Author Topic: 78 750K new on the block (Read 2082 times)

xcbxer · « **on:** February 09, 2006, 02:25:26 PM »

First post;

Just finished restoring my $50 underground garage find - a 78 750K. Test ride yesterday (15 degrees F) was smooth, and the 4 into 2 aftermarket exhaust note is sweet. It took a month and only $300 in parts, but I should also count in the $300 blown for the F150 tailgate damage during the pick up.

Between the carbs there are 3 interconnecting fuel supply pipes and 3 accel pump distribution tubes as shown in the shop manual and Clymers.

I have a 3rd set of 3 connector tubes further forward near the base of the throttle valve. This 3rd set is connected to a 1/8 tube coming from the left side of #2 carb (much like the fuel supply). It's not in the manuals and I can't find or remember where this 1/8 tube connects to. Is it a fuel bowl vent?

eldar · « **Reply #1 on:** February 09, 2006, 04:32:44 PM »

You can download the k8 manual on this site. It is large, so if you have dial-up, go to a friends house with a high speed connection and download it. The clymers barely show any pics of our bikes and so work is hard to do with one of those.

dusterdude · « **Reply #2 on:** February 09, 2006, 04:42:24 PM »

aww gee,not another one

eldar · « **Reply #3 on:** February 09, 2006, 05:28:52 PM »

Dont mind him. He is just threatened by us K8 riders!

Bob Wessner · « **Reply #4 on:** February 09, 2006, 05:32:24 PM »

Quote

You can download the k8 manual on this site. It is large, so if you have dial-up, go to a friends house

If you have clean dial-up and running at least 50kb you can do it. Might consider starting it before you go to bed though.

xcbxer · « **Reply #5 on:** February 09, 2006, 07:04:48 PM »

Thanx for the inputs, but I already had the site K8 shop manual up and loaded, and there was no sign of that 3rd set of inter carb tubes.

Looking closer a second time, I see the throttle shaft return spring is supposed to be the pull kind where mine is the rotational type.

Otherwise all other carb details look the same.

Engine number 750E 3016014 is in the K8 range - unless someone has a quickie insight, I'll go see what the dealer microfisches turn up.

Lumbee · « **Reply #6 on:** February 10, 2006, 07:31:36 AM »

..well X, u'v stumped me...which isn't saying much

I do sort of consider myself a 77/78 750 carb expert...I'm in the processes of reassembling my 3rd set. I don't recall any 3rd set of tubes. Are they rubber or aluminum? Are you sure u'r not confusing the choke or throttle arm/bar for a tube? Thats the only thing I can think of. If u have a dig. cam. snap a pic and post it...I'd luv to see it to get to the bottom of it...

eldar · « **Reply #7 on:** February 10, 2006, 07:54:28 AM »

Well you have a set of aluminum tubes with orings. Then you have a smaller set or rubber tubes. I cant think of a third set either right now. Maybe when I get home I might remember to look. Are you sure though that you have 78 carbs? My throttle return is circular as is my butterfly choke valve return spring. There is another straight spring to but it is for something else I think.

xcbxer · « **Reply #8 on:** February 10, 2006, 01:12:27 PM »

Maybe this is a vacuum supply for a later K8 variant with auto petcock. Too cold out there to start her up. Also posted pics in the gallery.

Looking for Carb Colombo.

Gordon · « **Reply #9 on:** February 10, 2006, 01:20:48 PM »

Pretty sure that's just the float bowl vent there.

Lumbee · « **Reply #10 on:** February 10, 2006, 01:41:36 PM »

...are you talking about this tube? (see red arrow in pic)

...if so I've never gotten a def. answer on what this tube is. I've never done anything with mine. I wonder if its some sort of vent tube...

Lumbee · « **Reply #11 on:** February 10, 2006, 01:45:43 PM »

...upon closer observation are you talking about the tube in the in the pic with the green arrow? I'm really stumped now ...that looks familiar...I'll have to check out my carbs this weekend and see any any of the carbs I have, have this tube. Either way I won't be able to tell u its purpose.

For sure there were many variations of the 77/78 carbs...

jtb · « **Reply #12 on:** February 10, 2006, 03:14:04 PM »

It may be time to spin the K8 guys off to their own forum. Hell, it may be past time.

Gordon · « **Reply #13 on:** February 10, 2006, 03:26:27 PM »

Somebody else chime in here, but I'm almost positive that's the float bowl vent. The tube with the red arrow leads into a "T" fitting that goes into the tube with the green arrow that connects to all four carbs venting the float chambers to the atmosphere in order to equalize the pressure.

xcbxer · « **Reply #14 on:** February 10, 2006, 03:57:42 PM »

The red arrow seems to be pointing at the fuel line. The green arrow has got it - the mysterious 3rd tube set. The hose you see in the foreground is connected to the mysterious tube set at the left side of #2 carb. This is a 1/8 hose and it has a spring clip on the free end - so it must have been connected to something at one time or another.

dusterdude · « **Reply #15 on:** February 10, 2006, 04:28:14 PM »

Quote from: jtb on February 10, 2006, 03:14:04 PM

It may be time to spin the K8 guys off to their own forum. Hell, it may be past time.

i agree

mick750F · « **Reply #16 on:** February 10, 2006, 05:05:24 PM »

If it's what I think you're talking about it's a vent. It runs over the top of the airbox where there is a clamp for it. It then connects to another section of hose. Right now I can't remember if it runs to the separator or is free breathing. I'll check mine tomorrow.

Mike

mick750F · « **Reply #17 on:** February 11, 2006, 11:11:06 AM »

Just checked mine...It hangs free down the back of the filter box.

Mike

xcbxer · « **Reply #18 on:** February 11, 2006, 05:24:23 PM »

As usual the carbs never go back on just once.

Had them off again today, looked inside and the tubes under scrutiny are indeed fuel bowl vents. Also found a clip on top of the air box to secure the hose coming from #2 carb. After that there is a spring clip on the end but I can't see where it connects to.

The manuals don't show them and I would have thought the overflows function well enough as vents, but as a useless emission gesture it should go into the airbox.

mick750F · « **Reply #19 on:** February 11, 2006, 09:07:42 PM »

Quote from: xcbxer on February 11, 2006, 05:24:23 PM

As usual the carbs never go back on just once.

Had them off again today, looked inside and the tubes under scrutiny are indeed fuel bowl vents. Also found a clip on top of the air box to secure the hose coming from #2 carb. After that there is a spring clip on the end but I can't see where it connects to.

The manuals don't show them and I would have thought the overflows function well enough as vents, but as a useless emission gesture it should go into the airbox.

Well I'm not sure if you're mis-reading my post or I'm mis-reading yours but the tube does NOT go into the airbox. After the clip on top it simply hangs down the outside of the box on the backside. As far as the overflows acting as vents...they might as long as they're not acting as overflows. Once they have gas running through them they are no longer vents.

Mike

xcbxer · « **Reply #20 on:** February 12, 2006, 06:01:07 AM »

I was just speculating the airbox because on the open end of the hose I have a rusty springclip, so it sure looks like it was attached to something at one time.

You are right about the overflows, they will trap fuel.

Regardless, thanx to all, the question of function has been answered (except for why it doesn't show up in any K8 manual).

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Author Topic: 78 750K new on the block (Read 2082 times)

xcbxer

eldar

eldar

xcbxer

eldar

xcbxer

xcbxer

xcbxer

xcbxer