Topic: CB750A pilot jets

[Fimlimbimjim]

Hi all
Probably a silly question but here goes.
I have just purchased a 1977 CB750A. Now it shows the classic signs of some blocked pilot jets. However the exploded diagram I have from the workshop manual Show no pilot jets where I would expect them. That is where they are on other models and there are none in the carbs. I foolishly decided they were blank and undrilled so cleaned out everything else and put things back together. So no improvement.

Now I guess there are holes wot should be cleaned. If anyone has any cleaning tips or can let me know holes or not I would be very grateful.

Ta Jim

[newday777]

As you have? Stock PD44A carbs?? Then they probably have pressed in slow jets that need to be pulled out to clean properly.
I don't know the Automatic carbs to verify.
BTW welcome to the forum.
Go to the new members section and introduce yourself and your bike. Pictures are always welcome. Where are you located?

[Fimlimbimjim]

Hi thanks for the reply.
From pictures of other carbs there are brass push in jets in front of th main jet. In my carbs and the CB750a pictures there is only the casting where I would expect the jet to be?

Confused Jim

[newday777]

Hi thanks for the reply.
From pictures of other carbs there are brass push in jets in front of th main jet. In my carbs and the CB750a pictures there is only the casting where I would expect the jet to be?

Confused Jim

Post pictures of your carbs

[Fimlimbimjim]

Will do.
 Just fishing for an answer before I take them apart again. Trouble is I have 9 other bikes and they all seem to work themselves apart. Then I lose the bits 

[Fimlimbimjim]

Well of course the pressed in pilot jets are there (#38). Why I didn't see them for what they are Will have to be put down to old age.

Two were blocked one badly enough to need a tickle from a flame to loosen up the goop.
So back together, runs better now, nearly ticks over. No1 cylinder is a little lazy so another carb investigation there next weekend. Also the check valve in the bottom of the accelerator pump appears to be blocked I guess ultrasonic cleaning is in order?

Rock on

Jim

[newday777]

Hi thanks for the reply.
From pictures of other carbs there are brass push in jets in front of th main jet. In my carbs and the CB750a pictures there is only the casting where I would expect the jet to be?

Confused Jim

That's why you need to post pictures of your carbs....


There's a flat section on the head side of the intake throat that should have the PD numbers stamped in.

[Fimlimbimjim]

Thanks for the replies.
Yes standard PD44 carbs
Now the jets are clean it's running on all four. Needs a balance but not bad for now. So onto the accelerator pump and fast tickover valve thingy.
I'll keep my eyes open for this bit 

Jim