Topic: Quality K8 carb boots for early k head to Mikuni 34mm Flatslides

[dragracer]

Can't a #1 boot be flipped over and fit on #4, and likewise for #2 and #3?

  I wondered that also but Honda gave them each a different part number.

Yes, because each one is marked on the top with the cylinder #. I recall seeing some boots that had a 1 on one side, and a 4 on the other side: if used on the #1 cylinder, the 1 went on top with the 4 on the bottom, and if used on the #4 cylinder the 4 went on top. Try it and see if it works or not.

My plan is to try your suggestion Scottly.  I much rather use the OEM Honda parts. 

[Medyo Bastos]

Can't a #1 boot be flipped over and fit on #4, and likewise for #2 and #3?

  I wondered that also but Honda gave them each a different part number.

Yes, because each one is marked on the top with the cylinder #. I recall seeing some boots that had a 1 on one side, and a 4 on the other side: if used on the #1 cylinder, the 1 went on top with the 4 on the bottom, and if used on the #4 cylinder the 4 went on top. Try it and see if it works or not.

Yes


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[willbird]

Can't a #1 boot be flipped over and fit on #4, and likewise for #2 and #3?

  I wondered that also but Honda gave them each a different part number.

Yes, because each one is marked on the top with the cylinder #. I recall seeing some boots that had a 1 on one side, and a 4 on the other side: if used on the #1 cylinder, the 1 went on top with the 4 on the bottom, and if used on the #4 cylinder the 4 went on top. Try it and see if it works or not.

That is how the new OEM boots I bought from Ebay are, I never knew there were FOUR part numbers for boots 1-4 ?? Always presumed that there were only two. I have been messing around cad modeling intake boots and just ordered a digital height gage to actually measure/model the features on the cylinder head and work from there rather than using a boot and working from those numbers.

Bill

[scottly]

The original K7 boots I have are actually marked 1, Z, 3, 4.

[dragracer]

The original K7 boots I have are actually marked 1, Z, 3, 4.

I went ahead and ordered another #1 OEM boot. I'll try it on the #4 side. It doesn't have to be exact stock  spacing anyway because the 34's are off a bit anyhow. 

[Don R]

Can't a #1 boot be flipped over and fit on #4, and likewise for #2 and #3?

  I wondered that also but Honda gave them each a different part number.

Yes, because each one is marked on the top with the cylinder #. I recall seeing some boots that had a 1 on one side, and a 4 on the other side: if used on the #1 cylinder, the 1 went on top with the 4 on the bottom, and if used on the #4 cylinder the 4 went on top. Try it and see if it works or not.

That is how the new OEM boots I bought from Ebay are, I never knew there were FOUR part numbers for boots 1-4 ?? Always presumed that there were only two. I have been messing around cad modeling intake boots and just ordered a digital height gage to actually measure/model the features on the cylinder head and work from there rather than using a boot and working from those numbers.

Bill.

 The thing to remember is these are K8 boots for the keyhole carbs, not the same as the other cb750 boots.

[dragracer]

Can't a #1 boot be flipped over and fit on #4, and likewise for #2 and #3?

  I wondered that also but Honda gave them each a different part number.

Yes, because each one is marked on the top with the cylinder #. I recall seeing some boots that had a 1 on one side, and a 4 on the other side: if used on the #1 cylinder, the 1 went on top with the 4 on the bottom, and if used on the #4 cylinder the 4 went on top. Try it and see if it works or not.

That is how the new OEM boots I bought from Ebay are, I never knew there were FOUR part numbers for boots 1-4 ?? Always presumed that there were only two. I have been messing around cad modeling intake boots and just ordered a digital height gage to actually measure/model the features on the cylinder head and work from there rather than using a boot and working from those numbers.

Bill.

 The thing to remember is these are K8 boots for the keyhole carbs, not the same as the other cb750 boots.

Correct Don. The head side is comparable to all other K heads but the inlet side is larger. They work perfectly for the 34mm Flatslide Mikunis when installing them on any head except the F2/3 which has larger intake spigots. I typically use a drum sander roll on my drill to open up the inlet a tad larger so the 34's won't be as hard to slip on. I cut a little at a time to be certain its snug. In theory,  1 and 4 should be similar in configuration as you're only rotating the boot, 180 degrees on the spigot. 

[Don R]

 It makes perfect sense to me. It got me curious about the K0/K1-6 carb rubber difference. I've had mid-year carb rubbers on an early bike since before I joined here.

[madmtnmotors]

That is how the new OEM boots I bought from Ebay are, I never knew there were FOUR part numbers for boots 1-4 ?? Always presumed that there were only two. I have been messing around cad modeling intake boots and just ordered a digital height gage to actually measure/model the features on the cylinder head and work from there rather than using a boot and working from those numbers.

Bill

Oooooo... 3D CNC machined aluminum intake manifolds with wide flat rubber o-rings on the inlet port at the head and an o-ring on the carb outlet. Make it so!

[willbird]

That is how the new OEM boots I bought from Ebay are, I never knew there were FOUR part numbers for boots 1-4 ?? Always presumed that there were only two. I have been messing around cad modeling intake boots and just ordered a digital height gage to actually measure/model the features on the cylinder head and work from there rather than using a boot and working from those numbers.

Bill

Oooooo... 3D CNC machined aluminum intake manifolds with wide flat rubber o-rings on the inlet port at the head and an o-ring on the carb outlet. Make it so!

I am fresh out of CNC's but the general idea is to create a fairly accurate 3D model and then we can examine all kinds of ideas :-).

Bill