Topic: Carbs for a '74 cb750 (k?)

[kerryb]

I got a 74 750 motor that appears to be good.  What carbs can be used to try it out.  I have pd42b's  w/ k8 boots, but something tells me the spacing will be incorrect.  Comments?

[Terry in Australia]

No mate, they'll go straight on, I had a set on a K2 engine many moons ago and they work well. Be aware that they run extremely lean (they were introduced to pass EPA regs, not improve performance) so you'll need to install a K7/8 airbox too, with a filter (OEM works best, K&N's are great but make them run too lean without rejetting) but the K4 sidecovers will crack if you try to install them with the slightly wider K7/8 airbox. Your standard K4 throttle cables will work with the PD's, but you'll need a K7/8/F2/3 choke cable and bracket. Cheers, Terry.

[kerryb]

That's great news, all my other 750 stuff is k7-8.  I'm familiar with with pd42b's  because that's all I have.  Now that enginless roller has at least a chance to see the street again...someday (sigh)
Thanks a bunch for the info Terry.

p.s.  when I visit down under next year, you'll have to let me know what you need that's too costly to ship, but it has to fit in a carry-on!

[Terry in Australia]

Thanks mate, that's really nice of you! Yep, get that bike running and ride it, I hate long drawn out resto's, so I try to do one build every winter, which is testing the extent of my attention span.

[desertrefugee]

Long drawn-out Restorations. Unfortunately, I apparently don't know how to do them any other way. Frankly, the real constraint is time. Precious time. 

So, I begin to think of the process as therapy. The end result is a bonus.

If that's true, then I will soon be getting lots of therapy with the K4 and F3 basket cases that I recently acquired.

... speaking of which and the reason why I poked into this thread, the carbs I have for the 74K are in decent shape but need overhaul. The rack from the 78F are a disaster. Would it be Blasphemous if I put the 74 carbs on a 78 Super Sport?

[Terry in Australia]

Long drawn-out Restorations. Unfortunately, I apparently don't know how to do them any other way. Frankly, the real constraint is time. Precious time. 

So, I begin to think of the process as therapy. The end result is a bonus.

If that's true, then I will soon be getting lots of therapy with the K4 and F3 basket cases that I recently acquired.

... speaking of which and the reason why I poked into this thread, the carbs I have for the 74K are in decent shape but need overhaul. The rack from the 78F are a disaster. Would it be Blasphemous if I put the 74 carbs on a 78 Super Sport?

The hardest thing would be getting them to fit mate, the spigotts on the F2/3 heads are larger od than the k series bikes and the F/F1. The rubber insulators are a tight fit on the smaller spigotts, but you may be able to heat them enough to stretch them over? There should be plenty of F2 carbs around though, there are plenty of dead F2's, I've got several sets here.

[vik351]

No mate, they'll go straight on, I had a set on a K2 engine many moons ago and they work well. Be aware that they run extremely lean (they were introduced to pass EPA regs, not improve performance) so you'll need to install a K7/8 airbox too, with a filter (OEM works best, K&N's are great but make them run too lean without rejetting) but the K4 sidecovers will crack if you try to install them with the slightly wider K7/8 airbox. Your standard K4 throttle cables will work with the PD's, but you'll need a K7/8/F2/3 choke cable and bracket. Cheers, Terry.

So Terry,you could perhaps advise me on fitting K7 carbs and head to a 1977 Hondamatic 750A , the fella I am getting them from dont like small talk 
So can I use my Hondamatic carby bracket with the idle up solenoid and the throttle cables with out too many head whatsanames...

I believe these(K7 carbs) also have the fuel squirter like my stock Hondamatic jobs...



Hondaman recommends the idle up for the slusher if ya change carbys on the auto

Some use round tops and put up with the flat spot, bugger that if I can help it

vik...

[desertrefugee]

Thanks Terry.  Appreciate the tip on the carbies.
 
I believe we've communicated before. Some time ago, there was an Australian Terry knocking around over on the Naked Goldwing forum.  That Terry commented on my '78 build thread.

[kerryb]

Thanks mate, that's really nice of you! Yep, get that bike running and ride it, I hate long drawn out resto's, so I try to do one build every winter, which is testing the extent of my attention span.

I tend to feed my A.D.D., I have a few bikes to ride, (in case something needs work) and I have several project bikes going all the time.  I don't finish any more than one bike a year (or more!) but I'm never bored while looking/waiting for parts, I just drag a different project out and work on that.  I'm just playin' really.

[desertrefugee]

    Sounds familiar.

[Terry in Australia]

Thanks Terry.  Appreciate the tip on the carbies.
 
I believe we've communicated before. Some time ago, there was an Australian Terry knocking around over on the Naked Goldwing forum.  That Terry commented on my '78 build thread.

Yeah mate, guilty as charged, I donated my GL1200 to charity in 2015, and stopped looking at that forum around the same time. This forum is a bit different for me, I'm always buying, building and (occasionally) selling CB750's, so this is the best resource for learning about them, and hanging out with other SOHC4 tragics.

[Terry in Australia]

No mate, they'll go straight on, I had a set on a K2 engine many moons ago and they work well. Be aware that they run extremely lean (they were introduced to pass EPA regs, not improve performance) so you'll need to install a K7/8 airbox too, with a filter (OEM works best, K&N's are great but make them run too lean without rejetting) but the K4 sidecovers will crack if you try to install them with the slightly wider K7/8 airbox. Your standard K4 throttle cables will work with the PD's, but you'll need a K7/8/F2/3 choke cable and bracket. Cheers, Terry.

So Terry,you could perhaps advise me on fitting K7 carbs and head to a 1977 Hondamatic 750A , the fella I am getting them from dont like small talk 
So can I use my Hondamatic carby bracket with the idle up solenoid and the throttle cables with out too many head whatsanames...

I believe these(K7 carbs) also have the fuel squirter like my stock Hondamatic jobs...



Hondaman recommends the idle up for the slusher if ya change carbys on the auto

Some use round tops and put up with the flat spot, bugger that if I can help it

vik...

G'day Vik, to be honest, I've no idea. I've never owned an auto, much less worked on one, so I'd defer to Hondaman's advice, re: idle solenoids. They both run a form of PD carb but much smaller venturi (22mm?) and tiny inlet ports and inlet valves on the auto, so 28mm K7 carbs and a head with bigger ports and valves with a bigger cam will transform your taxi into a terror.

[vik351]

Well to my untrained eye, looks like the bracket size was the same used and they reduced the venturi ,throat only to keep it simple...



doesnt look impossible 

I could always send ya the bracket 

vik...

carbs off

[Terry in Australia]

Yeah.............. The bracket looks completely different from a K7/8 - F2/3 carb bracket, but yeah, send it over mate, and I'll see if there's an easy fix.

[754]

I am running a 78 F motor in a 74 frame, with 74 carbs and rubbers.  Oil em and push them on.

[vik351]

Yeah.............. The bracket looks completely different from a K7/8 - F2/3 carb bracket, but yeah, send it over mate, and I'll see if there's an easy fix.

Bugga...  Didn't think it would be that straight forward... not much point in sendin that over then, cos your carbs and head are a match the problem is my end fittin the idle up doo dad in there...

Prolly be there after Chrissie when the caravan parks free up a bit...  Will bring my bitsa crap with me and if your in the mood we can have a bit of a chinwag ...

vik...

[Terry in Australia]

Yeah.............. The bracket looks completely different from a K7/8 - F2/3 carb bracket, but yeah, send it over mate, and I'll see if there's an easy fix.

Bugga...  Didn't think it would be that straight forward... not much point in sendin that over then, cos your carbs and head are a match the problem is my end fittin the idle up doo dad in there...

Prolly be there after Chrissie when the caravan parks free up a bit...  Will bring my bitsa crap with me and if your in the mood we can have a bit of a chinwag ...

vik...

Sounds good Vik, and I meant to ask, with the Vik351 tag, you're a Ford V8 guy, yeah? I've also got a soft spot (between my ears) for Cleveland V8's.

[vik351]

Yeah.............. The bracket looks completely different from a K7/8 - F2/3 carb bracket, but yeah, send it over mate, and I'll see if there's an easy fix.

Bugga...  Didn't think it would be that straight forward... not much point in sendin that over then, cos your carbs and head are a match the problem is my end fittin the idle up doo dad in there...

Prolly be there after Chrissie when the caravan parks free up a bit...  Will bring my bitsa crap with me and if your in the mood we can have a bit of a chinwag ...

vik...

Sounds good Vik, and I meant to ask, with the Vik351 tag, you're a Ford V8 guy, yeah? I've also got a soft spot (between my ears) for Cleveland V8's.

Ah yea, had a few XY,s all with Clevos, now thats a money pit...

Brought the sons up on 1970 Capris

Bloody hell... wish we kept them all now 

Even bought a POS BA turbo when they came out 

Gimmie old school any day...



vik...

[desertrefugee]

Common engines, but some funny looking Fords for us stateside readers.  Almost expect a young Mel Gibson to be standing nearby. 

[jukku]

So Terry,you could perhaps advise me on fitting K7 carbs and head to a 1977 Hondamatic 750A , the fella I am getting them from dont like small talk 
So can I use my Hondamatic carby bracket with the idle up solenoid and the throttle cables with out too many head whatsanames...

I believe these(K7 carbs) also have the fuel squirter like my stock Hondamatic jobs...


Hondaman recommends the idle up for the slusher if ya change carbys on the auto

Some use round tops and put up with the flat spot, bugger that if I can help it

vik...
[/quote]

The solenoid valve and throttle opener sets from the Matic carbs are bolt on to the K7 carbs. Throttle return springs are identical.

[vik351]

So Terry,you could perhaps advise me on fitting K7 carbs and head to a 1977 Hondamatic 750A , the fella I am getting them from dont like small talk 
So can I use my Hondamatic carby bracket with the idle up solenoid and the throttle cables with out too many head whatsanames...

I believe these(K7 carbs) also have the fuel squirter like my stock Hondamatic jobs...


Hondaman recommends the idle up for the slusher if ya change carbys on the auto

Some use round tops and put up with the flat spot, bugger that if I can help it

vik...

The solenoid valve and throttle opener sets from the Matic carbs are bolt on to the K7 carbs. Throttle return springs are identical.
[/quote]

Wow, just made my day...

Thanks for that jukku...!!!

vik...

[Terry in Australia]

The solenoid valve and throttle opener sets from the Matic carbs are bolt on to the K7 carbs. Throttle return springs are identical.

Good to know mate, thanks for that. I've never had any interest in the auto's, so no first hand knowledge.

[vik351]

Common engines, but some funny looking Fords for us stateside readers.  Almost expect a young Mel Gibson to be standing nearby.

 

https://www.carsales.com.au/editorial/details/ford-falcon-gtho-phase-iii-sets-auction-record-113183/

Aint hind sight a #$%*...!!!

vik...

[Don R]

 Thanks for the info.  I have an A parts bike and a set of K7 carbs ready to go on if it gets built. I had wondered about using the solenoid to bump up the rpm while staging at the drag strip. Probably not legal in tracks with no electronics class rules but might work.