TOPIC:

Hi all,

If I don't have any power below 55 00rpm would that mean my carbs weren't rejetted for the velocity stacks and 4-into 1?
I'd be happy with that because I'd like to get it back to stock. ( except for the rare as rocking horse ?*&^#, i've been told)
She start and runs well except for the lack of power. No smoke carbs cleaned etc.

If the pilot jets are still stock I'd expect it to be well lean at low revs. Try cleaning the plugs then take it for a ride only using the low rev range then check your plug colour. Chances are they will be whiter than Doc Emetts hair.

OK will do .Thanks. Might have a ride tomorrow.

And please install real air filters. Those velocity stacks will just ruin the intake valve seats and rings.

baldy110 wrote: And please install real air filters. Those velocity stacks will just ruin the intake valve seats and rings.

Please explain how "Those velocity stacks will just ruin the intake valve seats and rings."
I missed that when replacing the rubber stock intake boots on my bike with Mikuni metal ones.

Velocity stacks are not air filters. Allowing unfiltered air into the engine beats up the intake valves, seats and accelerates ring wear.

No eBay APP ID and/or Cert ID defined in Kunena configuration

baldy110 wrote: Velocity stacks are not air filters. Allowing unfiltered air into the engine beats up the intake valves, seats and accelerates ring wear.

Ram Air and PX velocity stack filters provide some engine protection.

I usually find a trail of fine particles trapped in the fuel blow-back coating on the inside of the stacks. It may be fine dust that gets sucked through the filter, or tiny fragments of filter material itself. It may just be mist-residue from the crankcase, drawn through the air box and mixed in with the stream of filtered air.

baldy110 wrote: And please install real air filters. Those velocity stacks will just ruin the intake valve seats and rings.

Yes that's the plan. Refit a stock airbox ( if I can source one ( or install a remanufactured Z1 airbox),
I'm hoping it'll run better with the stock exhausts and aitbox refitted.

So at the moment there's not too much power , but it runs very smoothly , strangely enough.

Those are Z1 or early Z1A carbs on what looks to be a KZ900 engine. Your pipes are badly blued, suggesting your pilot fuel/air mixture is very lean. What pilot jets are you using and what position are your needles? Also, how far are your fuel air screws backed off?

I'm planning to take a look this weekend.
Thanks for the comments guys. I guess I'm in luck and that all I need is to get an airbox and the 4 exhaust pipes back and she'll run fine. :

You will have a difficult time finding an original airbox for a '76 900. You could do what I did with my '80 KZ1000. I installed a Z1 style airbox.

Th. I've enlarged the mains from 120 to 150 and it still won't pull strongly. But it runs better than before. and idles great.
It start first try, electrically or with the kickstart
Would going to 180 or so be normal for just velocity stacks?
(Love the ease with which I can change the mainjets)
@ hardrockminer:I'm giving it a few more tries before buying a Z1 aitbox, it's cheaper getting the jetting right as it is now.
I've decided to sell this one and concentrate om my '75 build so I'm trying to get it running well the least cost.
But it's nice to know it works.
Are you using the stock jetting?