Topic: 1976 Honda cb750K Carb Question

[BenelliSEI]

Had a great “ski break”, back on my K6 project today. Dismantled the carb rack I plan on using (086A). I have #105 mains and #40 idle jets in these carbs, that are apparently what I need. The needle is marked “271301”.

Anyone know if that is stock brass or an aftermarket part?

It has 5 clip positions and is clipped in #3 middle. The attached chart suggests they should be in the 4th slot from the top (Mark P. calls it the “blunt end”). I’ll start with it there.

Any other suggestions?

[CycleRanger]

I believe that "271301" is original Keihin.

Here's some comments about about 086A carbs.

http://forums.sohc4.net/index.php?topic=175304.0

[BenelliSEI]

I believe that "271301" is original Keihin.

Here's some comments about about 086A carbs.

http://forums.sohc4.net/index.php?topic=175304.0

Thanks for that link! Excellent read and looks like I’ve collected up just what I need.
Much appreciated!

[M 750K6]

My experience was the opposite to the thread link above: I found the Keyster needles were thinner than the old ones I'd replaced. I was fouling plugs until I took the Keyster brass out. They came in a carb refurb kit from David Silver in March last year.

[BenelliSEI]

My experience was the opposite to the thread link above: I found the Keyster needles were thinner than the old ones I'd replaced. I was fouling plugs until I took the Keyster brass out. They came in a carb refurb kit from David Silver in March last year.

I’m definitely sticking with the original.

[MauiK3]

Why can't anyone get the brass right? What a shame.

[BenelliSEI]

Why can't anyone get the brass right? What a shame.

I think there are good kits out there. When I did my last 2 X K0s, I used full kits from Yamiya, for the correct carbs. No idea what brand they were, generic packaging stamped “Made in Japan”. Those bikes ran then, and still run now, flawlessly.

[Scootch]

I used Yamiya kit as well. It and their recommendations work. I don't understand why people insist on going through the gyrations and drama...

[BenelliSEI]

I used Yamiya kit as well. It and their recommendations work. I don't understand why people insist on going through the gyrations and drama...

Agreed.

[M 750K6]

I used Yamiya kit as well. It and their recommendations work. I don't understand why people insist on going through the gyrations and drama...

I had no intention of playing a dramatic part. I just bought a carb refresh kit from a reputable source here in the UK. Bike didn't run properly until I swapped the brass parts back out. 9 months of irritation I didn't ask for, let alone 'insist' on  .

[willbird]

I used Yamiya kit as well. It and their recommendations work. I don't understand why people insist on going through the gyrations and drama...

I had no intention of playing a dramatic part. I just bought a carb refresh kit from a reputable source here in the UK. Bike didn't run properly until I swapped the brass parts back out. 9 months of irritation I didn't ask for, let alone 'insist' on  .

I just looked and the Yamiya kits look nice but they are $75ish USD each so that might be a barrier there maybe. But to balance that four supposedly OEM float valves are $100-$150. I bit the bullet and paid $89 shipped for the ones I bought last year for my K2.

Bill

[Scootch]

Just to be clear that's $75 for 4 carbs. And look at what you get. You even get the gaskets for the top of the carbs. Which by the way, you should have those gaskets installed.

[willbird]

Just to be clear that's $75 for 4 carbs. And look at what you get. You even get the gaskets for the top of the carbs. Which by the way, you should have those gaskets installed.

Oh I am overjoyed to see that :-). My misunderstanding then. $75 total is a great deal. My top gaskets were magnificent when I ultrasonic cleaned my K2 carbs

Bill

[willbird]

Just to be clear that's $75 for 4 carbs. And look at what you get. You even get the gaskets for the top of the carbs. Which by the way, you should have those gaskets installed.

Oh I am overjoyed to see that :-). My misunderstanding then. $75 total is a great deal. My top gaskets were magnificent when I ultrasonic cleaned my K2 carbs. I often think however that to keep on using something that is still good is the epitome of recycling :-). And the original brass parts often are still in great shape. Still a source of really nice ones to swap out for poorly made brass that a PO swapped in is a great thing :-).

Bill

[BenelliSEI]

Bill I agree on your recycling comment. I’m pretty much reusing everything on these carbs. I do like to change float bowl gaskets and since I bought a package of +100 of the “0” rings for the fuel tees, I always do them. They’re one of the few things that require dismantling the entire rack and so annoying when they leak!

[willbird]

Bill I agree on your recycling comment. I’m pretty much reusing everything on these carbs. I do like to change float bowl gaskets and since I bought a package of +100 of the “0” rings for the fuel tees, I always do them. They’re one of the few things that require dismantling the entire rack and so annoying when they leak!

Oh for sure the ones on the fuel Tees :-). Those O rings come in one of the harbor fright O ring kits I have read here :-).

Bill

[BenelliSEI]

This set of 086A carbs is almost done. Going on my cb750K6 project. They are fitted with all original brass as per the chart at the top of these posts. They all came with black, plastic floats. Set them at the same height as the original brass floats?

[HondaMan]

This set of 086A carbs is almost done. Going on my cb750K6 project. They are fitted with all original brass as per the chart at the top of these posts. They all came with black, plastic floats. Set them at the same height as the original brass floats?

Those black plastic ones usually set up at 26mm from the bare gasket surface. I still stagger them 25/26mm so they don't tend to weep fuel so much when parked on the sidestand in summertime.

[BenelliSEI]

This set of 086A carbs is almost done. Going on my cb750K6 project. They are fitted with all original brass as per the chart at the top of these posts. They all came with black, plastic floats. Set them at the same height as the original brass floats?

Those black plastic ones usually set up at 26mm from the bare gasket surface. I still stagger them 25/26mm so they don't tend to weep fuel so much when parked on the sidestand in summertime.

Thanks!

[M 750K6]

This set of 086A carbs is almost done. Going on my cb750K6 project. They are fitted with all original brass as per the chart at the top of these posts. They all came with black, plastic floats. Set them at the same height as the original brass floats?

Those black plastic ones usually set up at 26mm from the bare gasket surface. I still stagger them 25/26mm so they don't tend to weep fuel so much when parked on the sidestand in summertime.

I like this idea, and will try it next time carbs are off, for peace of mind that I'm not washing my bore with fuel on the sidestand. But, isn't 25mm a higher fuel level, as the float is 1mm nearer the top of the carb before it shuts off?

[BenelliSEI]

Mmmm. That makes sense. I’ll stick with “snug 26” on both.