TOPIC:

Hi WiredGeorge (or anyone with a good point), just started into a 74 Z900 which I bought not running. Stripped the carbs to find plenty of scum from evaporated fuel in the bowls and emulsifier etc...

Anyway: putting it all back together and being time resticted I thought it prudent to quickly get WG's thoughts on a few points.

I believe I have a stock set of VM26's here but I cannot find a number anywhere to confirm that. They have airscrews and the syncronizing screws are on the outside of the carb.

I think the engine has been modified but until I open it I cannot confirm that either. The carbs have definately been messed with previously - the needles have been raised to the max and the main jet is a 130 of plastic construction (?)

My questions:

Float level setting on bench = 1 inch or 25mm from carb housing to summit of float. Is that what you recommend WG?

Airscrews or (idle mix screws to me) = I have set to 1.5 turns out from bottom to start with. Good idea?
Is it esssential to have the o-ring on the screw? They are long gone...

Syncronizing: I have 'balanced' them all at 0.028 thou/.7 mm from piston to body as accurately as possible. Again; is this what you would recommend WG?

Lastly; any tricks or mods I can do while they are apart for now?

Thanks for your advice and time on this forum.

Regards

Post edited by: WTF!, at: 2006/09/06 21:30

You likely have VM28SC Z1 carbs with the outside sync mechanisms. I suspect your carbs have the largish 17mm drain plugs on the bowls? If they do, 24mm between top of float and gasket mating surface. Your jet needles SHOULD have a badge # 5J9... reclip to 3rd slot. The pilot jets are likely #20 as there are no alternatives because the style of pilot is unique to the 73/74 Z1/Z1A carb. Use #112.5 mains with a stock airbox. You can go to #120s with pods or pods w/aftermarket pipes. Sync the carbs with gauges and don't rely on just a bench sync. If your #4 carb sync adjuster is "fixed", you can remove the hex cap and use vise grips to turn the nub as it will adjust the slide height for that carb. They went from fixed to adjustable at some point in 74 so yours MAY have an adjuster on the fourth carb. Use orings on the air screws or they will leak air into the pilot system and idle will be hard to set and keep steady.

Awesome WG, many thanks for your reply. I neglected to mention the pods and aftermarket pipes, so I will take your thoughts regarding that. Considering that, should I still reclip to the 3rd position on the needle?
The #4 carb does have the adjustable sychroniser and I do have the large 17mm drain plugs.
Thanks
Steve NZ

WG, I have returned the needles to the 3rd clip since I did the same with my other Z to tune out some flat spots and it cleared the problem.

I have just found that the main jet emulsion tubes are different. There are two that pass a 7/32 drill bit without restriction and two that pass the bit to the point of join between the treads for the jet and the emulsion section. Is this normal and since I didn't pay attention while dismantling; should these two restricted jets be on the outer carbs and the two unrestricted on the inner (2-3) for cooling?
Cheers

All four emulsion tubes should be the same. They will be shoulderless without a means for retaining an oring. The hole diameter in the tube should be the same.

I guess someone has goofed with them too.
I might run a 7/32 through them with a quick polish to equal them all out.
Thanks WG.

damn, dude; just cos it fits doesn't mean its correct...