Topic: Carb PD41A - PD42B throttle valves

[dakota]

Hi,
I have 2 carbs for a 750F2, PD41A en PD42B.
They have different throttle slides. The 41A has slides that are 3 times heavier than the ones of the 42B.
The ones from the 41A are chrome lined , the others are not.
Which valves should I use? Is there a difference in performance?
greetings

[bollingball]

dakoda I don't have any 41 carbs. I do have 42a & 42b banks and sure enough the 42a bank are chrome or silver in color and the 42b is not. I never noticed that before.
They do have different size jets. You should not change the slides from one body to the other IMO Nothing else to tell you maybe someone else will chime in.
                                           Ken
 

[dakota]

My mistake, PD42A and PD42B

[bollingball]

The 42a came off a 77 750 F model the The 42b is on my stock 78 750 K model
Now what is your question?
If you find out why they have different colored slides let me know. I'm curious now

                                              Ken

[dakota]

The throttle slides have a different weight.
The chrome ones are 3 times heavier than the other ones.
Is this weight going to have some influence on the performance?
Are the chrome slides better or ...
 

[voxonda]

Hello Dakota,

The lighter ones are from the K7. I found out exactly the same thing, a few months ago. Have put the lighter ones in my replica, purely due to the weight advatage, and the carbs performs still good with them. Have made some other changes to these carbs, but it looks like they give no disadvantage. Since size is the same they should work the same. The weight difference may be the reason for the lighter return spring on the K7 carbs.

Cheers, Rob

[dakota]

That's the answer I was looking for!
Thanx Rob