Last week there was a thread about Chevy/Pontiac 4-bangers. The conversation shifted to Harley side-draft carbs on a home-made manifold. Which Harley carburetors would be best for such a conversion ? I've been shopping the 'net and there are so many makes and types I'm not sure. I'm not looking for drag strip performance...more for smooth running and fuel efficiency. Being able to re-jet and synchronize linkages would be a plus factor too. Are they all gravity feed ? How would I pump fuel to them without using a cowl tank ?
Some guys use SU's on Harley's i think for smooth running & ecomomy you can't go wrong, adjustable main jet too! & they're cheaper & less troublesome than some of those Harley carbs.
i run an S.U. on my pan the suggestion 32Limey made is a sound one as you could just get an old mgb twin carb setup and adapt/make your own manifold.You'd have a combo made for a small 4 with linkages and all.All pre injection carbs that i've been around are gravity feed.
I've got SUs for my hopped up Model T 4 cylinder. I use'em on my Harleys too. Great Carburetor! For years I have wanted to build a long cross ram intake for a V-8 and use 4 SUs.
SJ over the years HD made several different styles.Knucs and Pans had linkerts.These were a sidedraft carb not much for performance,the biggest and last one being the M-74b.Next step was the tillotson or toiletson again not much for hyper use.They did make adjustable main jets for them I never had any luck with them AT ALL.Then came the Bendix a good carb but you couldnt do much with them like jettin they were pressed in I think.Then came the kien the best of the group.With these carbs you could jet for cam and exhaust changes.After that I have no idea the newer ones are FI and shit I dont know whatbike it is cause theres so many letters.For the 15 years I rode and built HDs from what I remember guys had the best luck with the kiens.I always ran 38 and 40 MM Mikunis they always worked well and jetting was a cinch with raising or lowering the metering rods.As far as fuel pressure goes Im sure you will be running like 4 at a time so that you will have to play with it using a regulator. Hope this helps a little.--Feder
FEDER....helps a bunch. Gives me a good idea of what to avoid That SU deal seems to make sense. I see Harleys converting to those. Thanks to everyone who replied.
Manyolcars i'm having an SU day today starting with a dream i had last night......multiple SU's on a flatty! i have no option but to give it a go being as there are so many of the damn things over here. Although i do run an S&S shorty on my panhead.
i have a 38mm Bendix on my sportster,it has the adjustable main jet kit in it.they also had a 36mm,they might also have a 40mm by now,if not it would be easy to bore it out.most of the accelerator pumps have 3 settings also.the real advantage IMHO is that they're cheap or free in a lot of cases,most of these idiots just buy the biggest S&S they can find and run that with too much cam and too big of exhaust pipes,resulting in what i call the "pig fart" sound.
since at first you would be in the experimenting phase I would go with a late model CV carbs there plentiful and mostly free (unless you really need them) cause the first thing everybody does is take them off. They have adjustable meterering and jets. you can adapt the bracket from a jap bike 4 banger to hold 4 carbs. Its a great frikin Idea. it would be cool to have 2 sets of 4 for a flatty with a homemade manni. FS
I'll second FS's reply, they are way cheaper than SU's and come in 40, 45(or 44?), and 51mm. They work on the sane principles as the SU but are easier, and cheaper to get parts for. -Jesse
i agree with fastsporty,go with a newer cv first, then a keihin if you can't get them.hell,you can probably go to any after market bike shop and tell them to save them for you.most people have them switched for an s&s,and just throw them out..
thought the carb set up at this ebay auction might interest you guys,and no it's not my car i wish................ http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=2457558202&category=6472
the guys are right, you probably find a few cv's cheap to experiment with, just from my own liking, the s&s shoerty "e" did my old shovel a whole world of nice, fullt adjustable and has an accelerator pump that is adjustable, the thunder header(tuned length 2 into 1 pipe) helped out too
I junked my CV on my old bike for an S&S, personal opinion would be to avoid them since they were problematic. The one thing you will have to do is make a rack with lever arms to adjust the choke and one for the throttle, could be pretty cool looking. Also, I would worry about having too many carbs (4) as they are designed for a 80 ci and under size motors.
I go along with Fast Sporty's recommendation on running CV carbs. Size and number - within reason - shouldn't create problems. They're a pressure differential carb and will only open as far as the engine demands. I ran a pair of 450cc Honda twin Keihins on an overbored and built 305cc (went to 331cc) Honda Scrambler. Enlarged the ports sorta like a funnel. Worked out pretty good and due to the slides only pulling up as far as pressure would let them, the bike never blubbered or bogged. Just pulled strong all the way through the gears. A good air filter is a must. I used K&N's.
Just my personal opinion but S&S's suck. And I've run many on the dyno. Mikuni's and a real exhaust make the most power for me. And drag pipes don't count as a real exhaust. The stock style CV carbs are great for real world reliability. But be worried about over carbing your motor if your putting multiple carbs on it.
I found a side draft carb in the pile of "stuff" in the back of the Elky I just bought and checked out the numbers on it. It's a L&L manufacturing M35 used on '46-'47 H-D knuckleheads. It's heavy bronze body, no accelerator pump, looks about as functional as a first generation S&S only smaller (1-1/2" throttle bore) makes a neat paper weight though!! To answer Burnedup's next Q, I'll trade it for a passenger car 94, but not by mail, the post office charges more to mail than a 94 core is worth!.)
[ QUOTE ] Does that mean I can give you $5 for it next time I see you? I have no 94's... [/ QUOTE ] No, trade only, (it's the game part of it you know?!) but I've got a Volvo license plate you can have back. If you're coming to the BBQ remind me to put it in the truck, like, the day before.
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