Which carb to go with?
- Thread starter beefco
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Google "Dellorto PHF36".
Hows about one of these? One should be awesome. Mikes xs has them also and parts.
Two may require some slight splaying.
http://www.bevelheaven.com/stuff-for-sale-phf.htm
Hows about one of these? One should be awesome. Mikes xs has them also and parts.
Two may require some slight splaying.
http://www.bevelheaven.com/stuff-for-sale-phf.htm
Do you mean the Keihin FCR 35mm's? I have a single 40 pumper and I know the accelerator pumps can be toughy and how easy it is to foul the plug if you over use it at stop lights. I know that those 2 35's have that same issue, but oh, what performance. Low, Hi, and the mid range with the right cam is unbeatable, IMHO.Snorton74 said:
Those Dellorto PHF36's look like a viable option though, at about 2/3 the cost if they can be made to fit.
I AM 100% with you Dave.
My Trident is living proof of this ~I tinkered with Mikunis, even Webbers ~ and ended up with a very tidy set of Amals ~ and a spectacular fuel economy~
The humble original Amal may take some time to tweak and get just right ~ but they are simple, effective and race proven as well ~
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pvisseriii said:
Not the Keihin's, something unique. Ya gotta take your bike to CO to get it installed. He's putting it on the series of cafe bikes he's building, one of which the Boz Bros. rode on Cafe Racer. Pretty f'n sick bike, and you can tell they feel the same. I like the Dellortos, and still want a Jota with em on it. They'd probably work pretty well on the Roadster too.
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If they only still made these in the accelerator pumper model. I've got a 38 mm on hand to try some day. Biggest pain in the ass carb to dial in, but once it is, reports say oh la la...
http://www.650motorcycles.com/QwikSilver.html
Well lookie here they do!
http://www.magicracing.com/Edelbrock-Qw ... p_421.html
The new Pumper Series carburetor is designed for today's high-performance TRX450R four-stroke engine. The accelerator pump allows crisp throttle response and added external tuneability for applications that demand a broad power band. QwikSilver Pumper Series carburetors offer these benefits along with the superior features of the original QwikSilver carbs.
Price: $480.95
Sale Price: $349.99
http://www.650motorcycles.com/QwikSilver.html
Well lookie here they do!
http://www.magicracing.com/Edelbrock-Qw ... p_421.html
The new Pumper Series carburetor is designed for today's high-performance TRX450R four-stroke engine. The accelerator pump allows crisp throttle response and added external tuneability for applications that demand a broad power band. QwikSilver Pumper Series carburetors offer these benefits along with the superior features of the original QwikSilver carbs.
Price: $480.95
Sale Price: $349.99
I have had very good luck with the straight Keihin cr which has the same spread as the Yam 650 used in many applications.
They are straight HOOKUP TO RUBBER MANIFOLDS( same as MK ii Amals). must use at least 2,5 slides but easy to tune and never change once setup. 750 - 33's for combat or 31's, use 31's or even 29's for standard 750's . Don't know about 850's but 31 or 33 should work. These are full smoothbores and were the best before the 'better' fcr's came out. typically your mikuni amal main jetting is a good spot to start (mains-200=230 to start and idle jets at 20.) you may have to keep slid around 2,5 -3,0. Must use slide as
off idle to 1/4 throttle accel. pump but mileage is still near 50 mpg. in my Combat.
They are straight HOOKUP TO RUBBER MANIFOLDS( same as MK ii Amals). must use at least 2,5 slides but easy to tune and never change once setup. 750 - 33's for combat or 31's, use 31's or even 29's for standard 750's . Don't know about 850's but 31 or 33 should work. These are full smoothbores and were the best before the 'better' fcr's came out. typically your mikuni amal main jetting is a good spot to start (mains-200=230 to start and idle jets at 20.) you may have to keep slid around 2,5 -3,0. Must use slide as
off idle to 1/4 throttle accel. pump but mileage is still near 50 mpg. in my Combat.
Fast Eddie
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pete.v said:
Hi Pete, forgive me if I'm about to say something you already know... But you do know that Amal MK2s and Amal MK2 smooth bores are two different carbs?
The standard MK2 has the anodised slide as you mention, the smooth bore has a chromed brass slide and is a very thin section, as it needs to be to pass between the smooth bore body internally machined slots.
The smoothbore is a great carb, but quite expensive. And I'm pretty sure they were only made in 34, 36 & 38mm. I'm not sure as to current availability, they tend to be made in small batches due to their limited demand.
The smooth bore is often not desired on the road as there is no provision for a tickover, the body cannot be adapted either as a screw in slide adjuster would damage the thin slides.
I've seen people make external gantries for these and incorporate a tickover facility that way.
pete.v said:
No one except for the truly masochistic goes the twin Mk2 route and I can proudly count myself amongst that small number.
I really don't think it's worth the effort and it took a lot of effort to get them anywhere close to sorted, any potential benefits are pretty marginal on the road.
I'll add my vote to the Mk1 Amal camp. no personal experience but the premiere type are the route I would go if I was in the market.
Rich
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+1DogT said:
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If it's a single modern carb you want, I'd check out Jim's single flat slide PWK.
Jim's carb and 2-into-1 manifold is much more compact than the Mikuni setup, and I'd wager the more modern flat slide design will perform better. I swapped a single Mikuni from my 850 for dual PWK's largely for aesthetics (sorry, it just looks wrong) but was very impressed with the performance gains of the dual flat slides, and I can putter around town just fine thank-you. Yeah, the Amal Premiers look correct if you want a museum piece, but they're still a 50 year old design with a goofy + complicated choke setup (slides within slides? Really?).
And If you don't care about aesthetics, then why ride a 45 year old Brit bike anyway?
Does anyone really think this looks good? C'mon. It sticks out like a sore thumb on an otherwise beautiful engine.
Jim's carb and 2-into-1 manifold is much more compact than the Mikuni setup, and I'd wager the more modern flat slide design will perform better. I swapped a single Mikuni from my 850 for dual PWK's largely for aesthetics (sorry, it just looks wrong) but was very impressed with the performance gains of the dual flat slides, and I can putter around town just fine thank-you. Yeah, the Amal Premiers look correct if you want a museum piece, but they're still a 50 year old design with a goofy + complicated choke setup (slides within slides? Really?).
And If you don't care about aesthetics, then why ride a 45 year old Brit bike anyway?
Does anyone really think this looks good? C'mon. It sticks out like a sore thumb on an otherwise beautiful engine.
I really like the dual flat slide carbs from Jim Schmidt (JSMotorsport.com). Jim was always there to help with my questions and he really knows what he's doing. I occasionally find myself checking to see if the bike is running at stop lights because it's idling so well.
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