a blocked off idle system (the starting, idle and low to mid speed response are really good with the pumper CV carb.
Any thoughts most welcome.

Re: Single carb on Mastiff AGAIN!

PostPosted: Thu May 28, 2020 12:49 am
by DAVID THOMPSON
we are all EARS keep us informed
Dave

not looking for big hp just some thing that runs NICE :smt023

wife keeps saying "sidecar" every time i go to work on any of the bikes

Re: Single carb on Mastiff AGAIN!

PostPosted: Sun Jul 26, 2020 5:44 am
by breakwellmz
Well here is the latest version.
Link port within head joining the two inlet ports has been blanked off so LH valve supplied only by what can be dragged through the 14mm ID copper pipe.
The engine feels freer(?) to rev without loss of bottom end, instant starting and solid idle, less banging on the over-run is a bonus.

Re: Single carb on Mastiff AGAIN!

PostPosted: Mon Jul 27, 2020 3:57 am
by Puffs
Following a biased and flawed moderator choice (someone posting aggressive personal attacks is rewarded, while my technical posts are removed - behind my back & without any justification!), I have withdrawn from this forum.

Re: Single carb on Mastiff AGAIN!

PostPosted: Thu Oct 08, 2020 10:44 am
by breakwellmz
DAVID THOMPSON wrote:we are all EARS keep us informed
Dave

not looking for big hp just some thing that runs NICE :smt023

wife keeps saying "sidecar" every time i go to work on any of the bikes


Fitted a 150 main jet today to replace the 180 that came with the carb, only a ten minute job. They took a bit of searching out as they had an M6 x 1mm pitch thread rather than M4 × 0.7MM that Keihin CVKs have. https://www.ebay.co.uk/itm/Keihin-Carbu ... 2749.l2649
It just gets better! Far cleaner running on the main jet with no `baulking` on big throttle opening gear changes. I`ve been getting a reasonable 46mpg (Imperial gallon) up to now so i expect that to improve as well. :D

Re: Single carb on Mastiff AGAIN!

PostPosted: Thu Oct 08, 2020 11:44 am
by DAVID THOMPSON
found JET on eBay in USA and its ordered from same place you got it in UK
thanks Dave

ouch on the price by the time it gets here...
but where i live every thing shipped in is expensive

and we lost an other bike shop here no one has any money

and riding a bike year around here is hard due to wet really nasty winters

Re: Single carb on Mastiff AGAIN!

PostPosted: Fri Oct 09, 2020 3:43 am
by Puffs
Following a biased and flawed moderator choice (someone posting aggressive personal attacks is rewarded, while my technical posts are removed - behind my back & without any justification!), I have withdrawn from this forum.

Re: Single carb on Mastiff AGAIN!

PostPosted: Fri Oct 09, 2020 4:44 pm
by breakwellmz
The carb was intended for a Harley hence the 180 main jet it came with, i just did a bit of research on main jet sizes for a range of 650cc plus singles and made an educated guess!