jet needle z1000

[snowyz9]

Replacing the needles ,My plan is to put z1000a1 needles in my a2 as a2 is leaned out stock . photo shows , new A1 stock on left , Question as seems to be a great difference see needle on left ,lot shorter with them bits on as well , and there is a spring in the throttle valve .
Can i just leave of all the gumf , or do i need to change the throttle valves and needle jets ??

[snowyz9]

Ps , if you bought a carb repair kit , they seem to be all the same 77-81 , just worried about the throttle valve and the difference with spring in etc , alternately , ive jetted up main and pilot jet , shall i just leave be the stock a2a needles and valves ? my reason for changing , was the a1 needles are not so lean

[ZedHead]

A1 used 5CN8 & A2 used 5DL31. Both should be 57.4 mm according to my Mikuni data

[snowyz9]

Hi ZEDHEAD , Thanks for answering , Mine is an A2A needle measures 52mm , was the above setup , where the needle goes through a spring in a recessed hole in the throttle valve from the top , better or worse

[8 Valve Mark]

A1 used 5CN8 & A2 used 5DL31. Both should be 57.4 mm according to my Mikuni data

any reference to 5CN7-4 dave? the a2a factory manual lists this part number (usa lean carburetion system for emission control) m.

[ZedHead]

A1 used 5CN8 & A2 used 5DL31. Both should be 57.4 mm according to my Mikuni data

any reference to 5CN7-4 dave? the a2a factory manual lists this part number (usa lean carburetion system for emission control) m.

Yes, it is only 51mm long. Which suggests they were completely different carbs. I am not familiar with the variations. Pumpers maybe?

[snowyz9]

except jets carbs seem the same

[snowyz9]

a photo of

[8 Valve Mark]

your right ian, they're the same apart from the needles n jetting. it seems like you might have to track the usa part down..
dave, the 28mm pumpers have 5CN17-3 listed..

[ZedHead]

Getting closer then, I think the only challenge will be finding a matching emulsion tube.

[snowyz9]

On further looking , dont the lifters look different , top left photo

[ZedHead]

Yes, Do you need to change the needle?

[snowyz9]

Not really , just had the idea of putting a1 needles in , the throttle valves are 2.0 , A1 and maybe A2 are 1.5 , are these carbs power sucking with them needles ? if so , would i be better off buying different carbs

[ZedHead]

Not really , just had the idea of putting a1 needles in , the throttle valves are 2.0 , A1 and maybe A2 are 1.5 , are these carbs power sucking with them needles ? if so , would i be better off buying different carbs

Haha definitely buy new carbs. I know a man that can

[ZedHead]

There is little difference in taper between 5CN7 and 5CN8, just the length.

Without teaching granny to suck eggs, Power loss could have many causes. It would be useful to know more about your bike. How much is stock. bore, valves, exhaust, air filter etc ....

Have you taken some spark plug readings at different rev ranges?