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Will these carbs work?

Heavy_Arms

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Picked up a 74 750 without carbs and then bought a set that supposably came off a super sport. Will post pics of the carbs to get confirmation if that is what they are, but assuming it's right, will those carbs work on the bike?
 
Yes pictures for sure if you can. The 74 came with round top carbs. If they are supersport carbs then they are the later model carbs and where never on the 74. The intake rubbers are a different size as well as the air filter side.
 
I have 3 carb boot that came with the bike and I did notice they didn't fit on the carbs themselves but I thought they were just dried up. Here's a picture of the one's I bought.
PhotoJul3124420PM.jpg
 
Those carbs are later model and didn't come on your bike. With the correct rubbers and air cleaner you should be able to make them work. I bet the rubbers you got with the bike are the ones for the correct carbs.
 
Those carbs are later model and didn't come on your bike. With the correct rubbers and air cleaner you should be able to make them work. I bet the rubbers you got with the bike are the ones for the correct carbs.

Yeah the boots I have are definitely for the 74. I can just go out and by some couplers since I need a new set of boots anyway and I'm sure they'll fit. My main concern was just the throttle cables and mounting points being the same.
 
I believe you should be able to use the 74 throttle cables on these carbs. You will have to get a choke cable, as the 74 used a lever on the choke and these had a cable. Also you will need air cleaner box or specific filters for these carbs and not the 74 carbs.
 
I believe you should be able to use the 74 throttle cables on these carbs. You will have to get a choke cable, as the 74 used a lever on the choke and these had a cable. Also you will need air cleaner box or specific filters for these carbs and not the 74 carbs.

ALright cool thanks for the info. M big question is also are these better carbs than the ones that would come on the 74. When I told the seller they were the wrong carbs he said they came of a super sport and were a better performing part. So is it worth making these work or should I just send them back in exchange for the year appropriate piece?
 
I've got those carbs on my K6. Just get the right boots (the later ones, kinda hour glass shaped) and your golden.

What does the number on the side of the carb #4 say? If they're for the A model they will be slightly different jetted than the ones for K and F models. PD44A and PD43A is for the automatic (model A).
If you're runnin' pods and free flow exhaust you'll need to rejet anyways..
I'm runnin' pull cable only, but these carbs were setup for one push and one pull cable. I don't need the push cable, they work just fine without, if you keep 'em clean and greased in the right spots. You can get the MotionPro cables at Cycle One for cheap. Kate there will help you out.

Hope this helped some.
 
Yes I think they can be a better performing carb, they do have an accelerator pump as the old ones don't, they are slightly bigger. If you have to tune them they are a bit more of a problem because the idle jets are pressed in and not as easy to find different sizes and the needle is adjusted with shims. As long as they look in good shape I would probably use them. What are you going to be doing to your bike? Is it stock motor and exhaust? Exhaust and air cleaner changes have a big effect on the jetting, if you are close to stock you can probably run them the way they are but if you run pod filters or different exhaust you will more than likely need to do some re jetting.
 
Woah.. You guys type way faster than me.

If you're not doing a restoration to bone stock, I'd say go with those carbs since you've already got them. They're a little bit trickier to dial in, but works great when done right (Or so I'm told - still struggling with a clogged pilot line on mine).

But then again, you've already got 3 boots for the round tops, and if those boots are good, and you could exchange these carbs for a set of roundtops for free, then you'd only need to get 1 more boot. Less hazzle maybe? I don't know..
 
Ok, I'm one step behind all the way - typing at the speed of a three year old. Dirtdigger is spot on here so I'm out. Good luck anyhow!
 
The hour glass shaped boots look straight where the older ones have a bend in them. Do the later model motors have the same intake, like how they are slanted inwards.
 
Yes the heads are basically the same, the boots should look the same just different size on the carb side.
 
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Difference between the carb boots:
K model with the round top carbs: http://www.use.com/images/s_2/HONDA_CB750_K4_CARBURETOR_BOOTS_c1512f564adf411ddd1b_2.jpg
F (and some K) model with the keyhole carbs: http://www.roofis27.com/motorcycle/12_05_30/041.JPG

I did actually get a set of pre 1978 carb boots to fit on my keyhole carbs, but they tilted to much. So I switched to the right ones.

Dunno if this helps though..

All the info helps a lot. Thanks man. These are the boots you're saying that I need??
http://www.ebay.com/itm/79-83-CB750...ies&hash=item53ee1c11a0&vxp=mtr#ht_650wt_1249
 
I'm not 100% sure on that. Could you post the number on your carbs? Then I'll know for sure.

(I actually think the ones you've posted here is for a DOHC and not a SOHC.)
 
I believe you should be able to use the 74 throttle cables on these carbs. You will have to get a choke cable, as the 74 used a lever on the choke and these had a cable. Also you will need air cleaner box or specific filters for these carbs and not the 74 carbs.

I dont think this works.. I have a set of oem cables that are new to prove it..somewhere..lol I remember buying the same ones as my brother did for his bottlecaps thinking nothing about the carb differences(mine are PD's) and once I went to install the free play was off for both//or atleast one of them.. The bottlecaps are a "butterfly like" push-pull system requiring minimal freeplay on the carb side, where as the PD carbs have to wrap around a large wheel like acutator requiring much more free play...
 
Mine did fit...dont know what to tell ya:shrug: Maybe my cable was stretched enough. I guess get whatever cables you need for whatever carb you are going to use.
 
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