Author Topic: What Carb to breathe fire on a daily ?  (Read 424 times)

Online AnthonyA

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What Carb to breathe fire on a daily ?
« on: 12.12. 2019 15:24 »
Hi fellas,

Currently in the rebuild process, I looked at the ol' Monobloc, and the huge drip tray. So I searched why such ski-ramp was needed, and it appears our old carbs can have character.

Anyway, I know some people love the old Amal, ... but I want simplicity, reliability and performance. I don't really care about being period correct, I want to ride as I please.
Yes I'm a bit greedy.
We're in 2019, and I believe there are many options available these days to tick these boxes.
The mikuni on my Honda never gave me any trouble.

So yeah I could slap any Mikuni on the 650 and call it a day, but we all know it's not that simple.

I've heard that a Mikuni VM 34 (with a main jet 260, pilot jet 35, needle jet P6) was the deal, but for Triumph 650.

Therefore I come seeking tips, tricks and tales of experience from you guys.
Thanks !
A10 Road Rocket (swing-arm)

Offline beezermacc

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Re: What Carb to breathe fire on a daily ?
« Reply #1 on: 12.12. 2019 16:16 »
I have recently bought a couple of carbs from 'Allens performance'  www.allensperformance.co.uk
They supply Mikunis ready jetted for any model and I've found them very helpful. The disadvantage with a Mikuni is you can't tickle it so it takes a couple of kicks to get fuel sucked in. If you buy the full kit which includes manifold and air filter you just bolt it on and away you go. The whole kit is a reasonable price, can't remember how much, but it seemed reasonable at the time. If you buy the kit I would recommend not buying the two allen head bolts they supply to bolt the manifold to the head. The price Allen's charged for these two bolts was absolutely ridiculous (something like £30 if I remember correctly) because they have to be made on a lathe, apparently. I went to our local engineers' suppliers and bought some allen head bolts and skimmed the heads down myself. The two bikes I have these carbs fitted to run really well and start easily

No doubt other forum members will have positive experiences of other non standard carbs and will be interesting to hear their views.
Priory Magnetos Ltd - A10 spares, magneto and dynamo refurbs. www.priorymagnetos.co.uk

Online Rex

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Re: What Carb to breathe fire on a daily ?
« Reply #2 on: 12.12. 2019 16:28 »
Amal Premier. How much "performance, reliability and simplicity" do you need? *smile*

Online Billybream

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Re: What Carb to breathe fire on a daily ?
« Reply #3 on: 12.12. 2019 16:33 »
In a similar situation to you earlier this year, my old concentric was well past it's best, tried various improvements and mods to it, but pilot circuit was main issue, difficult starting and very wet finger through tickling, which could be considered a hazard.
So asked for advice, and several suggestions, but after alot of research choose PWK 30 Flat Slide, after initial setting and some jet changes, this carb is a joy, no tickling, just fuel on, enricher on and she starts first kick, runs great, so very pleased. Jets and spares are readily available, existing cable fits, just some replumbing to fuel lines and addition of fuel filter and air filter.
1960 Super Rocket, owned since 1966, back on the road 2012 after being laid up for 29yrs.

Online Billybream

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Re: What Carb to breathe fire on a daily ?
« Reply #4 on: 12.12. 2019 16:39 »
Sorry wrong picture
1960 Super Rocket, owned since 1966, back on the road 2012 after being laid up for 29yrs.

Online RDfella

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Re: What Carb to breathe fire on a daily ?
« Reply #5 on: 12.12. 2019 17:26 »
Owned Mikunis, Dellorto, Amal 276, monobloc & concentric (Mk1, 1 1/2 and 2), bing, weber, zenith ..... In my opinion, the monobloc is the simplest, easiest to tune and most reliable for our old bikes. Mikunis and webers (not that you'll be using the latter) have so many variables they take ages to tune and then you're never sure it's optimal. If you can't tune a monobloc in an hour or so you're not trying.
'49 B31, '49 M21, '53 DOT, '58 Flash, '00 Firestorm, Weslake sprint bike.

Online berger

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Re: What Carb to breathe fire on a daily ?
« Reply #6 on: 12.12. 2019 17:45 »
here we go , "if you can't tune a monoblock in an hour your not trying" well bless my soul but I tried getting my shooting star to tick over {nicely without spitting back and other annoying little gremlins} on and off for 2 years using two old monoblocks and a mixture of jets , new slides etc etc. I gave up and fitted a mikuni and bingo me and betsy beezer are happy bunnies ;)

Online AnthonyA

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Re: What Carb to breathe fire on a daily ?
« Reply #7 on: 12.12. 2019 18:03 »
Thanks guys !

It's not much the tuning, it's the day to day use, for years to come.
I've had the Mikuni on the Honda for 5 years, I tuned it once (easy peasy), it never dripped on me or issues with the slider, or any kind of issue in fact. I don't want to fiddle with it or worry about it when I'm riding on the other side of Europe...

EDIT:
So guys, if your recipe works, can I have it ? Carb model, jets and stuff. Thanks !
A10 Road Rocket (swing-arm)

Offline Klaus

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Re: What Carb to breathe fire on a daily ?
« Reply #8 on: 12.12. 2019 19:12 »
I have a Mikuni Carb Set left from my Scrambler and would sell it complete for 250 Euro with shipment.

cheers Klaus


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Online RDfella

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Re: What Carb to breathe fire on a daily ?
« Reply #9 on: 12.12. 2019 19:19 »
Maybe I should clarify what I meant by 'tuning'. Getting a correctly jetted amal running properly is simple. Try a main jet up or down from the existing one and maybe move the needle a notch and adjust the pilot screw and job’s done. Cutaway and pilot jet shouldn’t need changing nor should the needle jet. But when you look at the bewildering array of options for a mikuni it's difficult to know where to start. There's something like forty different needles never mind the other jets.
I've always figured it's more likely to get an engine running better with a simple carb than one where perfection is possible but almost impossible to obtain because of complexity. On mikunis you even need a special tool to get the float out (the spindle is pressed in and if you try to punch it out you’ll likely break the carb body). Only chose mikunis for my latest project because monoblocs don't go big enough and I'm not a concentric fan. I'm dreading setting them up.

But back to the bike in question - we're not talking GP or TT carbs here, so monobloc would be my choice. I have them on several old bikes. In my view concentrics are cheap and nasty.
'49 B31, '49 M21, '53 DOT, '58 Flash, '00 Firestorm, Weslake sprint bike.

Online muskrat

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Re: What Carb to breathe fire on a daily ?
« Reply #10 on: 12.12. 2019 19:38 »
G'day Ant.
I too have PWK 30's (a pair on the Cafe). Simple and cheap and should run straight out of the box on a std motor. https://jrcengineering.com/technical-support/jrc-pwk-carb-instructions/  In my case trying to get a pair to run was a chore, like Mikuni's there's a million needles to choose from.
But as RD said a well set up mono is simple and easy and will take you around the world.
Cheers
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Offline mikeb

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Re: What Carb to breathe fire on a daily ?
« Reply #11 on: 12.12. 2019 22:36 »
Quote
two old monoblocks and ... I gave up
berger maybe the word 'old' here is a clue. i'm not strong on this stuff tho could not get the old monobloc right on by a10 or the old 289 on my b33, despite new slides, needles, jets, floats etc. i guess i was overpowered by well-worn 60 year old muck metal and the efforts of many previous owners. but buying new monoblocs from burlen was fairly close to plug and play for both bikes.

Anthony I think the best way to achieve fiery performance from an A10 is buy a modern
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Offline beezermacc

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Re: What Carb to breathe fire on a daily ?
« Reply #12 on: 12.12. 2019 23:06 »
Thanks guys !


EDIT:
So guys, if your recipe works, can I have it ? Carb model, jets and stuff. Thanks !
Just go on the Allens website and look at their recommendation for your bike.
Priory Magnetos Ltd - A10 spares, magneto and dynamo refurbs. www.priorymagnetos.co.uk

Offline Kickaha

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Re: What Carb to breathe fire on a daily ?
« Reply #13 on: 13.12. 2019 05:08 »
On mikunis you even need a special tool to get the float out (the spindle is pressed in and if you try to punch it out you’ll likely break the carb body).

The Mikunis I have had you could pull it out with your fingers or needle nose pliers

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Online Black Sheep

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Re: What Carb to breathe fire on a daily ?
« Reply #14 on: 13.12. 2019 06:55 »
The good old monobloc has worked for me for the best part of 100,000 miles. Every move from standard leads to more complication when it goes wrong...
2 twins, 2 singles, lots of sheep