Author Topic: which carburettor?  (Read 405 times)

Offline RDfella

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which carburettor?
« on: 31.10. 2024 17:36 »
Used a variety of carbs over the years, but always liked the monobloc. Very easy to tune. Somehow the concentric looks spindly, and the MK 2 big and ungainly. I found Mikunis a nightmare, jet prices through the roof and 3 weeks wait every time one needs another. Bing too rare, etc.
Presently trying to decide what to use for my project (2 x 1 1/8"). Trouble is, monoblocs are a tad expensive to fit on an experimental engine which will presumably run, but may not be the dbs. I've heard comments on PWK, but have no real info. eg what are parts like to get in the UK?
Ideas?
'49 B31, '49 M21, '53 DOT, '58 Flash, '62 Flash special, '00 Firestorm, Weslake sprint bike.

Online CheeserBeezer

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Re: which carburettor?
« Reply #1 on: 31.10. 2024 20:17 »
I've used Mikunis on two projects recently and found them relatively easy to set up, mainly because they are attached by an intake rubber which enables the carb to be rotated or removed easily to access the needle and slide if necessary. The monobloc is so close to the top frame tube it has to be completely removed to get the slide and needle out without damaging parts. I, and others can offer a starting point for jet sizes so, maybe, buy a clutch of jets in one hit before tuning. I've heard good reports of PWK carbs and they're relatively inexpensive. They're on Ebay and the listings contain the name of the distributor of the carbs and jets.

Offline rocker21

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Re: which carburettor?
« Reply #2 on: 01.11. 2024 09:47 »
i sell the JRC engineering  version of a PWK and spares are no problem, keep most of them in stock and they are a lot cheaper than a new monoblock or anything else apart from the wassel version of a concentric, they work well, how the yanks do them for that price i do not know, a 30mm carb is about £150 + postage,  sold loads of them over the years.
1960 A7S motoguzzi Monza 500, motoguzzi V7III special, new triumph speed 400
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Offline rocker21

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Re: which carburettor?
« Reply #3 on: 01.11. 2024 11:20 »
a lot of the PWK carbs on ebay are copies made in china, they are very cheap and not so well made, seen a couple of them when i got someone trying to send me one back under warranty and i had to tell him politely to go away , he had bought one from me but the one he sent back was a china copy!!!
there are some real ones on ebay from the USA which are priced very similar to what i sell mine for, but you will have to pay the customs fees which add at least 20% to the cost plus the postage from the usa,
1960 A7S motoguzzi Monza 500, motoguzzi V7III special, new triumph speed 400
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Online Rex

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Re: which carburettor?
« Reply #4 on: 01.11. 2024 11:35 »
Said this more than once, but Amal Premier for me every time. Cheap and available spares, and easy to tune.
Never seen a china carb though Rocker. I bet that would chip easily..

Offline RDfella

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Re: which carburettor?
« Reply #5 on: 01.11. 2024 20:05 »
Thanks for that, chaps. Having spent months and £sss trying to fit a pair of new Mikunis, afraid I can't agree regarding them. One would need a full box of jets (there's hundreds) plus access to a dyno. Re PWK, how to know one's not buying a cheap Chinese one, but charged a hundred or more?
A pair of second-hand monoblocs is looking good ....
'49 B31, '49 M21, '53 DOT, '58 Flash, '62 Flash special, '00 Firestorm, Weslake sprint bike.

Offline rocker21

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Re: which carburettor?
« Reply #6 on: 01.11. 2024 20:26 »
Most of the Chinese stuff is very cheap, buy from a reputable dealer who will have all the parts etc, a lot of the Chinese ones were sold by OVO,  the original pwk carbs were made by kehlin (not sure if I spelt that right) and a real pwk still uses their jets
1960 A7S motoguzzi Monza 500, motoguzzi V7III special, new triumph speed 400
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Online Rex

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Re: which carburettor?
« Reply #7 on: 02.11. 2024 10:55 »
A pair of second-hand monoblocs is looking good ....

Depends just how "second hand" they are. Worn slides makes them useless until they've been reconn'd, then there's worn needle jets, chewed up/seized pilot jets, worn top cap threads etc etc.

Offline Catz

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Re: which carburettor?
« Reply #8 on: 02.11. 2024 11:49 »
A pair of second-hand monoblocs is looking good ....

Depends just how "second hand" they are. Worn slides makes them useless until they've been reconn'd, then there's worn needle jets, chewed up/seized pilot jets, worn top cap threads etc etc.

Yep. Buy cheap buy twice. I was talking to the lads on the Amal stand at the Stafford Show this year and they quoted me £300 for a new carb for the A10 and a quick look on their website confirms this. I'd buy one at that price if i needed one.
Crewe, Cheshire, England 1960 A10

Offline Joolstacho

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Re: which carburettor?
« Reply #9 on: 02.11. 2024 22:32 »
I agree that the JRC is a brilliant little carb.

Offline olev

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Re: which carburettor?
« Reply #10 on: 03.11. 2024 21:47 »
I also agree the JRC is a great carby.   
however ..... the plastic needle retainer on mine recently twanged across the shed, never to be seen again.
I bought a complete PWK/OKO 28mm carby off ebay for about A$35 with free postage just to get this bit.
I must admit I was surprised with the quality and the fact the thing appears identical with my JRC.
Years ago it used to be japanese crap, then korean rubbish. now it's chinese junk.
I think a lot of chinese stuff has moved on.
Ebay sells a 34mm version for less than A$50 and a set of 20 main and pilot jets for A$20.
RD, if it was me, I'd be buying a couple of these and a set of jets.
little risk and possible huge value. I think you would be surprised.
cheers