Jetting difference: KZ750E/H & Spectre Keihin's?

Just finished rebuilding a set of Spectre CV34 Keihin's. They started out as black and it was a LOT of work to clean all that black paint off and make them bright and shiny again. At any rate, I've done a few sets of the regular CV34 Keihin's before, from 750E/H bikes, and these carbs are almost the same except for minor changes, most noteworthy are in the jetting. The early bikes use 62/125 Primary/Secondary Main Jets, whereas the Spectre carbs use 65/90's. The needle is drastically different between the two carbs as well; the early needle is sharp and pointy whereas the Spectre needle is blunt ended without as much taper. Is the difference in the needle the reason one bike ran a 125 secondary main and the other a 90? The engine mechanicals are almost identical between the different 750's other than the Spectre shaft drive of course.

Can these carbs be installed on a 750E/H and run down the road without issue, or will the jetting cause problems? I've got some spare E/H jets that could be installed I suppose if necessary. My plan is to off these things to someone in need and want to provide something that's point and shoot if possible.

Thoughts?

Thoughts

I cant see any reason why the Spectre carbs with Spectre jets would not work just fine on tbe E or H models given the main model difference is shaft vs chain drive.

But, could one swap in E/H size jets and E/H needle ? The Haynes manual lists the Spectre Primary main air jet as 100 vs the E/H Primary main air jet as 130. I'm not sure exactly where these are located but should be in the openings in the intake side of the carbs and not possible to change.

For this reason I'm thinking the first option possible but the second maybe not.

You could offer them with a money back garantee ?

Ah, good point about the air jets. I'll get all the appropriate info from the Spectre manual to compare. Guess I could always throw these new carbs on my bike to see how they run. Was hoping to avoid that though.

Guess I could always throw these new carbs on my bike to see how they run. Was hoping to avoid that thoug

h.

Might be the only option and who knows but you might find you prefer the Spectre carbs.

KZ 750s are pretty rare in my neck of the woods. In the 12 or 23 years i have had the bike I have seen only two 750LTDs and only a single E2 or E3 model. I have never seen an early 80s 750 Spectre. The KZ 750/4s must not have been popular in Canada

I've redone four sets of these carbs now and didn't have much problem finding a taker. I may try to sell these things the way they are and bail out and test them on my bike if I get stuck. My bike runs so dang well i'm really hesitant to take the carbs off.

P1030288 by nessism , on Flickr

P1030290 by nessism , on Flickr

As Nessim said: jet needles are totally different.
But don't forget about the needle jet. Size is different also.