HPRE

Menu

Members Rides

Hanuman2


in
Members Rides

Welcome, Guest. Please login or register.
Did you miss your activation email?
December 22, 2014, 04:18:20 AM

Login with username, password and session length

 

Author Topic: C5 amal MKI tuning - season 2...  (Read 731 times)

strat71

  • Scooter
  • **
  • Posts: 82
  • Karma: 0
Re: C5 amal MKI tuning - season 2...
« Reply #30 on: December 14, 2014, 08:20:09 PM »
Thanks HoO,
you' been helpfull all the way...
Ben

High On Octane

  • Grand Gearhead
  • *****
  • Posts: 4346
  • Karma: 0
  • Go Fast & Look Good Doing It
Re: C5 amal MKI tuning - season 2...
« Reply #31 on: December 14, 2014, 10:17:58 PM »
No problem.  :)
Scottie J  ~  Bulldog Kustoms Denver  ~  1958 Enfield/Indian Trailblazer  ~  1959 Enfield/Indian Chief

swingarm

  • Neophyte
  • *
  • Posts: 49
  • Karma: 0
Re: C5 amal MKI tuning - season 2...
« Reply #32 on: December 16, 2014, 08:26:34 AM »
hey...
after a few weeks with the amal kit configuration, i finally ordered and received my amal MKI parts to start tuning it..
the stock combination is:
  • Throtle cutaway: 3
  • Needle Jet: 107
  • Needle position: highest
  • Main jet: 250
for memory, the stock jets don't work great on my bike 'cause i got a freeer downpipe and exhaust silencer.
i had to put the needle on the highest position because there was a big hole in the acceleration.
on this "best setting" stock configuration, the bike is running quite good at low throttle, but as soon as i'm opening the throttle there's not enough power (not as much as there was with the injection).
i'll have a lot of tries, will report the various ones...
Ben

This is what I'm running except for a 240 main jet. I think that's OK because full throttle seems right and seat of the pants better than EFI with an openish exhaust. There's the occasional spit back if the needle is lowered. The only nag is some minor surging at low throttle opening when doodling around town at an estimated 1500-1800 rpm. It's not clear to me what will fix this from reading tuning guides.

Does your low throttle performance show anything of this nature?
« Last Edit: December 16, 2014, 08:29:48 AM by swingarm »

strat71

  • Scooter
  • **
  • Posts: 82
  • Karma: 0
Re: C5 amal MKI tuning - season 2...
« Reply #33 on: December 21, 2014, 04:02:41 AM »
swingarm, i'm not sure if in understand what's your problem at low throttle (let me know), but speaking of low throttle setting, here's my experience...

with the 3 cutaway, the bike always stalled when coming back to idle after a heavy ride... very annoying.... (of course the idle was set as it should be)

i cured this problem by using a 3,5 cutaway (leaner). the bike don't stall anymore..

but by curiosity, i just checked the pilot screw position, and it's 3.5 turns out.  way off the recommanded 1.5 turn out.

i studied the different amal documents, and they recommand to put a smaller pilot jet, but on this carb, the pilot jet is pressed in so i can't change it...

maybe High On Octane can help on this point:
is 1,5 turn out on the pilot screw is a must do?
is 3,5 turns out too much?
should i live with it or do you think there's a problem here?

if so, here's how i could get a best pilot screw position: looks like the pilot jet is big, injecting a lot of fuel, so, as i can't change the pilot jet, maybe i could put an even bigger cutaway (4), even leaner to compensate for the extra fuel?????? what do you think?

Ben (looks like learning to tune a carb is a long and complex process ;) )

High On Octane

  • Grand Gearhead
  • *****
  • Posts: 4346
  • Karma: 0
  • Go Fast & Look Good Doing It
Re: C5 amal MKI tuning - season 2...
« Reply #34 on: December 21, 2014, 01:07:42 PM »
Ok, so the pilot circuit on the MK1 is the biggest problem that the concentric carbs haves.  As you mentioned, the pilot jet is pressed into the carb, which I think is stupid.  This is also where tunings really start to vary from bike to bike.  You state that the air screw on your bike is 3.5 turns out.  MY air screw?  Less than a 1/8 turn out and it chokes, more than 3/4 turn out and it starts popping.  It seems to be happiest at about 1/3-1/2 turn out.  But honestly, I have never gotten a "good tune" out of this carb, only "good enough".  I have never been so disappointed in spending almost $200 on a brand new carb.  I will likely be buying a Mikuni VM32 or TM32 (or 2 of each) in the next couple of months.  You can actually buy 2 VM carbs for the same price as one Amal.
Scottie J  ~  Bulldog Kustoms Denver  ~  1958 Enfield/Indian Trailblazer  ~  1959 Enfield/Indian Chief

SteveThackery

  • Inveterate tinkerer
  • Grease Monkey
  • ****
  • Posts: 281
  • Karma: 0
  • "If it ain't broke, keep fixing it until it is."
Re: C5 amal MKI tuning - season 2...
« Reply #35 on: December 21, 2014, 01:58:01 PM »
Ok, so the pilot circuit on the MK1 is the biggest problem that the concentric carbs haves.  As you mentioned, the pilot jet is pressed into the carb, which I think is stupid.  .....   But honestly, I have never gotten a "good tune" out of this carb, only "good enough".  I have never been so disappointed in spending almost $200 on a brand new carb.  I will likely be buying a Mikuni VM32 or TM32 (or 2 of each) in the next couple of months.  You can actually buy 2 VM carbs for the same price as one Amal.

I absolutely agree with every word of that.  The Amal Mk1 Concentric is a really rubbish carb* and why anybody would sell them - or want to buy one - is a total mystery to me.  As HOC says, the best you will get is "good enough", but never "good".

Actually, I can think of one reason to sell them: where authenticity is important.  But as an after-market fit on a bike which never had them in the first place?  WHAT?? 

The Mk2 Concentric is vastly superior (although for silly money), as is anything from the Mikuni range.  For really softly tuned bikes like ours I love a CV carb, and the one fitted to the Electra X was perfect for the job (not for performance, but for beautiful driveability).

*Actually the Mk1 isn't bad at all for full-throttle performance.  That's why they look pretty good on a dyno.  But how often do you get full throttle on the road?
2014 B5, stock apart from disabled auto-decomp.  Also ride a Kawasaki Versys 650 for everyday use.

Previous:
'06 ElectraX (Good bike, had no trouble at all)
'02 500ES (Fully "Hitchcocked" - 535, cams, piston, etc - and still a piece of junk)

High On Octane

  • Grand Gearhead
  • *****
  • Posts: 4346
  • Karma: 0
  • Go Fast & Look Good Doing It
Re: C5 amal MKI tuning - season 2...
« Reply #36 on: December 21, 2014, 02:03:28 PM »

*Actually the Mk1 isn't bad at all for full-throttle performance.  That's why they look pretty good on a dyno.  But how often do you get full throttle on the road?

Actually, I'm at WOT a lot, and I have always felt that the bike was weak at WOT.  I should be able to Ton Up, and I have only gotten a best speed of 95mph.
Scottie J  ~  Bulldog Kustoms Denver  ~  1958 Enfield/Indian Trailblazer  ~  1959 Enfield/Indian Chief

strat71

  • Scooter
  • **
  • Posts: 82
  • Karma: 0
Re: C5 amal MKI tuning - season 2...
« Reply #37 on: December 21, 2014, 06:14:59 PM »
i heard you brothers, as you know , the amal came with the kit, and i try to use it as much as i can before trying something else... but i hear you... my main concern with the mikuni is the fitting to my bike, there don't seem to be lot of people who have tried it, i don't want to buy a carb and discover that it does'nt fit under the gas tank... but it's definitly an option.

anyway , back to my question, i just realize that the cutaway won't help on the idle circuit, stupid assomption... but it may help on merging the cutaway area to the needle area... will try... and report...
Ben
« Last Edit: December 21, 2014, 09:06:15 PM by strat71 »

swingarm

  • Neophyte
  • *
  • Posts: 49
  • Karma: 0
Re: C5 amal MKI tuning - season 2...
« Reply #38 on: December 21, 2014, 11:45:13 PM »
swingarm, i'm not sure if in understand what's your problem at low throttle (let me know), but speaking of low throttle setting, here's my experience...

with the 3 cutaway, the bike always stalled when coming back to idle after a heavy ride... very annoying.... (of course the idle was set as it should be)

i cured this problem by using a 3,5 cutaway (leaner). the bike don't stall anymore..

Thanks Ben. You've confirmed what I thought the various guides were saying. I've improved the stalling tendency by upping the idle but it's still not trustworthy and who wants high idle on a long stroke motor? Looks like the bigger cutaway will do it. My pilot screw is nothing like 3.5 turns out so it seems OK on that front.

cheers

strat71

  • Scooter
  • **
  • Posts: 82
  • Karma: 0
Re: C5 amal MKI tuning - season 2...
« Reply #39 on: Today at 03:03:10 AM »
Thanks Ben. You've confirmed what I thought the various guides were saying. I've improved the stalling tendency by upping the idle but it's still not trustworthy and who wants high idle on a long stroke motor?
never heard of improving the stall with high idle method, but i heard that amal is lean if you search for the highest rpm with pilote screw... you should add a 1/4 turn on the richer side to be good..
anyway, you're right nobody wants high idle on enfield bike, mine idle great at 1050 per minute...
let us know how it turns with other cutaway
Ben